There shall be exempted from dues under this Schedule:–
Ships belonging to Her Majesty or to a foreign Government unless carrying cargo or passengers for freight or fares;
Sailing ships (not being pleasure yachts) of less than 100 tons, and all ships (not being fishing vessels) of less than 20 tons;
Ships (other than tugs or pleasure yachts) when navigated wholly and bona fide in ballast, on which no freight is earned and without any passenger;
Ships putting for bunkers, stores, or provisions for their own use on board;
Fishing vessels of less than 10 metres in length;
Ships putting in from stress of weather or for the purpose of repairing, or because of damage, provided they do not discharge or load cargo other than cargo discharged with a view to such repairs, and afterwards reshipped;
Dredgers and hoppers for the time being employed solely in dredging channels or deepening water for or on behalf of a harbour authority or a conservancy authority, within the area in which that authority has jurisdiction, or in disposing within or without such area, otherwise than by way of sale or exchange, of the spoil from such operations;
Sailing yachts of and above 100 tons, which are not registered in the United Kingdom, Isle of Man, Channel Islands or the Republic of Ireland, and which come into the territorial waters of the United Kingdom or the Republic of Ireland with the sole object of taking part in yacht racing, so long as such yachts are coming into, remaining in, or leaving such territorial waters solely in connection with such object, and hold a certificate in a form approved by the Secretary of State;
Ships making voyages entirely performed in waters in respect of which no lighthouse, buoy or beacon is maintained by a general lighthouse authority at the expense of the General Lighthouse Fund;
Yachts in respect of any year ending 31st March during the whole of which they are laid up, and fishing vessels in respect of the ten month period ending 31st March 1990 during the whole of which they are laid up; and in the case of a fishing vessel which has opted to pay in two payments are provided for in Rule 10, this exemption shall apply in respect of any period covered by such option, during the whole of which it is laid up.