This is a collection of terms that I have built up after being asked by someone what something means or which I have heard people appear to misunderstand. I have endeavoured to explain each in simple terms.
Click here for my list of industry acronyms.
Actual Total Loss - A reference to a vessel which has been completely destroyed or irretrievably lost. For example where a boat is broken to pieces in a storm and scattered by the sea or where a ship sinks in very deep water. Can be contrasted with Constructive Total Loss (below).
Air Draught - Refers to the space available above water, for instance to warn of low handing objects of cranes.
Anchorage - An area where vessels can safely drop anchor and stay, usually close to a port.
Bunkers - The fuel used on ships, i.e. people will often say the ship is going into port to 'take on bunkers'. The term can actually apply to any form of fuel oil which is used onbaord a ship, it doesn't have to be used in the ship's main engine. Therefore even diesel oil used by equipment onboard can be said to be 'bunkers'. Lub oil would not however be classed as bunkers because it is not fuel.
Butterfly Valve - This is a type of valve used in pipes or pipelines which allows the pipe to be closed or flow through it limited, from the outside. This is done by turning a handle or moving an actuator (often controlled by a motor) on the outside of the pipe which turns a circular piece inside the pipe which can close off the pipe. When turned completely sideways the pipe is fully open. A picture of the pipe design is available here. Because defects in the valve are only usually noticeable after a failure occurs (the working mechanism is invisible from the outside) this can lead to incidents onboard.
Butterworthing - This describes the system of cleaning the tanks onboard a vessel with a special hose with multiple nozzles, like this, which spray high pressure water in all directions. The system was used by, and hoses produced by, a company called Butterworth, which resulted in the type of tank cleaning being described as Butterworthing (much like how 'vacuum cleaning' became 'hoovering').
Common Carrier - Most 'carriers' for the purpose of shipping law are contractual carriers, in other words they carry cargo or people against a Bill of Lading or passenger ticket, i.e. on agreed terms. There do still exist what are known as 'common carriers' who basically agree to move certain goods or people based only on common law terms. They generally issue no documents with terms on them and carry lots of small amounts of goods or people on short journeys and wish to keep admin' costs low. The equivalent on land would be a public bus, where someone can jump on and off without agreeing any carriage terms.
Constructive Total Loss (CTL) - This is a reference to a vessel which is being treated as a total loss for insurance purposes even though it is physically still there. This generally applies where the cost of salvaging the vessel or making it usable again is greater than the value of the vessel itself (i.e. greater than the cost of buying another similar vessel). For example where a ship worth USD 50,000 is grounded and a hole is punctured in its hull, the quoted cost of patching the hull, towing it to port and fully repairing it might be USD 75,000. In the circumstances its owners would call their hull insurers and tell them they were treating it as a CTL.
Ice Demurrage - This is a type of Demurrage which uniquely occurrs when a port that a charterer has asked a ship to go to is closed or blocked due to ice. Generally the ship will be able to claim demurrage for the resultant delays at the standard demurrage rate as it is a risk of the charterer, trading in such areas, that the ports will be closed and it is generally considered that the price of the goods involved will 'factor in' such risks and costs.