View source for Bulk carrier

{{Short description|Ship made to transport unpackaged bulk cargo}}
{{Use dmy dates|date=February 2021}}
{{Morecite|date=July 2023}}

{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=[[File:Sabrina I cropped.jpg|300px|''Sabrina I'' is a modern Handymax bulk carrier.]]
|Ship caption=''Sabrina I'' is a modern Handymax bulk carrier.
}}
{{Infobox ship class overview
|Name=
|Builders=
|Operators=
|Class before=
|Class after=
|Subclasses=[[Handymax]], [[Handysize]], [[Panamax]], [[Capesize]], [[Chinamax]]
|Cost=
|Built range={{circa|1850}}–present
|In service range=
|In commission range=
|Total ships building=
|Total ships planned=
|Total ships completed=
|Total ships cancelled=
|Total ships active=12,700 vessels over {{GT|500}} (2021)<ref>[https://static1.squarespace.com/static/5a4d1d26e5dd5b537a6647c5/t/620a7242f6e5160f2f81729a/1644851779148/BDRY+Primer+2022.pdf Dry Bulk Market Primer]</ref>
|Total ships laid up=
|Total ships lost=
|Total ships retired=
|Total ships preserved=
}}
{{Infobox ship characteristics
|Hide header=
|Header caption= (typical)
|Ship class=
|Ship type=Bulk carrier
|Ship tonnage=up to {{DWT|400,000}}
|Ship displacement=
|Ship length= {{convert|300|m|ft|abbr=on}}
|Ship beam=
|Ship height= {{convert|40|m|ft|abbr=on}}
|Ship draft=
|Ship depth=
|Ship decks=
|Ship ramps=
|Ship ice class=
|Ship power=
|Ship propulsion=2-stroke diesel engine and 1 propeller
|Ship speed=12 knots
|Ship range=
|Ship endurance=
|Ship boats=
|Ship capacity=
|Ship complement=
|Ship crew=
|Ship notes=Rear house, full hull, series of large hatches
}}
{{Infobox ship image
|Ship image=[[File:Bulk carrier general arrangement english.png|300px|Plans of a geared Hanydymax bulk carrier]]
|Ship caption=Plans of a geared Handymax bulk carrier
}}
|}{{multiple image
 | align = right
 | direction = vertical
 | width1 = 300
 | image1 = Grain bulk carrier & docks, Seattle.jpg
 | caption1 = Bulk carrier and loading apparatus, [[Seattle]] (2010)                    
 | image2 = Gladstone_branch_Dock_1.jpg
 | width2 = 300
 | caption2 = Bulk carriers in the [[Port of Liverpool]] (2018)
 | image3 = Federal Margaree (2005).jpg
 | width3 = 300
 | caption3 = ''Federal Margaree'' on the [[Great Lakes]] (2005)
}}
<!-- 1 Definition -->A '''bulk carrier''' or '''bulker''' is a [[merchant ship]] specially [[naval architecture|designed]] to transport unpackaged [[bulk cargo]]—such as [[Grain trade|grain]], coal, [[ore]], steel coils, and cement—in its [[cargo hold]]s. <!-- 2 History-->Since the first specialized bulk carrier was built in 1852, economic forces have led to increased size and sophistication of these ships. <!-- 5 Architecture--><!-- 5.1 Machinery--><!-- 5.3 Hull-->Today's bulk carriers are specially designed to maximize capacity, safety, efficiency, and durability.

<!-- 3 Modern bulk carriers-->Today, bulk carriers make up 21 percent of the world's merchant fleets,<ref>{{Cite web|date=2019-12-22|title=• Global merchant fleet - number of ships by type 2019 {{!}} Statista|url=https://www.statista.com/statistics/264024/number-of-merchant-ships-worldwide-by-type/|access-date=2021-03-29|archive-url=https://web.archive.org/web/20191222052736/https://www.statista.com/statistics/264024/number-of-merchant-ships-worldwide-by-type/|archive-date=22 December 2019}}</ref> <!-- 3.1 Size categories-->and they range in size from single-hold mini-bulk carriers to mammoth ore ships able to carry 400,000&nbsp;[[deadweight tonnage|metric tons of deadweight]] (DWT). <!-- 3.2 General types-->A number of specialized designs exist: some can unload their own cargo, some depend on port facilities for unloading, and some even package the cargo as it is loaded. <!-- 3.3 Today's fleet-->Over half of all bulk carriers have Greek, Japanese, or Chinese owners, and more than a quarter are registered in [[Panama]]. [[South Korea]] is the largest single builder of bulk carriers, and 82 percent of these ships were built in Asia.

<!-- 4.2 Voyages-->On bulk carriers, crews are involved in operation, management, and maintenance of the vessel, taking care of safety, navigation, maintenance, and cargo care, in accordance with international maritime legislation. Crews can range in size from three people on the smallest ships to over 30 on the largest.

Cargo loading operations vary in complexity, and loading and discharging of cargo can take several days. Bulk carriers can be gearless (dependent upon terminal equipment) or geared (having cranes integral to the vessel). <!-- 4 Operation--><!-- 4.1 Crew-->

<!-- 5.3 Hull-->Bulk cargo can be very dense, corrosive, or abrasive. This can <!-- 6 Safety--><!-- 6.1 Stability problems-->present safety problems that can threaten a ship: problems such as [[weight distribution|cargo shifting]], [[spontaneous combustion]], and cargo saturation. <!-- 6.2 Structural problems-->The use of old ships that have corrosion problems—as well as the bulk carriers' large hatchways—have been linked to a spate of bulk carrier sinkings in the 1990s<!-- 5.2 Hatches-->. These large hatchways, important for efficient cargo handling, can allow the entry of large volumes of water in storms and accelerate sinking once a vessel has [[Ship stability|listed]] or [[Angle of list|heeled]].<!-- 6.3 Crew safety--> New international regulations have since been introduced to improve ship design and inspection and to streamline the process for crews to abandon ship.

== Definition ==
[[File:Bulk_carrier_midship_section-i18.svg|alt=|border|right|frameless]]
The term bulk carrier has been defined in varying ways. As of 1999, the [[International Convention for the Safety of Life at Sea]] defines a bulk carrier as "a ship constructed with a single deck, top side tanks and hopper side tanks in cargo spaces and intended to primarily carry dry cargo in bulk; an ore carrier; or a combination carrier."<ref name="abs">{{cite web |url= http://www.eagle.org/regulatory/regupdate/msc70/bulk.html|title= Maritime Safety Committee's 70th Session, January 1999|access-date=2007-04-09 | work=American Bureau of Shipping |archive-url = https://web.archive.org/web/20070904190443/http://www.eagle.org/regulatory/regupdate/msc70/bulk.html |archive-date = 4 September 2007|url-status=dead}}</ref> Most [[Classification society|classification societies]] use a broader definition, by which a bulk carrier is any ship that carries dry unpackaged goods.<ref name="SNAME"/> [[Cargo ship|Multipurpose cargo ships]] can carry bulk cargo, but can also carry other cargoes and are not specifically designed for bulk carriage. The term "dry bulk carrier" is used to distinguish bulk carriers from bulk liquid carriers such as [[oil tanker|oil]], [[chemical tanker|chemical]], or [[tanker (ship)|liquefied petroleum gas carriers]].  Very small bulk carriers are almost indistinguishable from general cargo ships, and they are often classified based more on the ship's use than its design.

A number of abbreviations are used to describe bulk carriers. "[[Ore-bulk-oil carrier|OBO]]" describes a bulk carrier that carries a combination of ore, bulk, and oil, and "O/O" is used for combination oil and ore carriers.<ref>{{cite web |url=http://www.trans-inst.org/seawords.htm#o |title=Maritime Glossary |access-date=2008-05-06 |work=The Transportation Institute |archive-url = https://web.archive.org/web/20080415134847/http://www.trans-inst.org/seawords.htm#o |archive-date = 15 April 2008}}</ref> The terms "VLOC", "VLBC", "ULOC", and "ULBC" for very large and ultra-large ore and bulk carriers were adapted from the [[supertanker]] designations very large crude carrier and ultra-large crude carrier.<ref name="vlcc">{{cite web|url=http://www.nautinst.org/info/acrnm_abbrev.htm |title=Acronyms and Abbreviations |access-date=2007-04-12 |work=The Nautical Institute |archive-url=https://web.archive.org/web/20070408154846/http://www.nautinst.org/info/acrnm_abbrev.htm |archive-date=8 April 2007 |url-status=dead }}</ref>

== History ==
[[File:Venore as Charles G. Black.jpg|thumb|[[SS Venore|SS ''Venore'']] in 1926 as ''Charles G. Black'', which carried [[iron ore]] from [[Presidential Republic (1925–1973)|Chile]] to [[Maryland]].]]
Before specialized bulk carriers were developed, shippers had two methods to move bulk goods by ship. In the first method, [[longshoremen]] loaded the cargo into sacks, stacked the sacks onto [[pallet]]s, and put the pallets into the cargo hold with a [[Crane (machine)|crane]].<ref name="un"/> The second method required the shipper to charter an entire ship and spend time and money to build plywood bins into the holds.<ref name="halyer5-13"/> Then, to guide the cargo through the small hatches, wooden feeders and shifting boards had to be constructed.<ref name="halyer5-13">Hayler, 2003:5–13.</ref> These methods were slow and [[Labor intensity|labor-intensive]]. As with the [[container ship]], the problem of efficient loading and unloading has driven the evolution of the bulk carrier.{{citation needed|date=November 2015}}

[[File:Bulk carrier ship view from top.jpg|thumb|alt=Bulk carrier ship view from top by findseajobs.com|Bulk carrier ship]]

