My first try at fibreglass repair...

[Greenheart]

It's a job for epoxy. It'll bond well to the existing grp (with a bit of roughing up) and soak into the wooden battens. May need thickening to bridge the uneveness. I prefer wood dust, others seem to like microballs.

Thanks for that...you're right, it'll need a thick gloop of powerful adhesive to bridge the gaps between wood and GRP. I had thought to add layers of tape & resin to the areas which flex, but a hardwood batten will be neater & better, as long as it sticks immovably.

I noticed evidence of old damage to both sides of the hull, in a position which suggests it was probably dropped onto its trailer, or took a road-hump at excessive speed.

There's a lot of filler and crazed gelcoat exactly where the trailer's port and starboard supports touch the hull. Sometime soon I'll fit the 5" inspection hatches I bought, and see if the damage needs extra glassing-over on the inside. Nice to know how to, now. Who knows, I may even go sailing.

 

[Lakesailor]

It's a developing situation.
There is nothing to stop you going for a sail. Indeed it may suggest other priorities or alternative remedies.

 

[Greenheart]

It's a developing situation.
There is nothing to stop you going for a sail. Indeed it may suggest other priorities or alternative remedies.

Indeed, with the thwart fixed and a touch more glassing on the other deck-split, I'll reckon she's ready to sail, although very untidy. I'll only have my old concern in mind, respecting the big rig and rather lightweight me...I can't count on SWMBO's attendance, so I ought to get a trapeze-harness. Like this chap, alone on an identical Osp:

 

[Lakesailor]

Looks fone I must say my Solo would have fallen over whilst I was clipping on or unclipping, if it had been a trapezing boat, of course.

 

[bljones]

Well done on getting your paws wet in the grp world. I agreree with Lake- epoxy resin is the way to go, rather than messing around with auto-DIY-style GRP packs. It sounds like you've got a few other jobs to do on your boat over time, so it might behoove you to buy a gallon of West and the appropriate hardener...and the pumps. Pumps make measuring foolproof. One pump of resin, one pump of hardener, mix with a tongue depressor, go to work.
Regarding brushes, use the cheapest brushes you can find, and cut the bristles down to 1/2" below the ferrule, then tug the bristles to pull out any loose hairs. Short stiff brushes are much better at working resin into cloth, and less resin is wasted on the brush.

Use margarine tubs, yogurt tubs, pudding cups, etc., for mixing resin- when done, stick the brush in the cup and set it somewhere out of the way and forget about it. That is how cleanup is done. When the resin has cured, grab the handle of the brush and pop! It all comes out of the cup in one piece- no fuss, no muss, no thinners or acetone or rags. Just a brush with hardened bristles stuck in a bed of cured resin and a clean, ready to reuse mixing cup.
Prank SWMBO by leaving one or two on tables throughout the house.

 

[Greenheart]

Good advice, thank you. The strength of cured fibreglass has had me speculating about household matters it could be used for...but I hadn't considered pranks, yet!

West epoxy isn't cheap, I seem to recall...so I believe I'll sail the boat and assess what's vital, before beginning another term of slow repairs at large expense!

I must say my Solo would have fallen over whilst I was clipping on or unclipping, if it had been a trapezing boat...

Very likely my Osprey's masthead will taste brine again and again while singlehanded...hence another thing I need, a decent masthead buoyancy device.

But I do wonder how it is that the Finn dinghy's enormous sail can be kept pointing skyward (by a hefty helm, hiking), while the much beamier Osprey's smaller main and jib test the righting ability of two grown men, one on the wire - in fact before the trapeze was allowed, it was raced by three-man crews.

My interest won't be in racing, so I'll reef or even row myself out of trouble if it turns ugly...but different designs' very different levels of tenderness do interest me.

 

[lw395]

The Osprey is known to be good for quite a lot of breeze.
It has 140 sq ft or so of sail compared to about 100 for the Finn.
Finns have bendy masts which depower very well, and also the rig is fairly low profile.
Finn sailors tend to be heavy and very fit.

Epoxy is expensive, but it is effective in highly stressed areas.
Ordinary polyester GRP is Ok for may repairs, it can be plenty strong, it just needs more contact area for a given strength than epoxy.
It also does not penetrate and seal wood so well.
For mixing either, I tend to cut plastic milk bottles in half, they are usually polythene which is OK with most solvents.
Margarine tubs are often some other plastic which dissolves in many things, I learned this the hard way.
Have fun.