Bunker is the name given to the fuel (oil) used in ships. There are different types of ‘bunker’ and within those types there are also different standards grades and classifications. For example: MDO (marine diesel oil) MGO (marine gas oil) MFO (marine fuel oil) HFO (heavy fuel oil) and IFO (intermediate fuel oil). Bunker can also refer to the tank or compartment that the fuel is stored in.

Bulk Cargo is goods that are brought onboard the vessel in loose form and unpacked. For example coal coke fertilizers grain iron ore cement phosphate and minerals - basically anything that can be pumped or poured. The cargo is loaded directly into the ship’s holds. Ships that carry Bulk Cargo are known as bulk carriers or bulkers.

Also called Beam the Breadth is the width of a vessel.

A Bight is a loop or bend in a rope.

The Bridge Deck is the deck upon which a vessel's navigational equipment is housed.

A Bulk Container is a shipping container that has been specifically designed for carrying free-flowing dry cargo such as grain coal or cement. The cargo is poured into the container via openings in its roof and later discharged through other openings at the end of the container.

The Bulwark on a ship is a fore-and-aft vertical plating found directly above the upper edge of the vessel’s side surrounding the exposed deck or decks.

Bagged Cargo is any type of cargo that is normally packed in bags or sacks - such as cement grain flour sugar powdered milk etc.

Also called Breadth the Beam is the width of a vessel.

A Ballast Tank is a watertight compartment that is used for holding ballast water.

A Bunk is a bed (or berth) in crew accommodation that is usually built into the cabin.

A Boiler is a unit that generates steam to propel a ship. Boilers are also used for onboard heating as well as other auxiliary purposes. 

Ballasting is the process in which seawater ballast is pumped into ballast tanks to achieve a vessel’s desired stability trim and draught.

The Bridge on a ship is a room or platform at the top of a vessel’s superstructure that operates as the command center. All communications and information goes through the Bridge and it will be manned by an Officer of the Watch when the ship is underway. It has a clear view on all sides of the ocean and surrounding area. 

A Bill of Lading (BL B/L or BoL) is a legal document that is issued by or on behalf of a carrier detailing the type and quantity of goods being shipped the shipper the consignee the ports of loading and discharge and the carrying vessel. It also acts as a receipt when the goods are delivered to their destination.

The Blind Sector is an area that cannot be scanned by a ship’s radar because the radar echoes are blocked by obstructions near the antenna such as parts of the superstructure or the masts etc.

The Boundary Layer is a narrow layer of moving water that is adjacent to a vessel’s hull as it travels through water.

Break Bulk Cargo is loose cargo that is carried in drums on pallets in bags or in cartons etc. Break Bulk or Breakbulk Cargo is stowed directly in the vessel’s hold unlike bulk containerized or ro-ro cargo. It is carried by break bulk vessels general cargo vessels or multi-purpose vessels.

Battens or Cargo Battens are inserted into the hold of a cargo ship to keep cargo away from the vessel's sides in order to allow ventilation. 

Also known as a Buoy Tender Vessel or Buoy Laying Vessel a Buoy Layer is a boat that is used for handling maintaining and replacing navigational buoys and beacons. Buoy Tender can also be used to refer to someone who does this for a living.

On a sailboat a Boom is a long spar (a pole) which runs along the foot of a fore and aft rigged sail. The Boom’s main purpose is to make it easier to control the shape and angle of the sail and to ensure the foot is flatter when the sail angle is away from the centerline of the boat. The Boom is tethered by a wire rope or tackle from aloft to its upper end while its lower end is usually hinged and connected to the mast. 

The Boatswain (often called the Bosun) is the highest unlicensed rating in the deck department. They are in direct charge of all deckhands and take their direct orders from the Chief Officer or Master. The Boatswain’s duties involve looking after the hull and deck of the vessel making sure these parts of the ship as well as her anchors windlasses and other such equipment are well maintained and in good working order.

A Boatswain is also responsible for areas such as the Bosun’s store room the paint locker and the deck stores where the tools of their trade such as maintenance equipment tools and supplies are kept.  

BBB stands for Before Breaking Bulk. It is an expression that means making freight payment before a shipment of goods is discharged. Under typical circumstances freight is paid once the goods have been delivered however in the event of BBB freight must be paid before the vessel is allowed to leave port.

Bonded Goods are products which must have duty paid on them which has not yet been paid. For example goods that are in transit or in a warehouse waiting for clearance by customs.

Boottop or Bootopping (used by the merchant navy) is a thin strip of paint which runs around a vessel’s hull. Its purpose is to divide the anti-fouling paint which is below the waterline and the paint used on the topsides. It is usually a contrasting color to the two sections it is dividing. 

The Bosun Store is a small space in which tools and small hardware items are kept so that the Bosun and his or her deckhands can efficiently carry out day to day repairs and maintenance.

Also known as a Buoy Layer or Buoy Laying Vessel a Buoy Tender Vessel is a boat that is used for handling maintaining and replacing navigational buoys and beacons. Buoy Tender can also be used to refer to someone who does this for a living.

