Tonnage Measurement · UK
Tonnage Measurement UK
Gross and net tonnage calculated to the UK Merchant Shipping (Tonnage) Regulations for UK Part 1 and Red Ensign Group registered yachts — authorised Tonnage Measurer attending across the UK.
What this service involves
Tonnage measurement is a statutory volumetric calculation of a vessel's enclosed spaces, used as the basis for vessel registration, port and canal dues, and certain certification regimes. It is not a weight — it is a measure of internal volume, expressed as Gross Tonnage (GT) and Net Tonnage (NT), and it must be carried out by a Tonnage Measurer authorised by the flag-state administration.
SVG Marine is an authorised Tonnage Measurer working for owners, brokers, registry agents and flag administrations across the UK. We measure to the UK Merchant Shipping (Tonnage) Regulations, and our certificates are accepted by the UK Ship Register and by Red Ensign Group registries including Cayman, BVI, Isle of Man, Gibraltar and Jersey / Guernsey.
The typical engagement is straightforward: we attend the vessel, measure the enclosed spaces and exempted volumes, calculate gross and net tonnage to the regulations, and issue the documentation needed by the registry agent to complete the vessel's registration. For new builds we can work from compliant general-arrangement and capacity drawings where the flag administration accepts a drawings-based calculation.
Tonnage measurement is also required following refits or structural changes that alter enclosed volumes — typical examples are new fly-bridge enclosures, transom extensions or saloon expansions on motor yachts, and below-decks volume changes on sailing yachts.
Where we work
We attend tonnage measurement appointments throughout the UK — Southampton and the Solent regularly, South Wales as standard, the South West, East Coast and Scotland on request. Most measurements are arranged within two to three weeks of first enquiry.
- Southampton
- Hamble
- Cowes
- Lymington
- Portsmouth
- Chichester
- Poole
- Dartmouth
- Plymouth
- Falmouth
- Cardiff
- Swansea
- Bristol
- East Coast
- Glasgow / West Coast Scotland
Recent projects
A selection of recent assignments — vessel and client details anonymised where required by our duty of confidentiality to owners, insurers and buyers.
55ft motor yacht — Southampton
Tonnage measurement for UK Part 1 registration following ownership change and lender requirements. Certificate issued within ten days.
45ft sailing yacht — Hamble
Re-measurement after a stern-extension refit altered enclosed volumes. Documentation updated with the UK Ship Register.
78ft motor yacht — Cardiff
Cayman Islands tonnage measurement on a yacht relocating its registration; coordinated with Cayman registry agent.
38ft sailing yacht — Plymouth
First-time Part 1 registration measurement for an owner-completed build. Drawings reviewed and on-board verification completed.
62ft motor yacht — Cowes
Tonnage measurement combined with MCA coding examination — single mobilisation covering both work streams.
42ft catamaran — Falmouth
Multihull tonnage measurement for UK Part 1 registration; calculation accounting for the multihull enclosed-spaces geometry.
Frequently asked questions
What is yacht tonnage measurement?
Tonnage measurement is the formal calculation of a vessel's gross and net tonnage under the UK Merchant Shipping (Tonnage) Regulations, used for vessel registration, certification and statutory documentation. Tonnage is a volumetric measure of the vessel's enclosed spaces — not a weight.
When do I need a tonnage measurement?
Tonnage measurement is required when registering a vessel on the UK Part 1 register or a Red Ensign Group register (Cayman, BVI, Isle of Man, Gibraltar, etc.), when refitting work changes the enclosed volume, when changing flag, and in some cases for commercial certification.
Who is authorised to carry out tonnage measurement?
Tonnage measurement must be carried out by a Tonnage Measurer authorised by the flag-state administration. SVG Marine holds Tonnage Measurer authorisation and is engaged directly by owners, brokers and registry agents for UK and Red Ensign tonnage work.
What size of vessel needs tonnage measurement?
Any vessel intended for UK Part 1 or Red Ensign registration above the relevant threshold — in practice, most yachts being registered on Part 1 for full title registration require measurement.
How long does the measurement take?
On-board measurement typically takes half a day to a full day depending on size and complexity. The tonnage certificate documentation is normally issued within one to two weeks.
Can the measurement be done from drawings?
In some cases tonnage can be calculated from compliant general-arrangement and capacity drawings — particularly for new builds. For existing vessels, an on-board measurement is normal and often required by the flag administration.
Where do you carry out tonnage measurement in the UK?
Throughout the UK — Southampton, the Solent, the South Coast, South Wales, the South West, East Coast and Scotland on request. Most measurements are arranged within two to three weeks of first enquiry.
Do you also handle Red Ensign tonnage?
Yes. UK Part 1, Cayman, BVI, Isle of Man, Gibraltar, Bermuda and Jersey/Guernsey tonnage requirements are routinely handled, in coordination with the appointed registry agent.
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