RS300 transom

You need
angle grinder
carbon cloth (check the class rules don't get funny about carbon repairs though)
some cheap glass (even chopped stand matt OK)
epoxy resin
peel ply
parcel tape
several pairs disposable gloves
sharp scissors your mother doesn't want again.

There are lots of ways of doing this, but I think I'd make a little mould...

Remove rudder fitting.

Put your broken off piece back, cover the entire area with parcel tape, and using your cheap glass make a moulding over the area. This needs to be pretty thick to be solid, use about 10 layers of the stuff. Leave to cure, then pull off. You'll use this later to get everything level. Cover it with parcel tape.

Now take the broken bit off. Using a small angle grinder or a file grind back the laminate. You want to start just below the top screw holes of the rudder fitting (these are best left untouched so you can locate the fitting) and grind back so that it is chamfered getting to all the way through at the crack. You should end up with a vaguely oval area of decreasing thickness of laminate. Leave parcel tape on all the surrounding structure.

Now take carbon cloth. You will use several layers of this to fill back the area you've ground out. Each layer a bit larger than the next. Measure up each piece, wet it out with epoxy, and put it on. Each successive layers should have the fibres at 45 degrees to the one before, eg one cross wise, one up and down, one crosswise etc It will compress down enormously when you've finished, so should be well above the local surface as you put the last layers on. I wouldn't be suprised if its 6 layers. Now add a layer of peel ply - maybe two or three. Now clamp your mould down over the top. You'll need to arrange something to hold it in place firmly.
Leave to cure.

Remove mould
remove peel ply

If laminate is well below the surface or the rest of the boat go back and add more layers or carbon, if its within a millimetre you're OK.

When the laminate is at the right height fill any holes or low points with filler and epoxy, sand down any high points

Remove parcel tape with squished out epoxy on, double check surface now absolutely level with the rest of the transom and correct if necessary. Drill the two new lower holes for the fitting, paint white, bolt on fitting again.

While this isn't an especially hard job its got muchos hassle about it. Possibly not the best task to be your first epoxy/carbon job.

Alternatively you could ring up RS and ask for a price. You're hardly going to have the first boat that has hit a rock with the rudder blade and bashed the transom a bit... You'll probably end up paying 60 quid to get all the materials you need, although you'll also have 90% of it left afterwards, so if they charge anything under three figures its probably worth getting them to do it.





Edited by JimC

Don't use epoxy on a polyester built boat.

Carbon and peel ply are unnecessary.

Other than that Jim's description should work

 A friend of mine suffered the same fate and sent the boat off to Winder. I have a feeling the repair was the best part of £500, however, most of his transom had gone!

Originally posted by Paramedic Don't use epoxy on a polyester built boat.

Why not?

If I did it I wouldn't expect it to break again unless I hit something very solid. But it would take me quite some time - at least a couple of hundred quid at pro boat builders rates.

I should have said - do you have good access to the interior of the boat? I can't remember quite how the 300 is laid out. If I could get tools in to seriously sand down the inside of the transom (if you can't significantly abrade the current surface this isn't worth doing because the new laminate won't stick well enough) I'd put a patch of a couple of layers of carbon about 200 * 150mm over the whole of the fitting area and overlapping onto the bottom of the shell which, together with the outside repair, would end up stronger than new, if a few dozen grammes heavier.