Tonnage Survey

A tonnage survey measures and certifies the gross and net tonnage required for official registration. It is a mandatory step for Part I registration on the British flag and is carried out within the MCA framework.

What a tonnage survey is

Gross tonnage is a standardised calculation of a vessel’s enclosed volume — not its weight. For registration under the UK flag (UK Ship Register, Part I) this figure must be measured and certified to MCA standards. The same figure feeds port dues, insurance classification and several fee schedules.

How it is measured

Length, breadth and depth are taken together with the enclosed spaces — accommodation, engine room, stores — using the prescribed method, with the vessel afloat; no haul-out is needed. The calculated gross tonnage is reported in the MCA-recognised format and the tonnage certificate issued.

Why it is measured on board

Tonnage is not the length in the builder’s brochure; it is the measured volume of the boat. Later additions — an enclosed flybridge, a bathing platform, a hardtop — change the tonnage, and the figure in the registration file no longer describes the boat.

The measurement is taken on board with a laser distance meter and a digital level; length, breadth, depth and enclosed volumes are recorded. The calculation follows MCA rules and the result goes straight into the registration file.

Part of the registration package

The tonnage certificate is a precondition of flag registration, and we run it as one step of the complete UK Flag Registration package — measurement, company formation, MMSI and registry paperwork handled together. For vessels over 24 metres (Load Line length) the survey is more extensive; we clarify the scope in the first conversation.

Duration and fee

The measurement takes 1 working day; the paperwork runs afterwards.

Fees vary with the length of the boat, where she lies and the season. For a firm price call us — tell us about the boat and we will give you the number on the phone.

Estimate your survey fee