Vessels up to 24 metres Load Line Length, excluding Fishing Vessels, may be measured by Y.D.S.A. and I.I.M.S. Measurers for tonnage using the “Simplified” method by measuring overall length, breadth and depth. Below is the Measurement Procedure for vessels under 24 metres overall length.

Metric measurements are now used to the nearest 1/100 metre (centimetres) rather than the 1/10 foot. The Tonnage calculations are used as follows using outlined definitions. Briefly the calculation is as follows:

Length overall x Breath x Depth x 0,16

(Please contact our offices for more explicit details)

If the length overall is over 24 metres she can still be measured but the measurer must also ensure that the vessel is under both 24 metres Load Line Length and Registered Length as defined below. It may be helpful to consult the drawings of the vessel when determining Load Line and registered length. Great Care is needed to ensure she really is under 24 metres Load Line Length.

LOAD LINE LENGTH is defined as the greater of the following distances: The distance between the fore part of the stem to the aft and the axis of the rudder stock OR 96% of the distance between the fore side of the stem and the aft of the stern. The points and measurements being taken respectively at and along a waterline at 85% of the least moulded depth of the ship. In the case of a ship having a rake of keel the waterline shall be parallel to the designed waterline.

REGISTERED LENGTH is the length from the fore part of the stem to the aft side of the stern post (or in a ship not having a stern post) to the fore side of the rudder stock at the point where the rudder stock passes out of the hull. In ships not having a stern post or rudder stock the after terminal point is taken to the outer face of the transom or stem of the ship. With regard to the forward terminal the measurement is to be taken to the forward face of the structure above the deepest load waterline which is an integral part of the ship, being connected by welding or riveting but not bolts, and do not include bulbous or ram bows

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Explanation of Load Line Length

LOAD LINE LENGTH is an IMO (International Maritime Organisation) term and was an attempt to ignore funny shaped ships being built to cheat length. What they are defining is a length at 85% of the height of the hull above the top of the keel measured parallel to the waterline and thus ignoring the upper sections of flared bows, counter stems etc.

REGISTERED LENGTH is the old way of measuring length and is often still quoted in the U.K. again it may be helpful to consult the drawings of the vessel if determining load line and registered lengths.

All this may seem daunting but we can supply documentation on request which explains in depth the various points of measurement used and all relevant terms involved.

All the forms which you will require for requesting an “APPLICATION for TONNAGE MEASUREMENT” and Application for MCA Coding through the Certifying Authority form reference “SCV1” may be emailed or posted on request.

Please feel free to contact us for a quote and to discuss your particular requirements.

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Marine Surveyors
Loft 1
La Soufflerie
15, rue du Lac
06400 Cannes
Tel: + 33 (0)609 524 166
Fax: + 33 (0)493 996 016 Yacht Designers and Surveyors Association International Institute of Marine Surveying