Specialized bulk carriers began to appear as [[steamship|steam-powered ships]] became more popular.<ref name="un">{{cite web |url=http://www.oceansatlas.com/unatlas/issues/safety_at_sea/bulk_carrier/bulk_carrier.htm |title=Bulk Carrier – Improving Cargo Safety |access-date=2007-04-09 |work=United Nations Atlas of the Oceans |archive-url=https://web.archive.org/web/20070927063932/http://www.oceansatlas.com/unatlas/issues/safety_at_sea/bulk_carrier/bulk_carrier.htm |archive-date=27 September 2007 |url-status=dead }}</ref> The first steam ship recognized as a bulk carrier was the British [[Collier (ship)|collier]] ''[[John Bowes (steamship)|John Bowes]]'', built in 1852.<ref name="Duron">Bruno-Stéphane Duron, {{DOClink|''[http://junon.u-3mrs.fr/ad210w00/memoires/99/m99dubr.doc Le Transport maritime des céréales]''}}, mémoire de DESS, 1999.</ref><ref name="ship1911">{{cite EB1911 |volume=24 |wstitle=Ship |page=881}}</ref> She featured a metal [[Hull (watercraft)|hull]], a [[steam engine]], and a [[Ballast tank|ballasting system]] which used seawater instead of sandbags.<ref name="Duron"/> These features helped her succeed in the competitive British coal market.<ref name="Duron"/> The first [[self-unloader]] was the [[lake freighter]] ''Hennepin'' in 1902 on the [[Great Lakes]]. This greatly decreased the unloading time of bulk carriers by using conveyor belt to move the cargo.<ref>[https://web.archive.org/web/20110715064416/http://www.perryballard.com/pdfs/curriculum_guide.pdf Shipwrecks – A Deep Look, The Rise of the Self-unloading Freighter], The Heritage Museum and Cultural Center
(HMCC) and Michigan Shipwreck Research Associates</ref> The first bulk carriers with [[Diesel engine|diesel propulsion]] began to appear in 1911.<ref name="Duron"/><ref name="ship1911"/>

Before [[World War II]], the international shipping demand for bulk products was low—about 25&nbsp;million tons for metal ores<ref name="imo1">International Maritime Organization, 1999:1.</ref><ref name="unbc">{{cite web |url=http://www.oceansatlas.org/unatlas/uses/transportation_telecomm/maritime_trans/shipworld/cargo_car/bulk/bulk_carriers.htm |title=Bulk Carriers |access-date=2007-04-12 |work=United Nations Ocean Atlas |archive-url=https://web.archive.org/web/20070513173307/http://www.oceansatlas.org/unatlas/uses/transportation_telecomm/maritime_trans/shipworld/cargo_car/bulk/bulk_carriers.htm |archive-date=13 May 2007 |url-status=dead }}</ref>—and most of this trade was [[coastal]].<ref name="reflets imo">{{cite web |url=http://www.imo.org/includes/blastDataOnly.asp/data_id%3D7987/BULK99.FIN.pdf |title=IMO and the safety of bulk carriers |access-date=2007-04-09 |work=International Maritime Organization |archive-url=https://wayback.archive-it.org/all/20080414073549/http://www.imo.org/includes/blastDataOnly.asp/data_id=7987/BULK99.FIN.pdf |archive-date=14 April 2008 |url-status=dead }}</ref> However, on the Great Lakes, bulk carriers hauled vast amounts of iron ore from Minnesota and Michigan's northern mines to the steel mills. In 1929, 73&nbsp;million tons of iron ore was transported on the Lakes, and an almost equal amount of coal, limestone, and other products were also moved.<ref>{{cite book|author=Mark L. Thompson|title=Steamboats & Sailors of the Great Lakes|url=https://books.google.com/books?id=KRLZDXIEWCsC&pg=PA26|year=1991|publisher=Wayne State University Press|isbn=0-8143-2359-6|page=26}}</ref> Two defining characteristics of bulk carriers were already emerging: the [[double bottom]], which was adopted in 1890,<ref name="Duron"/> and the triangular structure of the ballast tanks, which was introduced in 1905.<ref name="Duron"/> After World War II, an international bulk trade began to develop among [[industrialized nation]]s, particularly between the European countries, the United States and Japan.<ref name="imo1"/> Due to the economics of this trade, ocean bulk carriers became larger and more specialized.<ref name="unbc"/><ref name="imo1-2">International Maritime Organization, 1999: 1, 2.</ref> In this period, Great Lakes freighters increased in size, to maximize economies of scale, and self-unloaders became more common to cut [[turnaround time]]. The thousand-footers of the Great Lakes fleets, built in the 1970s, were among the longest ships afloat, and, in 1979, a record 214&nbsp;million tons of bulk cargo were moved on the Great Lakes.<ref>{{cite book|author=Mark L. Thompson|title=Steamboats & Sailors of the Great Lakes|url=https://books.google.com/books?id=KRLZDXIEWCsC&pg=PA26|year=1991|publisher=Wayne State University Press|isbn=0-8143-2359-6|page=28}}</ref>

== Categories ==

=== Size categories ===
<!--NOTE: The numbers in this table are cited. This means they have a footnote
 which points to a reference below from which the number came. If you
 feel a strong urge to change one of the numbers, please find a reliable
 source and place an appropriate footnote. -->
{| class="wikitable sortable mw-collapsible mw-collapsed" style="float:right;width:300px;font-size:8pt; margin-left:15px"
|+ Major bulk carrier size categories
|- style="background:#CCCCCC;" align="center"
!Name
!Size in<br />DWT<ref>Ranges vary slightly. MAN Diesel Group 2005, p.4. UNCTAD 2006, p. xii.</ref>
!Ships<ref name="bulkton">From Lamb, 2003 and the 2005 CIA World Factbook. See also [[:commons:Image:Bulk-carriers-by-deadweight-tonnage-2005.png|graph and table at Wikimedia Commons]].</ref>
!Traffic<ref>From Lamb, 2003. This is measured in terms of the tonnage of cargo carried multiplied by the distance traveled, and could be expressed in terms of (miles x tons), for example.</ref>
!New<br />price<ref>[http://www.unctad.org/en/Docs/rmt2011_en.pdf UNCTAD Review of Maritime Transport 2011] {{Webarchive|url=https://web.archive.org/web/20191211221051/https://unctad.org/en/docs/rmt2011_en.pdf |date=11 December 2019 }}, p. 81. Price for new vessel [[USD|$]] [[million|M]] in 2010.</ref>
!Used<br />price<ref>[http://www.unctad.org/en/Docs/rmt2011_en.pdf UNCTAD Review of Maritime Transport 2011] {{Webarchive|url=https://web.archive.org/web/20191211221051/https://unctad.org/en/docs/rmt2011_en.pdf |date=11 December 2019 }}, p. 82. Five (Ten for Handysize) year old ship in [[USD|$]] [[million|M]] in 2010.</ref>
|-
| valign="top" | [[Handysize]]
| valign="top" | 10,000 to 35,000
| valign="top" | 34%
| rowspan="2" valign="center" | 18%
| rowspan="2" valign="center" | $25M
| rowspan="2" valign="center" | $20M
|- valign="top"
|[[Handymax]]
| 35,000 to 59,000
| 37%
|- valign="top"
|[[Panamax]]
| 60,000 to 80,000
| 19%
| 20%
| $35M
| $25M
|- valign="top"
|[[Capesize]]
| 80,000 and over
| 10%
| 62%
| $58M
| $54M
|}
[[File:Capesize bulk carrier at Suez Canal Bridge.JPG|thumb|right|Post-deepening of the [[Suez Canal]], a [[capesize]] bulk carrier approaches the [[Egyptian-Japanese Friendship Bridge]]|313x313px]]
Bulk carriers are segregated into six major size categories: small, [[handysize]], [[handymax]], [[panamax]], [[capesize]], and very large.<ref name="mand">MAN Diesel Group, 2005, p. 3-4.</ref> Very large bulk and ore carriers fall into the capesize category but are often considered separately.

====Categories as per regions====
Categories occur in [[Intra Regional Trade|regional trade]], such as Kamsarmax,<ref>{{cite web |url=http://www.tsuneishi.co.jp/tess/factbook.html |title=Kamsarmax 82BC |access-date=2007-04-12 |work=Tsuneishi Corp. |archive-url=https://web.archive.org/web/20070706233111/http://www.tsuneishi.co.jp/tess/factbook.html |archive-date=6 July 2007 |url-status=dead }}</ref> [[Seawaymax]], Setouchmax, Dunkirkmax, and Newcastlemax also appear in regional trade.<ref name="mand"/>
* "'''Kamsarmax": '''Maximum [[length overall]] 229 meters refers to a new type of ship, larger than [[panamax]], that is suitable for berthing at the [[Kamsar|Port of Kamsar]] ([[Guinea|Republic of Guinea]]), where the major loading terminal of [[bauxite]] is restricted to vessels not more than 229 meters.<ref>Kamsarmax, ''[[Definition, World Shipping Directory]] (accessed August) 2013''</ref>
* '''"Newcastlemax"''': Maximum beam 50 meters, and maximum length overall of 300 meters Refers to the largest vessel able to enter the [[port of Newcastle]], Australia at about 185,000 DWT<ref>Steve's Guide to Bulk Carriers ''(Accessed August 2013), Harris, Steve, [www.stevesmaritime.com''</ref>
* '''"Setouchmax'''": About 203,000 [[Deadweight tonnage|DWT]], being the largest vessels able to navigate the [[Setouchi Sea]], Japan
* '''"Seawaymax"''': [[Length overall|LOA]] 226 m max /  7.92 m draft. Refers to the largest vessel that can pass through the canal locks of the [[St. Lawrence Seaway]] (Great Lakes, Canada)<ref>{{cite web |url=http://shiptradehouse.com/en/seawaymax |title=Seawaymax |access-date=11 December 2018 |archive-url=https://web.archive.org/web/20170701020039/http://shiptradehouse.com/en/seawaymax |archive-date=1 July 2017 |url-status=dead }}</ref>
* '''"Malaccamax"''': LOA 330 m / 20 m draft / 300,000 DWT, Refers to the largest vessel that can pass through the [[Straits of Malacca]].
* '''"Dunkirkmax"''': Maximum allowable [[Beam (nautical)|beam]] = 45 m / LOA 289 m. max (175,000 DWT approx) for the eastern harbour [[Lock gate|lock]] in the Port of [[Dunkirk]] (France)

Mini-bulk carriers are prevalent in the category of small vessels with a capacity of under {{DWT|10,000}}. Mini-bulk carriers carry from 500 to 2,500&nbsp;tons, have a single hold, and are designed for [[river]] transport. They are often built to be able to pass under [[bridge]]s and have small crews of three to eight people.

