The actual work took 2 days but there is some advanced planning to be done.

Prep

1. You need to take a paper/card plank template, of either an nsm2 or 4 depending upon your weight.

2. A sheet of 4mm Marine ply to replace the transom, you could use wood but ply is lighter!!!

3. two pot epoxy resin with filling, jigsaw or router (better I have one you could borrrow)

4. You need to take a paper/card plank template of your transom.

Work

1. With the boat upright, cut out the old transom, leaving the bit from the hog to the top where the pintles are and aprox 1-2 inches from under the rear deck going back to the pintal area. You can leave a small 1" down the planks to plank 4 as you will be cutting these.

2.On the transom wood that is left you will have (this is where the router comes in) take 4mm off the surface, not touching the planks

3. turn the boat over. as the next bit will be easer.

4. Cut down the plank joins (not the one attached to the hog) on planks 1 to 4

5. Now the cleaver bit. cut the transom that is left between the hog to transom support, and under the top pintal The hog should spring up about 1" and sit in a natural position. (i.e. reducing the rear rocker on the boat. it will also produce a very slight concave effect in the rear section of the hull, which was the same as in Mike Calvert's Charge of the Light Brigade.)

6. you need to put the two templates together, having the nsm2/4 on the hog area moving into your template around plank 3-3.5. if you can offer it up to the boat and adjust (tip use only half of the boat template) when your happy mark out plywood mirroring template and cut out, offer it up, and adjust. the planks will move a fair amount to fit the template.

7. Glue new transom in place using epoxy then add filling compound and run fillits all the way round the transom, along the planks (you might need to put some ply plank stiffeners on the thinner joins) and filling any holes.

8. Wait till it dries, cut new flaps, bung holes, cleanup and epoxy bare wood then paint, varnish etc

9. replace pintles and buoyancy.

Difference when sailing

The biggest difference you will notice is that the boat will no-longer build a powerboat wave before going onto and falling off the plane. It will just accelerate into a plane and sustain it longer, I also found that in surfing conditions it went down the waves very quickly.