YACHT & POWERCRAFT DESIGN SERVICES

If there are no plans available, it is often necessary to “take-off” the lines of a yacht or small craft to produce drawings for subsequent technical work.  The lines plan produced in this way may be needed for stability calculations prior to certification, or to enable modifications to be planned for the interior spaces or accommodation.  Some owners like to have the plans of their boat available for reference, or to enable them to construct a half model for display at home.  If the boat is successful, but getting rather old, it is also very valuable to have a copy of the lines of the original boat before going on to discuss the design of a completely new replacement vessel with a yacht and boat designer.

I have taken the lines off a number of vessels using traditional graduated rods, plumb bobs and spirit levels as well as with purpose-built equipment such as chain girth devices or laser distance devices.  When I have taken a set of measurements for both the profile offsets and the transverse sections, they become the input data to a computer program which enables a surface to be fitted through the points and a lines plan developed and faired.  Depending on the number of helpers it normally takes about a day to lift off the measurements and a further day to create and fair the lines plan.  

The most accurate results are obtained when the boat is set up level on a flat concrete base, preferably in a workshop.

Working on an inclined slipway between tides, as shown on the left, is far from ideal!   

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Usually it is harder to do on motor boats.

Then laying off the measurements onto a lofting board.

Taking  Off  Hull  Lines  

Taking off the section shape with a chain girth device.

Yacht & Powercraft Design Services Ltd
 Email:  info@yacht-designer.co.uk
Tel. 44 (0) 1489-583346   Fax. 44 (0) 1489-583346  Mobile  07803-724317