As part of a two-part series for Water Craft magazine investigating different methods for lifting lines from boats, I designed a slotted spiling board and a girth chain to use when measuring the inside or outside hull shape of boats.
The spiling board is designed to be used with a method we call the ‘Pointer Technique’, which uses a series of adjustable pointers to directly transfer inside hull shapes to paper. It works well with open, undecked boats which can be measured upright and is particularly suitable for use with clinker hulls.
A girth chain is an adjustable template tool with articulated links, designed to lift a shape directly from a hull onto a scrive board or straight to timber for building.
Although traditionally used in boatbuilding, girth chains are no longer widely available.
I had both designs cut out for me in 12mm (½”) plywood by CNC router at Fibrefusion in Falmouth. The components for the two designs are nested to 1220mm x 1800mm (48” x 71”), in order to fit a single sheet of standard sized plywood and are both joined together using 45mm (1¾”) long M6 (¼”) cup square bolts, wing nuts and penny washers.
These designs were featured in Water Craft magazine (No.117 May/June 2016 and No.118 July/August 2016) and are available as a free half-scale PDF download below: