PMA: Ships: Outline and meaning of ship
Ships are treated more generously than other assets by the capital allowance system. A ship owner can claim a WDA (or an FYA if available) and then postpone it CA25200. This means that the allowance need not be taken in the chargeable period for which it is claimed but can be taken in a later chargeable period provided that the qualifying activity is still being carried on. Shipowners can also defer balancing charges arising in respect of ships by setting them off against expenditure on new shipping CA25300.
There is no definition of ship in CAA01 so you should give ship its ordinary meaning.Treat any vessel registered by the Maritime Coastguard Agency as a ship as a ship for capital allowance purposes. The Merchant Shipping Act 1995 defines a ship as including every description of vessel used in navigation. Accept that anything that is covered by the Merchant Shipping Act 1995 definition of ship is a ship for capital allowance purposes. This means that you should treat any vessel that is capable of being manoeuvred under direct or indirect power as a ship.
Oilrigs and platforms, accommodation barges, light and weather ships etc are not generally regarded as ships. They do not normally move about and are not used in navigation. Semi-submersible oilrigs and similar vessels in the oil and gas industry may be ships, depending on the use made of them. This use-based approach was followed by the Court of Appeal in Clark v Perks (2001) [which held that a semi-submersible drilling rig could beconsidered as a ship]. As a result, you should not automatically accept that all such vessels qualify as ships.