Handysize and Handymax ships are general purpose in nature.<ref name="SNAME">Lamb, 2003.</ref> These two segments represent 71% of all bulk carriers over {{DWT|10,000}} and also have the highest rate of growth.<ref name="NA 0106">{{cite journal
 |date=January 2006
 | title = Handysize re-vamp: the next move in bulk carriers?
 | journal =The Naval Architect
 }}</ref> This is partly due to new regulations coming into effect which put greater constraints on the building of larger vessels.<ref name="NA 0106"/> Handymax ships are typically 150–200&nbsp;m in length and 52,000{{spaced ndash}}{{DWT|58,000}} with five cargo holds and four cranes.<ref name="SNAME"/> These ships are also general purpose in nature.<ref name="SNAME"/>

The size of a Panamax vessel is limited by the [[Panama Canal Locks|Panama canal's lock chambers]], which can accommodate ships with a beam of up to 32.31&nbsp;m, a length overall of up to 294.13&nbsp;m, and a draft of up to 12.04&nbsp;m.<ref>Autoridad del Canal de Panamá 2005, pp. 11{{spaced ndash}}12.</ref>

Capesize ships are too large to traverse the Panama canal and must round [[Cape Horn]] to travel between the Pacific and Atlantic oceans. Earlier, Capesize ships could not traverse the [[Suez Canal|Suez]] and needed to go around the [[Cape of Good Hope]]. Recent deepening of the Suez canal to 66&nbsp;ft (20&nbsp;m) permits most Capesize ships to pass through it.<ref>{{cite web |url=https://af.reuters.com/article/idAFJOE66P09P20100726 |archive-url=https://web.archive.org/web/20120119101337/http://af.reuters.com/article/idAFJOE66P09P20100726 |url-status=dead |archive-date=19 January 2012 |title=Egypt's Suez canal H1 revenue, traffic up; upgrade helps |date=26 July 2010 |work=Reuters Africa |publisher= Thomson Reuters (af.reuters.com) |access-date=26 March 2011}}</ref>

Capesize bulk carriers are specialized: 93% of their cargo is iron ore and coal.<ref name="SNAME"/> Some ships on the [[Great Lakes Waterway]] exceed Panamax dimensions but they are limited to use on the Great Lakes as they cannot pass through the smaller [[St. Lawrence Seaway]] to the ocean. Very large ore carriers and very large bulk carriers are a subset of the capesize category reserved for vessels over {{DWT|200,000}}.<ref name="mand"/> Carriers of this size are almost always designed to carry iron ore.<ref name="mand"/>

In October 2022, Mitsui O.S.K. Lines (MOL)'s bulk carrier ''Shofu Maru'' arrived in [[Newcastle, New South Wales|Newcastle]] on its maiden voyage, becoming the first bulk carrier to be partially powered by hard sail wind power propulsion technology. A five percent fuel savings was anticipated.<ref>{{Cite web |last=Tamim |first=Baba |date=2022-10-28 |title='Wind Challenger': World's first partially wind-powered cargo ship successfully sailed |url=https://interestingengineering.com/transportation/worlds-first-wind-powered-cargo-carrier |access-date=2022-11-01 |website=interestingengineering.com |language=en-US}}</ref>

{{clear}}

=== General types ===
{| class="wikitable"
|+General Bulk Carrier Types
! Illustration !! Description
|- valign="top"
|[[File:Bulk carrier arriving in port.jpg|150px]]
|'''Geared bulk carriers''' are typically in the handysize to handymax size range although there are a small number of geared panamax vessels, like all bulk carriers they feature a series of holds covered by prominent hatch covers. They have [[Crane (machine)|cranes]], [[derrick]]s or [[conveyor]]s that allow them to load or discharge cargo in [[port]]s without shore-based equipment. This gives geared bulk carriers flexibility in the cargoes they can carry and the routes they can travel. (Photo: A typical geared handysize bulk carrier.)
|- valign="top"
|[[File:Maya OBO carrier 2.jpg|150px]]
|'''[[Ore-bulk-oil carrier|Combined carriers]]''' are designed to transport both liquid and dry bulk cargoes. If both are carried simultaneously, they are segregated in separate holds and tanks. Combined carriers require special design and are expensive. They were prevalent in the 1970s, but their numbers have dwindled since 1990. (Photo: The oil pipeline and dry bulk hold aboard ''Maya''.)
|- valign="top"
|[[File:Berge Athene.jpg|150px]]
|'''Gearless carriers''' are bulk carriers without cranes or conveyors. These ships depend on shore-based equipment at their ports of call for loading and discharging. They range across all sizes, the larger bulk carriers (VLOCs) can only dock at the largest ports, some of these are designed with a single port-to-port trade in mind. The use of gearless bulk carriers avoids the costs of installing, operating, and maintaining cranes. (Photo: ''Berge Athen'', a 225,000&nbsp;ton gearless bulk carrier.)
|- valign="top"
|[[File:Welland canal john b aird.JPG|150px]]
|'''[[Self-discharger]]s''' are bulk carriers with [[conveyor belt]]s, or with the use of an [[excavator]] that is fitted on a traverse running over the vessel's entire hatch, and that is able to move sideways as well. This allows them to discharge their cargo quickly and efficiently. (Photo: ''John B. Aird'' a self-discharging [[lake freighter]].)
|- valign="top"
|[[File:Edward L Ryerson Welland Canal 2008.JPG|150px]]
|'''[[Lake freighter|Lakers]]''' are the bulk carriers prominent on the [[Great Lakes]], often identifiable by having a forward [[superstructure|house]] that helps in transiting [[Lock (water transport)|locks]]. Operating in fresh water, these ships suffer much less [[corrosion]] damage and have a much longer lifespan than saltwater ships.<ref name="imo6">International Maritime Organization, 1999:6.</ref> As of 2005, there were 98 lakers of {{DWT|10,000}} or over.<ref name="s1"/> (Photo: ''Edward L. Ryerson'', a Great Lakes bulk carrier.)
|- valign="top"
|[[File:Brosen chl innovator.jpg|150px]]
|'''BIBO''' or '''"Bulk In, Bags Out"''' bulk carriers are equipped to bag cargo as it is unloaded. ''CHL Innovator'', shown in the photo, is a BIBO bulk carrier. In one hour, this ship can unload 300&nbsp;tons of bulk sugar and package it into 50&nbsp;kg sacks<ref>{{cite web |url=http://www.biboships.com/ |title=BIBO – Bulk In – Bags Out – Bulk In – Bulk Out |website=biboships.com |access-date=27 February 2017 |archive-date=26 September 2019 |archive-url=https://web.archive.org/web/20190926051609/http://biboships.com/ |url-status=dead }}</ref>
|}

== Fleet characteristics ==
[[Image:Number of bulkers graphic.svg|thumb|right|Growth of bulk carrier deadweight tonnage in green and percentage of bulk carriers to the entire fleet in red, from 1977 to 1999<ref>{{cite book| title=Lloyd's Register World Fleet Statistics Tables| year=2000| publisher=Lloyd's| location=London| url=http://www.lrfairplay.com| url-status=dead| archive-url=https://web.archive.org/web/20100106085401/http://www.lrfairplay.com/| archive-date=6 January 2010}}</ref>]]
The world's bulk transport has reached immense proportions: in 2005, 1.7&nbsp;billion metric tons of coal, iron ore, grain, bauxite, and phosphate was transported by ship.<ref name="unctad0611">UNCTAD 2006, p.11.</ref> Today, the world's bulk carrier fleet includes 6,225&nbsp;ships of over 10,000&nbsp;DWT, and represent 40% of all ships in terms of tonnage and 39.4% in terms of vessels.<ref name="s1">Office of Data and Economic Analysis, 2006:1.</ref> Including smaller ships, bulk carriers have a total combined capacity of almost 346&nbsp;million DWT.<ref name="unctad0621">UNCTAD 2006, p. 21.</ref> Combined carriers are a very small portion of the fleet, representing less than 3% of this capacity.<ref name="unctad0621"/> The [[lake freighter]]s of the [[Great Lakes]], with 98 ships of 3.2&nbsp;million total DWT, despite forming a small fraction of the total fleet by tonnage and only operating 10 months a year, carried a tenth of the world's bulk cargo because of the short trip distance and fast turnarounds.<ref name="s1"/><ref>[http://www.lre.usace.army.mil/ETSPubs/HFS/Great%20Lakes%20Navigation-Economic%20Strength%20to%20the%20Nation.pdf Great Lakes Navigation System: Economic Strength to the Nation] {{webarchive|url=https://web.archive.org/web/20110718041740/http://www.lre.usace.army.mil/ETSPubs/HFS/Great%20Lakes%20Navigation-Economic%20Strength%20to%20the%20Nation.pdf |date=18 July 2011 }}, US Army Corps of Engineers, 2006</ref>

As of 2005, the average bulk carrier was just over 13 years old.<ref name="unctad0623"/> About 41% of all bulk carriers were less than ten years old, 33% were over twenty years old, and the remaining 26% were between ten and twenty years of age.<ref name="unctad0623">UNCTAD 2006, p. 23.</ref> All of the 98 bulk carriers registered in the Great Lakes trade are over 20 years old and the oldest still sailing in 2009, the [[SS St. Marys Challenger|St. Mary's Challenger]], was 106 years old.<ref name="s3">Office of Data and Economic Analysis, 2006:2.</ref>
{{clear}}
[[Image:bulkers-flag-state-map-with-top-10.svg|thumb|right|Bulk carriers by flag state<ref name="cia05">{{cite web |url=https://www.cia.gov/library/publications/the-world-factbook/ |title=The CIA World Factbook, 2005 |access-date=2007-04-09 |work=cia.gov |archive-date=10 May 2013 |archive-url=https://web.archive.org/web/20130510200259/https://www.cia.gov/library/publications/the-world-factbook/ |url-status=dead }}</ref> [[:File:Oil-tankers-map-with-top-10.svg|(source data)]]|402x402px]]

