Blockade. Belligerent powers have the right of blockade, i.e., the right to blockade enemy ports or coastal territory for ocean shipping by military measures.

The blockade must be respected by neutral states. Running a blockade, if unsuccessful, may entail boarding and searching for contraband and confiscation of ship and cargo.


Builder’s certificate. As the name indicates, this certificate is issued by the shipbuilding yard, containing a true account of the estimated tonnage; the year and place where the vessel was built and also the name of the owners and other details. This certificate is required in addition to the declaration of ownership , on the first registry of the ship.


BARECON "B". A financial-type of standard-form bareboat charterparty used particularly for new building ships financed by mortgage.


Butterworth tank cleaning system. This is a method for cleaning and gas freeing oil tanks by means of high pressure jets of water, either cold or heated. The apparatus consists essentially of double opposed nozzles which rotate slowly about their horizontal and vertical axes, projecting two high pressure streams of water against all inside surfaces of the deck, bulkheads, tank framing and shell plating.


Barrel (Bbl). A unit of measurement of liquid cargoes, usually oil. One bbl contains 34.97261 Imperial gallons or 42 U.S. gallons, or 1 cubic metre of oil measures 6.29 bbls. If the specific gravity of the oil is 0.8, one tonne of oil will be approximately 7.9 bbls


Below bridges (BB). This term can be Found in instructions from port and charterers' agents to the ship to ensure that the ship is kept at the appropriate draft in order to ensure that it will have sufficient clearance above its highest point to pass safely below bridges (or overhead obstructions such as power cables) across a canal, channel or river in the approaches to a berth or port. To ensure the ship's clearance below bridges would be the shipowner's obligation.


Bilge. The bilge of a vessel with double bottom tanks is a triangular channel on both sides formed by the margin plate of a double bottom, the curvature of the outer skin of the vessel and the bilge ceiling.

Black list. Because oil tankers frequently load oil from Islamic countries these countries may place certain ports on a "black list" such as Israeli or South African ports, and if tankers are known to have called at ports in those countries, the tankers' names are on this black list and the ship can be boycotted and refused entry or cargo.

Boycott clause. A charterer may insist that a charterparty contains a clause, which causes the shipowner to take the risks if the vessel is delayed by a "boycott" by labour.

Ballast. In order to increase the stability of ships, which have to be dispatched without cargo and to ensure that the propeller will be immersed sufficiently, say about two-thirds of its diameter, a sufficient quantity of ballast will be loaded before sailing. The quantity of ballast depends on the type of vessel, quantity of water which can be taken in the ballast tanks and also the voyage to be made. Seasonal weather conditions which may be expected on the voyage must also be considered.


Beaufort Wind Scale. At sea the wind speed is expressed in numbers according to the Beaufort scale. The Beaufort Number (BF) is estimated from the sea surface appearance.

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