Ballast Pumps are electrically-powered and used to pump water in and out of the ballast tanks when cargo is being loaded or unloaded.

A ship’s Bilge is the lowest inner part or the bottom part of the hull that would rest on the ground if the vessel was not supported by water. It encompasses the lower parts of the holds and machinery spaces and is designed to collect excess water.

Ballast Keel is a quantity of ballast which is secured by bolts to the keel to increase a boat’s stability.

Bunkering or to bunker is the act of supplying a vessel with bunker - i.e. with filling its fuel tanks with fuel.

A Bilge Keel is a passive stability system that is used to reduce a vessel's tendency to roll. Bilge Keels are used in pairs one for the port side and one for starboard. On rare occasions a ship may have more than one Bilge Keel per side.

Ballast is any solid or liquid weight that is brought on board a vessel in order to increase stability. For example if the cargo in one hold is heavy and the cargo in another hold is lighter ballast will be used to balance out the weight discrepancy. Ballast is also used if there are rough seas ahead or when the ship is empty of cargo. 

An audible signal that is made with a ship’s whistle. A short Blast is about one second long while a prolonged Blast lasts for between four and six seconds.

1. Berth is a place assigned to a vessel when she is at anchor or is lying alongside a dock or pier etc.
2. A Berth is also a bunk or bed on a ship.
   

A Backhaul is when a vessel returns from her original destination to the original point of departure. 

Bow Thrusters are propellers on the bow which are used as maneuvering aids for the vessel. They are located underwater and turn at right angles to the fore-and-aft line. They push the bow sideways in whichever direction they are employed.

A Break Bulk Vessel is a multi-purpose cargo ship designed for the transportation of break bulk cargo - i.e. cargo that is stowed in the vessel's hold in bags cartons or on pallets

A Barge Aboard Catamaran (BACAT) vessel transports barges which are loaded on and unloaded off whilst it is floating. This is done by partially submerging the BACAT and loading the barges on via a gate in the BACAT's stern.

Also known as Sea Marks Seamarks and Navigation Marks a Beacon is an aid that is fixed to the shore (i.e. a lighthouse) or to the seabed to help navigators and pilots identify the approximate position of a maritime channel or hazard to allow them safe passage of their vessel.

A Ballast System consists of ballast pumps and piping and enables water to be drawn from the sea or from a ballast tank and then discharged to another ballast tank or the sea. 

The Bale Capacity is the total amount of space available for the carriage of bales bags pallets or boxed cargo excluding the space between the frames and beams. The Bale Capacity is always slightly less than the Grain Capacity. 

The ship's Bell is used to announce the time as an alarm in the event of an emergency and its most common use these days as a safety signal when the vessel is in foggy conditions. A Bell usually has the ship’s name engraved on it and is most often made from bronze or brass. 

Boarding Arrangements or Boarding Facilities refer to the gear required for a pilot (and other personnel) to board a vessel such as pilot and accommodation ladders gangways and ramps mechanical hoists and shell doors. 

Boarding Speed is the speed of a vessel when it is adjusted to that of a pilot boat so that the pilot can safely embark.

Bilge Blocks are used to support the bilge while the vessel is under construction or in dry-dock.

BIMCO is the Baltic and International Maritime Council a commercial shipping trade organization and the largest international direct-membership organization for shipowners shipbrokers charterers and agents in the world.

The name given to water that collects in a vessel’s bilge. Bilge Water is pumped out due its tendency to become foul smelling and putrid. Bilge Water also contains other fluids such as those from internal drainage systems machinery sludge tanks and other sources. 

Berthing is the act of approaching a port or harbor and securing the vessel in its assigned place - i.e. its berth.

The Bow is the forward part of the hull of a ship or boat. Under normal circumstances the Bow will be pointing forward when the vessel is underway. 

A Buoy is a Seamark (or Sea Mark) - a floating object that is used as a navigational aid to help sailors identify the navigable limits of channels their fairways and sunken dangers such as rocks or shallow ground etc. They can also be used as a reference point for navigation or other reasons.

Box is a slang word for shipping container.

Broken Stowage is the term given to ‘lost’ cargo space in a vessel’s holds due to a mismatch in the shape of the hull and the shape of the cargo. 

The Bulkhead Deck is the uppermost continuous deck of a ship to which all main transverse watertight bulkheads are carried.

A Bunkering Vessel is a small tanker that is used to load fuel oils (bunker) into a ship’s tanks. It is equipped with fuel pumps and a crane for hose handling for this purpose.

Boarding Facilities or Boarding Arrangements refer to the gear required for a pilot (and other personnel) to board a vessel such as pilot and accommodation ladders gangways and ramps mechanical hoists and shell doors. 

A Bonded Warehouse is a storage facility where bonded goods (goods that are waiting for the duty to be paid on them) are stored. 