=== Flag states ===
As of 2005, the [[United States Maritime Administration]] counted 6,225&nbsp;bulk carriers of {{DWT|10,000}} or greater worldwide.<ref name="s6">Office of Data and Economic Analysis, 2006:6.</ref> More bulk carriers are registered in [[Panama]], with 1,703&nbsp;ships, more than any four other [[flag state]]s combined.<ref name="s6"/> In terms of the number of bulk carriers registered, the top five flag states also include [[Ship registration in Hong Kong|Hong Kong]] with 492 ships, Malta (435), Cyprus (373), and China (371).<ref name="s6"/> Panama also dominates bulk carrier registration in terms of [[deadweight tonnage]]. Positions two through five are held by Hong Kong, Greece, Malta, and Cyprus.<ref name="s6"/>

=== Largest fleets ===
Greece, Japan, and China are the top three owners of bulk carriers, with 1,326, 1,041, and 979 vessels respectively.<ref name="s4">Office of Data and Economic Analysis, 2006:4.</ref> These three nations account for <!--redundant 3,346 vessels or!--> over 53% of the world's fleet.<ref name="s4"/>

Several companies have large private bulk carrier fleets. The multinational company [[Gearbulk Holding Ltd.]] has over 70&nbsp;bulk carriers.<ref>{{cite web |url=http://www.gearbulk.com/company.aspx |title=About Us |access-date=2008-04-22 |author=Gearbulk |year=2008 |publisher=Gearbulk Holding Limited |url-status=dead |archive-url=https://web.archive.org/web/20080423095144/http://www.gearbulk.com/company.aspx |archive-date=23 April 2008 }}</ref> [[The Fednav Group]] in Canada operates a fleet of over 80&nbsp;bulk carriers, including two designed to work in Arctic ice.<ref>{{cite web|url=http://www2.fednav.com/anglais/fleetowned.html |title=Fleet Owned |access-date=2008-04-21 |author=Fednav Group |year=2007 |publisher=Fednav Group |archive-url=https://web.archive.org/web/20080420031715/http://www2.fednav.com/anglais/fleetowned.html |archive-date=20 April 2008 |url-status=dead }} and {{cite web|url=http://www2.fednav.com/anglais/fleetchartered.html |title=Fleet Chartered |access-date=2008-04-21 |author=Fednav Group |year=2007 |publisher=Fednav Group |archive-url=https://web.archive.org/web/20080324185502/http://www2.fednav.com/anglais/fleetchartered.html |archive-date=24 March 2008 |url-status=dead }}</ref> [[Croatia]]'s [[Atlantska Plovidba d.d.]] has a fleet of 14&nbsp;bulk carriers.<ref>{{cite web |url=http://www.atlant.hr/fleet/fleet.html |title=Atlantska Plovidba Fleet |access-date=2007-04-15 |work=Atlantska Plovidba d.d. Dubrovnik.|archive-url = https://web.archive.org/web/20070407070302/http://www.atlant.hr/fleet/fleet.html |archive-date = 7 April 2007|url-status=dead}}</ref> The [[H. Vogemann Group]] in [[Hamburg, Germany]] operates a fleet of 19&nbsp;bulk carriers.<ref>{{cite web |url=http://www.vogemann.de/cms/upload/download_pdf/fleetlist.pdf |archive-url=https://wayback.archive-it.org/all/20080530021755/http://www.vogemann.de/cms/upload/download_pdf/fleetlist.pdf |url-status=dead |archive-date=2008-05-30 |title=Fleet List |access-date=2008-05-01 |author=H. Vogemann Group |year=2007 |publisher=H. Vogemann Group }}</ref> [[Portline]] in Portugal, owns 10 bulk carriers.<ref>{{cite web |url=http://www.portline.pt/ing_frota.htm |title=Portline Frota |access-date=2007-04-15 |work=PORTLINE Transportes Marítimos Internacionais, S.A.}}</ref> [[Dampskibsselskabet Torm]] in Denmark and Elcano in [[Spain]] also own notable bulk carrier fleets.<ref>According to [http://www.marine-marchande.net/Collection+Le+Mens/ALeMensAlpha.htm description of the main ship-owners], from the French Marine–Marchande website.{{dead link|date=February 2017|bot=medic}}{{cbignore|bot=medic}}</ref> Other companies specialize in mini-bulk carrier operations: England's [[Stephenson Clarke Shipping Limited]] owns a fleet of eight mini-bulk carriers and five small Handysize bulk carriers,<ref>{{cite web |url=http://www.scsbulk.com/fleet.php |title=Stephenson Clarke Fleet |access-date=2007-04-15 |work=Stephenson Clarke Shipping Ltd |archive-url=https://web.archive.org/web/20070401160549/http://www.scsbulk.com/fleet.php |archive-date=1 April 2007 |url-status=usurped }}</ref> and [[Cornships Management and Agency Inc.]] in [[Turkey]] owns a fleet of seven mini-bulk carriers.<ref>{{cite web |url=http://www.cornships.com/fleet.htm |title=The Cornships Fleet |access-date=2007-04-15 |work=Cornships Management & Agency Inc.}}</ref>

=== Builders ===
Asian companies dominate the construction of bulk carriers. Of the world's 6,225&nbsp;bulk carriers, <!--redundant 3,841 or!--> almost 62% were built in Japan<ref name="s5">Office of Data and Economic Analysis, 2006:5.</ref> by shipyards such as [[Oshima Shipbuilding]] and [[Sanoyas Hishino Meisho]].<ref name="SNAME"/> South Korea, with notable shipyards [[Daewoo]] and [[Hyundai Heavy Industries]],<ref name="SNAME"/> ranked second among builders, with 643&nbsp;ships. The People's Republic of China, with large shipyards such as Dalian, Chengxi, and Shanghai Waigaoqiao, ranked third, with 509&nbsp;ships.<ref name="s5"/> [[Taiwan]], with shipyards such as [[China Shipbuilding Corporation]],<ref name="SNAME"/> ranked fourth, accounting for 129&nbsp;ships.<ref name="s5"/> Shipyards in these top four countries built over 82% of the bulk carriers afloat.<ref name="s5"/>

=== Freight charges ===
[[File:Baltic Shipping Rates.png|thumb|Average time charter rates for bulk carriers|325x325px]]
Several factors affect the cost to move a bulk cargo by ship. The bulk freight market is very volatile, with the type of cargo, size of the vessel, and the route traveled all affecting the final price. Moving a capesize load of coal from South America to Europe cost anywhere from $15 to $25 per ton in 2005.<ref name="UNCTAD"/> Hauling a panamax-sized load of [[Aggregate (composite)|aggregate materials]] from the [[Gulf of Mexico]] to Japan that year could cost as little as $40 per ton to as much as $70 per ton.<ref name="UNCTAD"/>

Some shippers choose instead to [[Chartering (shipping)|charter]] a ship, paying a daily rate instead of a set price per ton.<ref name="UNCTAD"/> In 2005, the average daily rate for a Handymax ship varied between $18,000{{spaced ndash}}$30,000.<ref name="UNCTAD"/> A Panamax ship could be chartered for $20,000{{spaced ndash}}$50,000 per day, and a Capesize for $40,000{{spaced ndash}}$70,000 per day.<ref name="UNCTAD">UNCTAD 2005.</ref>

=== Ship breaking ===
{{Main| Ship breaking}}

Generally, ships are removed from the fleet by going through a process known as [[ship breaking]] or scrapping.<ref name="ilo-breaking">{{cite web |url=http://www.ilo.org/public/english/dialogue/sector/papers/shpbreak/index.htm |title=Is there a decent way to break up ships? |access-date=2007-05-29 |last=Bailey |first=Paul J. |year=2000 |work=Sectoral Activities Programme |publisher=International Labour Organization }}</ref> [[Ship-owner]]s and buyers negotiate scrap prices based on factors such as the ship's empty weight (called light ton displacement or LDT) and prices in the scrap metal market.<ref name="mtcp">{{cite book| author =Maritime Transport Coordination Platform| title =Tonnage Measurement Study| chapter-url =http://ec.europa.eu/transport/maritime/studies/doc/2006_11_tonnage_measurement_study.pdf| access-date =2007-05-29| series =MTCP Work Package 2.1, Quality and Efficiency| date =November 2006| location =Bremen/Brussels| page =3.3| chapter =3: The London Tonnage Convention| url-status =dead| archive-url =https://web.archive.org/web/20070330134300/http://ec.europa.eu/transport/maritime/studies/doc/2006_11_tonnage_measurement_study.pdf| archive-date =30 March 2007}}</ref> In 1998, almost 700&nbsp;ships were scrapped in places like [[Alang, India]] and [[Chittagong|Chittagong, Bangladesh]].<ref name="ilo-breaking"/> This is often done by 'beaching' the ship on open sand, then cutting it apart by hand with gas torches, a dangerous operation that results in injuries and fatalities, as well as exposure to toxic materials such as asbestos, lead, and various chemicals.<ref>

{{cite news
| url = https://www.thedailystar.net/news-detail-104585
| title = Safety still missing | date = 6 September 2009
| work = The Daily Star
| access-date = 2009-09-12
}}</ref><ref>

{{cite web
| url = http://www.osha.gov/SLTC/etools/shipyard/ship_breaking/survey_hm.html
| title = Shipbreaking » Inventory of Hazardous Materials
| access-date = 2009-09-12 | author = [[Occupational Safety and Health Administration|OSHA]] (US Govt)
}}</ref><ref>

