Fitting a strake on a carvel boat
The best time to fit a strake is when it is still hot from the heat-forming and has just achieved the correct curvature. Proceed as follows:
- As soon as the strake has achieved the correct curvature during the heat-forming process (image 8) clamp it in the correct position against the ribs using the gluing clamps. Allow the strake to cool down in the correct shape (image 11).
- The strake requires further work before it can be fitted permanently. This work will take a number of hours.
- Slacken the strake again in order to be able to finish it.
- Now mark the strake using a marking lath along which you draw a pencil line (image 2). Clamp the marking lath along the underside of the strake (image 1) and check that the line is flowing (image 7). Plane off the excess timber using an electric plane (image 4) and (image 5) and then use the hand plane (image 6) to finish, until a flowing line is obtained along the pencil line.
- Using the brush apply plenty of linseed oil (image 17) to the strake located below, above which the new strake is to be fitted The linseed oil makes wet impressions at those places where the new strake touches the strake below it.
- Slide the new strake back into position (image 9) and secure it using gluing clamps (image 11). Hit this strake firmly using the mallet so that it is knocked against the plank located below (image 13). Hold a plank or piece of timber between the strake and the mallet so you don’t dent or damage the strake (image 12). Repeat this over the full length of the strake (image 15).
- Now slacken the gluing clamps and remove the strake again (image 18). You will now see from the wet impressions on the side of the strake where this has and has not touched the strake below it, in other words where the strake has ‘rested’ (image 24).
- Place the strake on its side on two stands. Use the hand plane (image 27) to plane away the wet spots (image 26). If a lot of timber has to be removed then use the electric plane but when using this make sure you do not remove too much timber.
- Repeat these steps (image 20) so that the strake has the best possible fit against the strake below it (image 23). This usually has to be repeated about 10 times (image 21).
- The matching faces of the two strakes must match up perfectly on the inside of the boat. On the outside a gap has to be left between both strakes in order to create a seam that can be caulked. The caulking will create a perfectly sealed seam and a watertight skin.
- Check the matching faces by coating the strake below the new strake again with linseed oil and knocking the new strake again thoroughly with the mallet and a piece of timber.
- Remove the strake again and check that there is a wet impression along the entire length on the inside of the strake. The inside of the strake will have ‘rested’ where it is wet. The outside of the strake will not have ‘rested’ and should be dry. The strake is only ready for fitting permanently once this is the case along the entire length of the strake.
- Put the strake back into position and secure it against the ribs using a few chipboard screws (image 28). Final fitting only takes place when the frames are deemed to be finished.
The marking lath will provide a flowing line
Draw a pencil line along the marking lath
Use the electric plane...
... but don’t plane off too much ...
... and finish using the hand plane
Be critical when assessing and working
Slide the strake into position
Clamp the strake ...
... and allow the strake to cool down
... with a piece of timber between the mallet and the strake
Hit the strake hard...
Is this fit OK?
Brush on linseed oil
Remove the strake again
Slide the strake back into position ...
Hit the strake again...
... examine progress with a critical eye ...
Linseed oil impressions on the side
... plane off the wet areas
Using the hand plane ...
The strake is ready for final fitting