A Bareboat Charter (also called a Demise Charter) is an agreement in which a vessel is chartered - or hired - without crew or provisions. The renter of the boat or ship takes care of these things themselves.

BDN stands for Bunker Delivery Note -  a document which contains information pertaining to the delivery of fuel to a ship. This includes the vessel’s name the port the bunkering took place at the date the amount and type of fuel and the supplier’s information.

Boat Falls are the tackle used to lower or hoist a ship’s boat or lifeboat to or from the davits.

A Barge is a flat-bottomed boat which is used to transport bulky freight such as sand coal stone or lumber etc. by canal or river.

A Bell Buoy is a buoy that is fitted with a bell that sounds as the buoy moves with the motion of the sea.

The Blue Peter is a blue signal flag with a white square in the center. It is hoisted to indicate that a merchant ship is ready to sail.

BoL stands for Bill of Lading (also known as BL or B/L.) It is a legal document that is issued by or on behalf of a carrier detailing the type and quantity of goods being shipped the shipper the consignee the ports of loading and discharge and the carrying vessel. It also acts as a receipt when the goods are delivered to their destination.

A Backstay is a long line or cable that runs from the rear of the vessel to the mast heads. Backstays help to support the mast.

Barge Carriers are ships that are designed to carry barges. The barge is loaded onto the carrier either by floating it on to the partially submerged carrier through a gate in the stern or by lifting it over the stern using a gantry crane. 

A Bay is a space on a cargo ship that is meant for holding containers. A container ship will have several Bays all of which are either under-deck (the hold) or on-deck. A numbering system enables ordered loading and unloading with even numbered Bays being suitable for 40-feet containers and odd numbered Bays being for 20-foot containers.

If a cargo ship needs to sail without cargo or with only a small quantity of cargo it needs to travel in ballast. Generally this means carrying sea water in the ballast tanks to keep the vessel in trim and to ensure that the propeller and rudder are submerged. A Ballast Movement is the voyage or leg of a voyage spent under these conditions.

Before Breaking Bulk is an expression that means making freight payment before a shipment of goods is discharged. Under typical circumstances freight is paid once the goods have been delivered however in the event of Before Breaking Bulk (BBB) freight must be paid before the vessel is allowed to leave port.

A Bilge Pump is a water pump that is used to drain bilge water from a vessel. Many electric Bilge Pumps are fitted with float switches which activate the pump when the bilge fills to a specified water level 

BL stands for Bill of Lading (also known as BoL or B/L.) It is a legal document that is issued by or on behalf of a carrier detailing the type and quantity of goods being shipped the shipper the consignee the ports of loading and discharge and the carrying vessel. It also acts as a receipt when the goods are delivered to their destination.

A Back-up Navigator is not an actual job but the name given to a member of the crew (usually an Officer) who has been assigned by the Master to be on call in the event that assistance is needed on the bridge.

BACAT stands for Barge Aboard Catamaran. This is a vessel that transports barges which are loaded on and unloaded off whilst it is floating. This is done by partially submerging the BACAT and loading the barges on via a gate in the BACAT's stern.

The Bunker Delivery Note (BDN) is a document which contains information pertaining to the delivery of fuel to a ship. This includes the vessel’s name the port the bunkering took place at the date the amount and type of fuel and the supplier’s information.

The Boss Hub or Propeller Hub is the central portion of a screw propeller to which the blades are attached and through which the propeller shaft end passes.

A Bollard is found both on ships and on wharfs/docks. Generally speaking they are metal bases that are welded to the deck of a vessel or fastened to the dock with two vertical bitts that are welded onto the sides to create a secure fastening for the mooring and berthing lines.

Also known as a Buoy Tender Vessel or Buoy Layer a Buoy Laying Vessel is a boat that is used for handling maintaining and replacing navigational buoys and beacons. Buoy Tender can also be used to refer to someone who does this for a living.

The Bosun (also sometimes called the Boatswain) is the highest unlicensed rating in the deck department. They are in direct charge of all deckhands and take their direct orders from the Chief Officer or Master. The Bosun’s duties involve looking after the hull and deck of the vessel making sure these parts of the ship as well as her anchors windlasses and other such equipment are well maintained and in good working order.

A Bosun is also responsible for areas such as the Bosun’s store room the paint locker and the deck stores where the tools of their trade such as maintenance equipment tools and supplies are kept.

A Bulkhead is an upright partition or wall in a ship’s hull which subdivides the vessel’s interior into watertight compartments. In the event of an accident they reduce the extent to which the seawater can flood the ship whilst also adding extra strength to the hull girder.

On some flying bridges there will be Bridge Wings which are narrow walkways / open areas that expand outwards over the sides of the vessel. These allow an Officer to see the side of the ship while docking undocking and working with smaller vessels such as when picking up or dropping off the pilot.

A Bulk Carrier also called a Bulker is a vessel that has been designed to carry loose cargo that is directly loaded into the vessel with no packaging. Cargo can include coke coal grain cement iron ore minerals or fertilizers.