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.
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.
Bar draught. This expression relates to the maximum draught enabling the ship to pass over a "bar", for example the Martin-Garcia bar in the River Plate. A "bar" is a restriction in the depth of water, caused by a build-up of sand or silt on the bottom, in a river or across the entrance to a harbour.
Brokerage (or Commission). It is customary to express the remuneration for the broker's time and efforts in negotiating and arranging the contract as a certain percentage of the money earned by the shipowner. (In marine insurance, the broker is generally paid a commission by the underwriter although the assured is the broker's client and the services are for the client.) In shipbroking, the term "brokerage" is generally preferable instead of "commission" because the latter term is usually related to the charterer's reward as "address commission".
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.
Breakdown clause. Time charterparties contain a clause providing that if the ship is unavailable for the charterer's use because there is loss of time as a result of "...breakdown or damages to hull, machinery or equipment..." (among other causes) payment of the hire money to the shipowner ceases for all or some of the time lost.