Fish Template

TECHNICAL LIBRARY

HANDY HINTS

THE FISH TEMPLATE AND ITS USE

A Fish Template is a very handy pattern shape used for transferring a complex shape from an original mould to a plane surface. The Fish Template shown below is at 50% size. However using either a graphics program or a photocopier it can be either scaled up or down to suit the particular job. To make a fish template save the image shown, adjust the image size as required in a graphics program before printing a copy. Make another copy with a photocopier to adjust the size if required. With the required size on paper cut out around the border, paste or trace the template on to a solid backing - cardboard, ply or aluminium sheet and cut the backing to match the template. Carefully smooth the edges to preserve the shape.

A TYPICAL JOB FOR A FISH TEMPLATE

An extra bulkhead is required for the forward section of a boat where the shape is complex and the placement is in a difficult area. If a bulkhead is needed to fit the shape shown it could take days to prepare the ply or metal to fit accurately enough. The steps below show a simple and accurate method to make a shaped bulkhead. It is advisable to read all the steps to get a good overview before work begins.

STEP 1.
Cut a piece of wood rigid enough to span the job without bending and temporarily attach it so that it cannot move during the following tracing steps. Cut out a piece of fairly rigid cardboard or thin ply to cover most of the proposed bulkhead area. Fix this firmly to the piece of timber - as shown. Call this the Transfer Sheet (TS)

STEP 2
Position the Fish Template (FT) so that the point is just touching the inner surface and, holding it steady against the TS, draw a line around the FT on the TS. The pencil used to draw this line must be sharp enough to allow the FT to be later positioned exactly in the same place on the TS. Reposition the FT repeating this process until there are enough FT traces to complete the transfer process shown in Step 3. More traces will be needed to be made at tight corners. Accuracy gets better as the number of traces increases.

STEP 3
Mark both the wood holding the Transfer Sheet and the boat / mould so that the TS can be repositioned in precisely the same place if later required to get more traces. Carefully remove the wood and TS, place and temporarily fix on the material that is to become the bulkhead. Reposition the FT exactly on all the traces taken and put a mark on the new bulkhead where the point of the FT is located. Then join up all the marks to produce the cutting line. Note that, if the TS is thin and space in the boat / mould permits, both sides of the TS can be used to increase the number of traces that can be made. A fresh TS might also be required - in which case the timber must be repositioned in exactly the same place from which previous traces were made.

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