{{cite web
| url = https://www.independent.co.uk/news/world/asia/alang-the-place-where-ships-go-to-die-1779656.html
| title = Alang: The place where ships go to die | date = 31 August 2009
| author =  Andrew Buncombe | access-date = 2009-09-12 | work = The Independent | location = UK}}

</ref> Half a million deadweight tons worth of bulk carriers were scrapped in 2004, accounting for 4.7% of the year's scrapping.<ref name="UNCTAD"/> That year, bulk carriers fetched particularly high scrap prices, between $340 and $350 per LDT.<ref name="UNCTAD"/>
{{clear}}

== Operation ==

=== Crew ===
{| class="wikitable" style="float:right;width:300px;font-size:8pt; margin-left:15px"
|+ Typical bulk carrier crew
| colspan="3" align="center" | '''[[Sea captain|Captain/Master]]'''
|-
! Deck<br />department !! Engine<br />department !! Steward's<br />department
|- valign="top"
|
1 [[Chief mate]]<br />
1 [[Second mate]]<br />
1 [[Third mate]]<br />
1 [[Boatswain]]<br />
1 [[Deck cadet]]<br />
2{{ndash}}6 [[Able seaman|Able seamen]]<br />
0{{ndash}}2 [[Ordinary seaman|Ordinary seamen]]
|
1 [[Chief engineer]]<br />
1 [[Second engineer]]<br />
1 [[Third engineer]]<br />
1{{ndash}}2 [[Fourth engineer]]s<br />
0{{ndash}}1 [[Electro-technical officer|ETO]]<br />
0{{ndash}}2 [[Motorman (ship)|Motormen]]<br />
1{{ndash}}3 [[Oiler (occupation)|Oilers]]<br />
0{{ndash}}3 Greasers<br />
1{{ndash}}3 [[Wiper (occupation)|Wipers]]
|
1 [[Chief steward]]<br />
1 [[Chief cook]] <br />
1 [[Steward's assistant]]
|}
The crew on a bulk carrier typically consists of 20 to 30&nbsp;people, though smaller ships can be handled by 8. The crew includes the captain or master, the [[deck department]], the [[engine department]], and the [[steward's department]]. The practice of taking [[passenger]]s aboard cargo ships, once almost universal, is very rare today and almost non-existent on bulk carriers.<ref>Some companies specialize in providing cruises on various kinds of freighters, for example [http://www.freighterworld.com/ Freighter World Cruises] {{Webarchive|url=https://web.archive.org/web/20070407160546/http://www.freighterworld.com/ |date=7 April 2007 }}.</ref>

During the 1990s, bulk carriers were involved in an alarming number of [[shipwreck]]s. This led ship-owners to commission a study seeking to explain the effect of various factors on the crew's effectiveness and competence.<ref name="TL">{{cite book
|last= Lane
|first= Tony
|title= Bulk Carrier Crews; Competence, Crew composition & Voyage Cycles
|year= 2001
|publisher= Cardiff University
}}</ref> The study showed that crew performance aboard bulk carriers was the lowest of all groups studied.<ref name="TL"/> Among bulk carrier crews, the best performance was found aboard younger and larger ships.<ref name="TL"/> Crews on better-maintained ships performed better, as did crews on ships where fewer languages were spoken.<ref name="TL"/>

Fewer [[deck officer]]s are employed on bulk carriers than on similarly sized ships of other types.<ref name="TL"/> A mini-bulk carrier carries two to three deck officers, while larger Handysize and Capesize bulk carriers carry four.<ref name="TL"/> [[LNG carrier|Liquid natural gas tankers]] of the same size have an additional deck officer and [[sailor|unlicensed mariner]].<ref name="TL"/>

=== Voyages ===
A bulk carrier's voyages are determined by market forces; routes and cargoes often vary. A ship may engage in the [[grain trade]] during the [[harvest]] season and later move on to carry other cargoes or work on a different route. Aboard a [[Coastal trading vessel|coastal carrier]] in the [[tramp trade]], the crew will often not know the next port of call until the cargo is fully loaded.

Because bulk cargo is so difficult to discharge, bulk carriers spend more time in port than other ships. A study of mini-bulk carriers found that it takes, on average, twice as much time to unload a ship as it does to load it.<ref name="TL"/> A mini-bulk carrier spends 55&nbsp;hours at a time in port, compared to 35&nbsp;hours for a lumber carrier of similar size.<ref name="TL" /> This time in port increases to 74&nbsp;hours for Handymax and 120&nbsp;hours for Panamax vessels.<ref name="TL"/> Compared with the 12-hour turnarounds common for container ships, 15-hour turnarounds for car carriers, and 26-hour turnarounds for large tankers, bulk carrier crews have more opportunities to spend time ashore.<ref name="TL" />
{{clear}}

=== Loading and unloading ===
Loading and unloading a bulk carrier is time-consuming and dangerous. The process is planned by the ship's [[chief mate]] under the direct and continued supervision of ship's [[captain (nautical)|captain]]. International regulations require that the captain and terminal master agree on a detailed plan before operations begin.<ref>{{cite web |url=http://www.imo.org/includes/blastDataOnly.asp/data_id%3D1836/947.pdf |title=MSC Circular 947: Safe Loading and Unloading of Bulk Carriers |access-date=2007-04-15 |work=International Maritime Organization |archive-url=https://web.archive.org/web/20070610160622/http://www.imo.org/includes/blastDataOnly.asp/data_id%3D1836/947.pdf |archive-date=10 June 2007 |url-status=dead }}</ref> [[Deck officer]]s and [[stevedore]]s oversee the operations. Occasionally loading errors are made that cause a ship to capsize or break in half at the pier.<ref>George, 2005:245.</ref>

The loading method used depends on both the cargo and the equipment available on the ship and on the dock.  In the least advanced ports, cargo can be loaded with shovels or bags poured from the hatch cover. This system is being replaced with faster, less labor-intensive methods.<ref name="packard">{{cite book
|last=Packard
|first= William V.
|title= Sea-trading
|year= 1985
|publisher= Fairplay Publications
}}</ref> [[Crane (machine)|Double-articulation cranes]], which can load at a rate of 1,000&nbsp;tons per hour, represent a widely used method,<ref name="packard"/> and the use of shore-based [[gantry crane]]s, reaching 2,000&nbsp;tons per hour, is growing.<ref name="packard"/> A crane's discharge rate is limited by the bucket's capacity (from 6 to 40&nbsp;tons) and by the speed at which the crane can take a load, deposit it at the terminal and return to take the next. For modern gantry cranes, the total time of the grab-deposit-return cycle is about 50&nbsp;seconds.<ref name="SNAME"/>

Conveyor belts offer a very efficient method of loading, with standard loading rates varying between 100 and 700&nbsp;tons per hour, although the most advanced ports can offer rates of 16,000&nbsp;tons per hour.<ref name="packard"/><ref name="imo7">International Maritime Organization, 1999:7.</ref> Start-up and shutdown procedures with conveyor belts, though, are complicated and require time to carry out.<ref name="imo7"/> Self-discharging ships use conveyor belts with load rates of around 1,000&nbsp;tons per hour.<ref name="packard"/>

Once the cargo is discharged, the crew begins to clean the holds. This is particularly important if the next cargo is of a different type.<ref name="halyer5-11">Hayler, 2003:5–11.</ref> The immense size of cargo holds and the tendency of cargoes to be physically irritating add to the difficulty of cleaning the holds. When the holds are clean, the process of loading begins.

It is crucial to keep the cargo level during loading in order to maintain stability.<ref name="halyer5-13" /> As the hold is filled, machines such as [[excavator]]s and [[bulldozer]]s are often used to keep the cargo in check. Leveling is particularly important when the hold is only partly full, since cargo is more likely to shift.<ref>George, 2005:341, 344.</ref> Extra precautions are taken, such as adding longitudinal divisions and securing wood atop the cargo.<ref name="un"/> If a hold is full, a technique called tomming is used,<ref name="halyer5-13"/> which involves digging out a {{convert|6|ft|m|0}} hole below the hatch cover and filling it with bagged cargo or weights.<ref name="halyer5-13"/>

<gallery mode="slideshow" showthumbnails="" caption="A typical bulk carrier offload">
Image:Bulldozer loaded on bulk carrier.jpg|'''1.''' A bulldozer is loaded into the hold.
Image:Bulker-unload-sequence-2.jpg|'''2.''' The bulldozer pushes cargo to the center of the hold.
Image:Velox cargo ship unloading rapeseed.jpg|'''3.''' The gantry crane picks up the cargo.
Image:Bulker-unload-sequence-4.jpg|'''4.''' The gantry crane removes the cargo from the ship.
Image:Grab unloaded into hopper.jpg|'''5.''' The gantry crane moves the cargo to a bin on the pier.
</gallery>

== Architecture ==
A bulk carrier's [[Naval architecture|design]] is largely defined by the cargo it will carry. The cargo's density, also known as its [[stowage factor]], is the key factor. Densities for common bulk cargoes vary from 0.6&nbsp;tons per cubic meter for light grains to 3&nbsp;tons per cubic meter for iron ore.<ref name="SNAME"/>

The overall cargo weight is the limiting factor in the design of an ore carrier, since the cargo is so dense. Coal carriers, on the other hand, are limited by overall volume, since most bulk carriers can be completely filled with coal before reaching their maximum draft.<ref name="SNAME"/>

For a given tonnage, the second factor which governs the ship's dimensions is the size of the ports and [[waterway]]s it will travel to. For example, a vessel that will pass the Panama Canal will be limited in its [[Beam (nautical)|beam]] and [[Draft (hull)|draft]]. For most designs, the ratio of length-to-width ranges between 5 and 7, with an average of 6.2.<ref name="SNAME"/> The ratio of length-to-height will be between 11 and 12.<ref name="SNAME"/>

=== Machinery ===
{{multiple image
| header = Examples of bulk carrier [[architectural plan]]s
| direction = vertical
| image1 = Capesize bulk carrier lines plan.svg
| width1 = 150
| caption1 = Line plan of a 1990 Capesize ore carrier.
| image2 = Bulk carrier midship section en.svg
| width2 = 150
| caption2 = Typical midship section of a bulk carrier with a single hull and double bottom.
| align = 
| total_width = 450
| alt1 = 
}}
The [[engine room]] on a bulk carrier is usually near the [[stern]], under the [[superstructure]]. Larger bulk carriers, from Handymax up, usually have a single [[Two-stroke cycle|two-stroke]] low-speed [[crosshead]] [[diesel engine]] directly coupled to a fixed-pitch [[propeller]]. Electricity is produced by auxiliary [[electrical generator|generators]] and/or an [[alternator]] coupled to the propeller shaft. On the smaller bulk carriers, one or two [[Four-stroke cycle|four-stroke]] diesels are used to turn either a fixed or [[Variable-pitch propeller (marine)|controllable-pitch propeller]] via a reduction [[gearbox]], which may also incorporate an output for an alternator.<ref name="SNAME"/> The average design ship speed for bulk carriers of Handysize and above is {{convert|13.5|-|15|kn}}.<ref name="mand"/> The propeller speed is relatively low, at about 90 revolutions per minute, although it depends on the size of the propeller.<ref name="SNAME"/>

As a result of the [[1973 oil crisis]], the [[1979 energy crisis]], and the resulting rise in oil prices, experimental designs using coal to fuel ships were tested in the late 1970s and early 1980s. The Australian National Lines (ANL) constructed two 74,700-ton coal-burner ships called ''River Boyne'' and ''River Embely''.<ref name="Ewart"/> along with two constructed by TNT called ''TNT Capricornia'' and ''TNT Capentaria'' and renamed ''Fitzroy River'' and ''Endeavor River''. These ships were financially effective for the duration of their lives, and their [[steam engine]]s were able to generate a shaft-power of {{convert|19000|hp}}.<ref name="Ewart"/> This strategy gave an interesting advantage to carriers of [[bauxite]] and similar fuel cargoes, but suffered from poor engine yield compared to higher maintenance cost and efficient modern diesels, maintenance problems due to the supply of ungraded coal, and high initial costs.<ref name="Ewart">{{cite book|last= Ewart|first= W.D.|title= Bulk Carriers|year= 1984|publisher= Fairplay Publications Ltd|isbn=0-905045-42-4 }}</ref>

=== Hatches ===
[[Image:Hatch covers on bulk carrier.jpg|left|thumb|The sliding hatchcovers of ''Zaira.'']]

A hatch or hatchway is the opening at the top of a [[hold (ship)|cargo hold]]. The mechanical devices which allow hatches to be opened and closed are called hatch cover. In general, hatch covers are between 45% and 60% of the ship's breadth, or beam, and 57% to 67% of the length of the holds.<ref name="SNAME"/> To efficiently load and unload cargo, hatches must be large, but large hatches present structural problems. Hull stress is concentrated around the edges of the hatches, and these areas must be reinforced.<ref name="imo7"/> Often, hatch areas are reinforced by locally increasing the [[scantling]]s or by adding structural members called stiffeners. Both of these options have the undesired effect of adding weight to the ship.

As recently as the 1950s, hatches had wooden covers that would be broken apart and rebuilt by hand, rather than opened and closed.<ref>Hayler, 2003:5–9.</ref> Newer vessels have hydraulic-operated metal hatch covers that can often be operated by one person.<ref name="halyer5-11"/> Hatch covers can slide forwards, backwards, or to the side, lift up or fold up. It is essential that the hatch covers be watertight: unsealed hatches lead to accidental cargo hold flooding, which has caused many bulk carriers to sink.<ref name="imo-imp"/>

Regulations regarding hatch covers have evolved since the investigation following the loss of the {{MV|Derbyshire}}.<ref>{{cite conference
 | first = David
 | last = Byrne
 | title = Hatch Covers on Bulk Carriers: The Effect on Procurement Costs of Changes in Design Pressure
| date = 10 October 2001
 | location = Conférence internationale RINA
}}</ref> The Load Line Conference of 1966 imposed a requirement that hatch covers be able to withstand load of 1.74&nbsp;tons/m<sup>2</sup> due to sea water, and a minimum scantling of 6&nbsp;mm for the tops of the hatch covers. The [[International Association of Classification Societies]] then increased this strength standard by creating its ''Unified Requirement S21''<ref name="ur21">International Association of Classification Societies 2007, p. 21-1.</ref> in 1998.  This standard requires that the pressure due to sea water be calculated as a function of freeboard and speed, especially for hatch covers located on the forward portion of the ship.<ref name="ur21"/>

=== Hull ===
[[File:CSL TECUMSEH.jpg|thumb|Unloaded [[Trillium-class freighter|''Trillium''-class dry bulk carrier]] at the Port of Redwood City]]
Bulk carriers are designed to be easy to build and to store cargo efficiently. To facilitate [[ship construction|construction]], bulk carriers are built with a single [[Hull (watercraft)|hull]] curvature.<ref name="SNAME"/> Also, while a [[bulbous bow]] allows a ship to move more efficiently through the water, designers lean towards simple vertical bows on larger ships.<ref name="SNAME"/> Full hulls, with large [[block coefficient]]s, are almost universal, and as a result, bulk carriers are inherently slow.<ref name="SNAME"/> This is offset by their efficiency. Comparing a ship's carrying capacity in terms of deadweight tonnage to its weight when empty is one way to measure its efficiency.<ref name="SNAME"/> A small Handymax ship can carry five times its weight.<ref name="SNAME"/> In larger designs, this efficiency is even more pronounced: Capesize vessels can carry more than eight times their weight.<ref name="SNAME"/>

Bulk carriers have a cross-section typical of most merchant ships. The upper and lower corners of the hold are used as [[ballast tank]]s, as is the [[double bottom]] area. The corner tanks are reinforced and serve another purpose besides controlling the ship's trim. Designers choose the angle of the corner tanks to be less than that of the [[angle of repose]] of the anticipated cargoes.<ref name="reflets imo"/> This greatly reduces side-to-side movement, or "shifting," of cargo which can endanger the ship.<ref name="reflets imo"/>

The double bottoms are also subject to design constraints. The primary concern is that they be high enough to allow the passage of pipes and cables. These areas must also be roomy enough to allow people safe access to perform surveys and maintenance. On the other hand, concerns of excess weight and wasted volume keep the double bottoms very tight spaces.

Bulk carrier hulls are made of steel, usually [[mild steel]].<ref>George, 2005:221.</ref> Some manufacturers have preferred high-tensile steel recently in order to reduce the tare weight.<ref name="iimo8">International Maritime Organization, 1999:8.</ref> However, the use of high-tensile steel for longitudinal and transverse reinforcements can reduce the hull's rigidity and resistance to corrosion.<ref name="reflets imo"/> Forged steel is used for some ship parts, such as the propeller shaft support.<ref name="SNAME"/> Transverse partitions are made of [[corrugated iron]], reinforced at the bottom and at connections.<ref name="SNAME"/> The construction of bulk carrier hulls using a [[concrete]]-steel sandwich has been investigated.<ref>{{cite journal
 |date=February 2005
 | title = Concrete sandwiches: structural strength and safety for bulk carriers
 | journal =The Naval Architect
 }}</ref>

[[Double hull]]s have become popular in the past ten years.<ref name="SNAME"/> Designing a vessel with double sides adds primarily to its breadth, since bulk carriers are already required to have [[double bottom]]s.<ref>{{cite web |url=http://www.imo.org/Safety/mainframe.asp?topic_id=69&doc_id=588 |archive-url=https://web.archive.org/web/20070926234721/http://www.imo.org/Safety/mainframe.asp?topic_id=69&doc_id=588 |url-status=dead |archive-date=2007-09-26 |title=New IMO bulk carrier regulations enter into force on 1 July 1999 |access-date=2007-04-10 |work=International Maritime Organization }}</ref> One of the advantages of the double hull is to make room to place all the structural elements in the sides, removing them from the [[cargo hold|holds]].<ref>{{cite journal
 |date=November 2005
 | title = NG-Bulk20: a new Turkish double-skin bulk carrier design
 | journal =The Naval Architect
 }}</ref> This increases the volume of the holds, and simplifies their structure which helps in loading, unloading, and cleaning.<ref>{{cite web |url=http://www.dnv.com/publications/classification_news/class_news_2003_02/Oshimalooksahead.asp |title=Oshima looks ahead |access-date=2007-04-15 |author=Det Norske Veritas |author-link=Det Norske Veritas |date=28 May 2003 |url-status=dead |archive-url=https://web.archive.org/web/20070214012150/http://www.dnv.com/publications/classification_news/class_news_2003_02/Oshimalooksahead.asp |archive-date=14 February 2007 }}</ref> Double sides also improve a ship's capacity for ballasting, which is useful when carrying light goods: the ship may have to increase its draft for stability or seakeeping reasons, which is done by adding ballast water.

