Fibreglass boat transom replacement?

[Endacy]

Hi all, sorry for laucnhing straight in with a question as my first post! I bought a project boat about a year ago now - i've spent a lot of time making it useable and also quite a few ££'s too (the perspex and windows seals cost a fortune).

So far it's been fairly easy work, a new hatch, door, panels inside etc. Anyway the transom has always had some aluminium bent over it where the outboard was clamped on, i never thought much of it and figured it was to stop the clamps from damaging the fibreglass. However...

Yesterday i pulled it all off thinking there might be a makers plate underneath, and found some sticky glue and filler type stuff and some ali angle plating the top of the transom, i drilled / cut the rivets and found the transom was damaged and a piece of wood had been popped in to fill the gap. After removing all the metal and dodgy repairs i'm left with this:

The dirt type stuff in there is the heavily rotted remains of the wood in the transom (i didn't know fibreglass boats had any wood!). It appears the outboard probably hit an object and took part of the transom with it. It obviously needs replacing but i'm not sure if it's worth it / possible. The wood is/was glassed into the back of the hull and the motor well is in the way to cut it out, the well is moulded into the entire top half of the boat. You can see what i assume is the large transom wood spanning the rear:

Some ideas as to what i should do would be very much appreciated, i'm thinking i should probably salvage what i can of the boat ready for my next one and then sell this for whatever i can get. I'm concerned i wouldn't able to repair it properly or would hack it to bits and THEN realise i can't do it!

Thanks for any help

James

 

[Captain Coochie]

Quite hard to say without seeing but from the pics it looks like you could cut away the fibreglass from the top and get out any rotten timber and replace with a new piece of marine ply . You can then replace your outside timber and inside timber making the whole thing into a solid board that is incorporated into the body of the boat . Then fibreglass the bits you cut away and bolt the whole thing together .

 

[ArthurWood]

We had a similar problem on what is now my son's 19ft Wellcraft with Merc I/O. The transom had rotted around where the outdrive attached to it. We had a guy replace the whole transom, which involved removing the engine, so it was expensive. However the transom was replaced with marine ply and glassed in and is as good as new. It's important to first drill the mounting holes for the outboard, fill them with epoxy and drill again to prevent water ingress.
Good luck.

 

[twisterkai]

Just to clarify your post, the first set of holes that are drilled are done so oversize, ie, if its a hole for an m10 bolt, then drill to 14 mm, fill with epoxy, and then re-drill to 10mm, leaving a 2mm ring of epoxy around the hole.

Otherwise, agree with all previous posts. The repair, whilst initially looking awful to contemplate is actually fairly straight forward.

Good luck with it.

 

[Endacy]

Not too daunting a job then? I reckon it'd require me to cut to top half of the boat off at the back to be able to remove the motor well and surrounding area, then cut the old transom off from the hull, fit a new one and refit the top half, a lot of work and might look naff / not work too well. I'll have a think, it may be easier for me to find another boat.

Thanks for the help so far!! The boat isn't worth very much, i expect having the work done by someone else would cost more than it's worth.

James

 

[andy_wilson]

In for a penny...

It's not going to be worth any less if you hava a go at it and make a mess.

I agree the o/b motor well is a challenge to be avoided.

Don't disturb that, but instead cut / grind through the external transom gelcoat and timber, but don't go right through, leave the internal skin intact.

Grind back until you have gone beyond the rotten timber, and probably even it up both sides for symetry. Chamfer the cut edge of gel-coat and GRP between 12:1 and 20:1, ready for re-laminating.

Clean up the exposed inner face of the transom and prepare it to bond (or laminate) a replacement reinforcing piece of ply in using epoxy.

Glass over the repair, overlapping the chamfered edge and coat with gel-coat.

Smooth with wet 'n' dry, polish, drill, re-mount motor etc. etc.

If you get a good book on the subject and practice a bit you will find you can make a perfectly workmanlike DIY job of this. The key is to tackle it from the outside to avoid butchering al the internal mouldings.

If the engine HP is high, make sure you practice and become good at creating a strong wood to polyester bond. Bonding the new wood in to place using epoxy is not a problem, getting polyester (GRP) to bond to wood is a bit more of a challenge.

 

[andy_wilson]

Just to add...

If you take a sample of the outer lamination to a GRP supplier, they should be able to tell you what type of GRP mat, what weight, and how many layers to do the job.

 

[dog]

Hi, Been through all this a year ago- use epoxy (West or similar) easy stuff to work with and I got fantastic results from it. PM me if you need any more info.

 

[Endacy]

Re: In for a penny...

Excellent!! I think i'll take this advice and have a go at it myself, it'd be a shame to have to get rid of the boat, it's worth next to nothing really compared to most of your boats (from what i've seen so far!) but i like it's shape. I'll have a go at it Andy's way by cutting through the outer hull, replacing the whole transom board then glassing back over it. I'll look for a book about such things in the local chandlers or online. This way makes more sense anyway, considering the engine pushes forwards on the transom it seem logical that the internal fibreglass covering is the stronger and the outer one just stops the boat sinking!

Thanks guys, appreciated. If anyone else has had a go at this let me know if there's anything i should look out for.

Thanks

James