A recent design, called Hy-Con, seeks to combine the strengths of single-hull and double-hull construction. Short for Hybrid Configuration, this design doubles the forward-most and rear-most holds and leaves the others single-hulled.<ref name="hycon">{{cite web |url=http://www.osy.co.jp/en/bc_lineup/hy-con.html |title=Oshima Hy-Con bulk carrier |access-date=2007-04-14 |work=Oshima Shipbuilding Co., Ltd. |archive-url = https://web.archive.org/web/20060430180139/http://www.osy.co.jp/en/bc_lineup/hy-con.html |archive-date = 30 April 2006}}</ref> This approach increases the ship's solidity at key points, while reducing the overall tare weight.<ref>{{cite web |url=http://www.osy.co.jp/en/bc_lineup/handymax.html |title="Ultra Handymax" Semi-Double Hull Handymax Bulk Carrier |access-date=2007-04-10 |work=Oshima Shipbuilding Co., Ltd. |archive-url = https://web.archive.org/web/20060430004211/http://www.osy.co.jp/en/bc_lineup/handymax.html |archive-date = 30 April 2006}}</ref>

Since the adoption of double hull has been more of an economic than a purely architectural decision, some argue that double-sided ships receive fewer comprehensive surveys and suffer more from hidden corrosion.<ref>{{cite book |url=http://books.nap.edu/openbook.php?record_id=5798&page=261 |title=Double-Hull Tanker Legislation: An Assessment of the Oil Pollution Act of 1990 (1998) |access-date=2007-04-10 |series=Marine Board Commission on Engineering and Technical Systems |doi=10.17226/5798 |year=1998 |isbn=978-0-309-06370-8 }}</ref> In spite of opposition, double hulls became a requirement for Panamax and Capesize vessels in 2005.<ref>{{cite journal
 |date=May 2003
 | title = Double-skin bulk carriers: paradise or problem?
 | journal =The Naval Architect
 }}</ref>

Freighters are in continual danger of "breaking their backs"<ref name="gstruct217">George, 2005:217.</ref> and thus longitudinal strength is a primary architectural concern. A [[naval architect]] uses the correlation between longitudinal strength and a set of hull thicknesses called [[scantling]]s to manage problems of longitudinal strength and stresses. A ship's hull is composed of individual parts called ''members.''<ref name="gstruct218">George, 2005:218.</ref> The set of dimensions of these members is called the ship's scantlings.<ref name="gstruct218"/> Naval architects calculate the stresses a ship can be expected to be subjected to, add in safety factors, and then can calculate the required scantlings.<ref name="gstruct218"/>

These analyses are conducted when traveling empty, loading and unloading, when partially and fully loaded, and under conditions of temporary overloading.<ref name="SNAME"/> Places subject to the largest stresses are studied carefully, such as hold-bottoms, hatch-covers, bulkheads between holds, and the bottoms of ballast tanks.<ref name="SNAME"/> Great Lakes bulk carriers also must be designed to withstand [[springing]], or developing [[resonance]] with the [[ocean surface wave|waves]], which can cause [[fatigue (material)|fatigue fractures]].<ref name="iimo8"/>

Since 1 April 2006, the International Association of Classification Societies has adopted the ''Common Structural Rules.'' The rules apply to bulk carriers more than 90&nbsp;meters in length and require that scantlings' calculations take into account items such as the effect of corrosion, the harsh conditions often found in the [[North Atlantic]], and dynamic stresses during loading. The rules also establish margins for corrosion, from 0.5 to 0.9&nbsp;mm.<ref name="NA 0306">{{cite journal
 |date=March 2006
 | title = Implications of commons structural rules
 | journal =The Naval Architect
 }}</ref>

== Safety ==
The 1980s and 1990s were a very unsafe time for bulk carriers. Many bulk carriers sank during this time; 99 were lost between 1990 and 1997 alone.<ref name="imo1"/> Most of these sinkings were sudden and quick, making it impossible for the crew to escape: more than 650 sailors were lost during this same period.<ref name="imo1"/> Due partly to the sinking of {{MV|Derbyshire}}, a series of international safety resolutions regarding bulk carriers were adopted during the 1990s.<ref name="imo-imp" />

=== Stability problems ===
Cargo shifting poses a great danger for bulk carriers. The problem is even more pronounced with grain cargoes, since grain settles during a voyage and creates extra space between the top of the cargo and the top of the hold.<ref name="un"/> Cargo is then free to move from one side of the ship to the other as the ship rolls. This can cause the ship to list, which, in turn, causes more cargo to shift. This kind of chain reaction can capsize a bulk carrier very quickly.<ref name="un"/>

The 1960 SOLAS Convention sought to control this sort of problem.<ref name="imo2">International Maritime Organization, 1999:2.</ref> These regulations required the upper ballast tanks designed in a manner to prevent shifting. They also required cargoes to be leveled, or trimmed, using excavators in the holds.<ref name="imo1-2"/><ref name="trimming">{{Cite book |last=Grunau |first=Peter |url=https://books.google.com/books?id=Q1ofCwAAQBAJ&dq='trimming+of+cargo%22&pg=PA120 |title=Cargo Handling and Stowage: A Guide for Loading, Handling, Stowage, Securing, and Transportation of Different Types of Cargoes, Except Liquid Cargoes and Gas |date=2015-12-03 |publisher=BoD – Books on Demand |isbn=978-3-7392-1757-4 |language=en}}</ref> The practice of trimming reduces the amount of the cargo's surface area in contact with air<ref name="imo4">International Maritime Organization, 1999:4.</ref> which has a useful side-effect: reducing the chances of spontaneous combustion in cargoes such as coal, iron, and metal shavings.<ref name="imo4"/>

Another sort of risk that can affect dry cargoes is absorption of ambient moisture.<ref name="kemp">{{cite book
|last=Kemp
|first= John F.
|title= Notes on Cargo Work
|year= 1971
|publisher= Kandy Publications
|edition=3rd
|isbn= 0-85309-040-8 }}</ref> When very fine concretes and aggregates mix with water, the mud created at the bottom of the hold shifts easily and can produce a [[free surface effect]].<ref name="kemp"/> The only way to control these risks is by good ventilation practices and careful monitoring for the presence of water.<ref name="kemp"/>

The [[International Maritime Organization]] sets out international standards and codes for the safe stowage and transportation of bulk carrier cargoes. These include the [[International Maritime Solid Bulk Cargoes Code]], the [[International Code for the Safe Carriage of Grain in Bulk]] and the [[Code of Safe Practice for Ships Carrying Timber Deck Cargoes]].<ref name="21stCentury646">{{cite book |date=2015 |title=21st Century Seamanship |location=Edinburgh |publisher=[[Witherby Publishing Group]] |page=646 |isbn=9781856096324}}</ref><ref name="21stCentury598">{{cite book |date=2015 |title=21st Century Seamanship |location=Edinburgh |publisher=[[Witherby Publishing Group]] |page=598-599 |isbn=9781856096324}}</ref>

=== Structural problems ===
[[File:Seledang Ayu.jpeg|center|600px|thumb|Diagram showing the wreck of {{MV|Selendang Ayu||2}}, and the double-bottom tank leaks.]]

In 1990 alone, 20 bulk carriers sank, taking with them 94 crewmen. In 1991, 24 bulk carriers sank, killing 154.<ref name="imo5">International Maritime Organization, 1999:5.</ref> This level of loss focused attention on the safety aspects of bulk carriers, and a great deal was learned. The [[American Bureau of Shipping]] concluded that the losses were "directly traceable to failure of the cargo hold structure"<ref name="imo6"/> and [[Lloyd's Register of Shipping]] added that the hull sides could not withstand "the combination of local corrosion, fatigue cracking and operational damage."<ref name="imo5"/>

The accident studies showed a clear pattern:<ref name="imo-imp">{{cite web|url = http://www.imo.org/en/OurWork/Safety/Regulations/Documents/BULK.pdf|title = Improving the safety of bulk carriers|access-date = 2015-11-02|work = International Maritime Organization|archive-date = 13 July 2017|archive-url = https://web.archive.org/web/20170713064541/http://www.imo.org/en/OurWork/Safety/Regulations/Documents/BULK.pdf|url-status = dead}}</ref>
# Sea water enters the forward hatch, due to a large wave, a poor seal, corrosion, etc.<ref name="imo-imp"/>
# The extra water weight in hold number one compromises the partition to hold number two,<ref name="imo-imp"/>
# Water enters hold number two and alters the trim so much that more water enters the holds<ref name="imo-imp"/>
# With two holds rapidly filling with water, the bow submerges, and the ship quickly sinks, leaving little time for the crew to react.<ref name="imo-imp"/>

Previous practices had required ships to withstand the flooding of a single forward hold but did not guard against situations where two holds would flood. The case where two after (rear) holds are flooded is no better, because the engine room is quickly flooded, leaving the ship without propulsion. If two holds in the middle of the ship are flooded, the stress on the hull can become so great that the ship snaps in two.

[[File:Seledang Ayu 2.jpeg|thumb|right|{{ship||Selendang Ayu}} suffered a catastrophic fracture in number 4 hold in December 2004.|218x218px]]

Other contributing factors were identified:
* Most shipwrecks involved ships over 20 years in age. A glut of ships of this age occurred in the 1980s, caused by an overestimate of the growth of international trade. Rather than replace them prematurely, shipping companies were compelled on cost grounds to keep their aging vessels in service.<ref name="un"/>
* Corrosion, due to a lack of maintenance, affected the seals of the hatch covers and the strength of the bulkheads which separate holds. The corrosion is difficult to detect due to the immense size of the surfaces involved.<ref>{{cite web |url=http://www.iacs.org.uk/fsa/wp5/main.htm |title=Formal Safety Assessment of Bulk Carriers, Fore-End Watertight Integrity' |access-date=2007-04-09 |work=International Association of Classification Societies |archive-url=https://web.archive.org/web/20070206175021/http://www.iacs.org.uk/fsa/wp5/main.htm
|archive-date=6 February 2007 }}</ref><ref name="imo5-6">International Maritime Organization, 1999:5,6.</ref>
* Advanced methods of loading were not foreseen when the ships were designed. While the new processes are more efficient, loading is more difficult to control (it can take over an hour just to halt the operation), occasionally resulting in overloading the ship. These unexpected shocks, over time, can damage the hull's structural integrity.<ref name="imo7"/>
* Recent use of high-tensile steel allows building a structure with less material and weight while retaining similar strength. However, because it is thinner than regular steel, HT steel can corrode more easily, plus it can develop metal fatigue in choppy seas.<ref name="iimo8"/>
* According to Lloyd's Register, a principal cause of sinkings was the attitude of ship-owners, who sent ships with known problems to sea.<ref name="imo7-8">International Maritime Organization, 1999:7,8.</ref>

The new rules adopted in the 1997 annexes to the [[Safety of Life at Sea|SOLAS]] convention focused on problems such as reinforcing bulkheads and the longitudinal frame, more stringent inspections (with a particular focus on corrosion) and routine in-port inspections.<ref name="un"/> The 1997 additions also required bulk carriers with restrictions (for instance, forbidden from carrying certain types of cargoes) to mark their hulls with large, easy-to-see triangles.<ref>{{cite web |url=http://www.eagle.org/regulatory/regupdate/msc71/bulk.html |title=Maritime Safety Committee's 71st Session, May 1999 |access-date=2007-04-10|work=American Bureau of Shipping |archive-url = https://web.archive.org/web/20070930043825/http://www.eagle.org/regulatory/regupdate/msc71/bulk.html |archive-date = 30 September 2007|url-status=dead}}</ref>

=== Crew safety ===
[[File:Rettungsboot2.jpg|left|thumb|Launch of a free-fall lifeboat.|406x406px]]
Since December 2004, Panamax and Capesize bulk carriers have been required to carry free-fall [[Lifeboat (shipboard)|lifeboats]] located on the stern, behind the deckhouse.<ref name="un"/> This arrangement allows the crew to abandon ship quickly in case of a catastrophic emergency.<ref>{{cite web |url = https://www.pbs.org/wgbh/nova/escape/pioship.html | title = Pioneers of Survival |access-date=2007-04-10 |work=NOVA }}</ref> One argument against the use of free-fall lifeboats is that the evacuees require "some degree of physical mobility, even fitness" to enter and launch the boat.<ref name="lb">{{cite web |url=http://www.maib.gov.uk/cms_resources/Review_of_%20lifeboat_and_launching_systems_accidents.pdf |title=Review of Lifeboat and Launching System Accidents |access-date=2007-04-10 |work=Marine Accident Investigation Branch }}</ref> Also, injuries have occurred during launches, for example, in the case of incorrectly secured safety belts.<ref name="lb"/>

In December 2002, Chapter XII of the SOLAS convention was amended to require the installation of high-level water alarms and monitoring systems on all bulk carriers. This safety measure quickly alerts watch standers on the bridge and in the engine room in case of flooding in the holds.<ref name="un"/> In cases of catastrophic flooding, these detectors could speed the process of abandoning ship.
{{clear}}

== See also ==
{{Portal|Transport}}
* [[MS Berge Stahl|''Berge Stahl'']], the largest bulk carrier from 1986 until 2011
* [[MV Bright Field|''Bright Field'']]
* [[SS Edmund Fitzgerald|''Edmund Fitzgerald'']]
* [[MV Flare|''Flare'']]
* [[MV Lake Illawarra|''Lake Illawarra'']]
* ''[[New Carissa]]''
* [[MS Ore Brasil|''Ore Brasil'']], the largest bulk carrier in service
* [[MV Paul R. Tregurtha|''Paul R. Tregurtha'']], the largest bulk carrier on the [[Great Lakes]]
* [[MV Sygna|''Sygna'']]

== Notes ==
{{Reflist}}

== References ==
* {{cite book |author=Autoridad del Canal de Panamá |author-link=Panama Canal Authority |title=MR Notice to Shipping Number N-1-2005. |url=http://www.pancanal.com/eng/maritime/notices/n01-05.pdf |access-date=2008-04-01 |series=Notices to Shipping |year=2005 |publisher=Autoridad del Canal de Panamá |location=Balboa-Ancon |pages=11–12 |archive-date=11 June 2011 |archive-url=https://web.archive.org/web/20110611094533/http://www.pancanal.com/eng/maritime/notices/n01-05.pdf |url-status=dead }}
* {{cite book|last1=Bliault|first1=Charles|last2=Jonas|first2=Martin|last3=The North of England P&I Association|title=Bulk Cargoes: A Guide to Good Practice|date=2016|publisher=The North of England P&I Association|location=UK|isbn=978-0-9574936-3-6|pages=280|edition=First}}
* {{cite book
|last= Frankel
 |first= Ernst G.
|title= Bulk Shipping and Terminal Logistics
 |year= 1985
|publisher=World Bank
|location=Washington, D.C., U.S.
|isbn= 0-8213-0531-X
 }}
* {{cite book |last=George |first=William |title=Stability and Trim for the Ship's Officer |year=2005 |publisher=Cornell Maritime Press |location=Centreville, MD |isbn=978-0-87033-564-8 |url-access=registration |url=https://archive.org/details/stabilitytrimfor0000unse }}
* {{cite book |last=Hayler |first=William B. |title=American Merchant Seaman's Manual |year=2003 |publisher= Cornell Maritime Pr |isbn= 0-87033-549-9 }}
* {{cite web
| url = http://www.imo.org/includes/blastDataOnly.asp/data_id%3D7987/BULK99.FIN.pdf
| title = IMO and the safety of bulk carriers
| access-date = 2007-04-09
| author = International Maritime Organization
| author-link = International Maritime Organization
| date = September 1999
| work = Focus on IMO
| archive-url = https://wayback.archive-it.org/all/20080414073549/http://www.imo.org/includes/blastDataOnly.asp/data_id=7987/BULK99.FIN.pdf
| archive-date = 14 April 2008
| url-status = dead
}}
* {{cite book
|last= Isbester
 |first= Jack
|title= Bulk Carrier Practice
|year= 1993
|publisher=The Nautical Institute
|location=London
|isbn= 1-870077-16-4
 }}
* {{cite book |author=Lamb, Thomas |title=Ship Design and Construction Vol. I |publisher=Society of Naval Architects and Marine Engineers |location=Jersey City |year=2003 |isbn=0-939773-40-6 }}
* {{cite web |author=MAN Diesel Group |title=Propulsion Trends in Bulk Carriers |year=2005 |url=http://www.manbw.com/files/news/filesof5479/5510-0007-00ppr.pdf |access-date=2007-04-12 |page=4 |work=MAN Diesel Group |archive-date=31 October 2008 |archive-url=https://web.archive.org/web/20081031043518/http://www.manbw.com/files/news/filesof5479/5510-0007-00ppr.pdf |url-status=dead }}
* {{cite book|author=International Association of Classification Societies|author-link=International Association of Classification Societies|title=Requirements Concerning Strength of Ships|chapter-url=http://www.iacs.org.uk/document/public/Publications/Unified_requirements/PDF/UR_S_pdf158.PDF|series=Unified Requirements|year=2007|publisher=International Association of Classification Societies|pages=21–1|chapter=21: Evaluation of Scantlings of Hatch Covers and Hatch Coamings of Cargo Holds of Bulk Carriers, Ore Carriers and Combination Carriers (Rev. 4)|archive-url=https://web.archive.org/web/20080530021754/http://www.iacs.org.uk/document/public/Publications/Unified_requirements/PDF/UR_S_pdf158.PDF|archive-date=30 May 2008|url-status=dead}}
* {{cite web
| url = http://www.marad.dot.gov/MARAD_statistics/2005%20STATISTICS/World%20Merchant%20Fleet%202005.pdf
| title = World Merchant Fleet 2001–2005
| access-date = 13 March 2007
| author = Office of Data and Economic Analysis
| date = July 2006
| publisher = United States Maritime Administration
| archive-url = https://web.archive.org/web/20070221134647/http://www.marad.dot.gov/Marad_Statistics/2005%20STATISTICS/World%20Merchant%20Fleet%202005.pdf
| archive-date = 21 February 2007
| url-status = dead
}}
* {{cite book
|last= Thompson
|first= Mark L.
|title= Queen of the Lakes
 |year= 1994
|publisher=Wayne State Univ. Press
|location=Detroit
|isbn= 0-8143-2393-6
 }}
* {{cite book|last1=Nick|first1=Tolerton|title=Bulk Carriers: The Ocean Cinderellas|date=2005|publisher=Willsonscott Publishing|location=Christchurch, NZ|isbn=9780958253567}}
* {{cite book|author=United Nations Council on Trade and Development (UNCTAD)|title=Review of Maritime Transport, 2005|url=http://www.unctad.org/Templates/StartPage.asp?intItemID=2614&lang=1|year=2005|publisher=United Nations|location=New York and Geneva|author-link=United Nations Council on Trade and Development|archive-url=https://web.archive.org/web/20080513201212/http://www.unctad.org/Templates/StartPage.asp?intItemID=2614&lang=1|archive-date=13 May 2008|url-status=dead}}
* {{cite book |author=United Nations Council on Trade and Development (UNCTAD) |title=Review of Maritime Transport, 2006 |url=http://www.unctad.org/en/docs/rmt2006_en.pdf |year=2006 |publisher=United Nations |location=New York and Geneva |author-link=United Nations Council on Trade and Development |access-date=2 May 2008 |archive-date=28 July 2011 |archive-url=https://web.archive.org/web/20110728143716/http://www.unctad.org/en/docs/rmt2006_en.pdf |url-status=dead }}
* {{cite book
|last= Zera
|first= Thomas F.
|title= Ore-Oil Bulk: Pictorial History of Bulk Shipping Losses of the 1980s
 |year= 1996
|publisher=Rutledge Books
|location=Bethel, CT
|isbn= 0-9643937-7-8
}}

== External links ==
{{Commons}}
* [https://web.archive.org/web/20050120091302/http://www.oceansatlas.com/unatlas/uses/transportation_telecomm/maritime_trans/shipworld/cargo_car/bulk/bulk_carriers.htm Bulk Carriers @ United Nations Atlas of the Oceans]
* [http://www.marin.nl/web/show/id=77616 Bulk Carriers at MRI Netherlands] {{Webarchive|url=https://web.archive.org/web/20090530044012/http://www.marin.nl/web/show/id=77616 |date=30 May 2009 }}
* [http://www.t2tanker.org/ships/nashbulk.html Histories of WWII bulk carriers]
{{clear}}

{{ModernMerchantShipTypes}}
{{Authority control}}

{{DEFAULTSORT:Bulk Carrier}}
[[Category:Bulk carriers| ]]
[[Category:Ship types]]
[[Category:1852 introductions]]