National 125 Sailing Association

125 Discussion Forum

Please note: This forum is read by a wide group of 125 sailors.
This is not the place for personal attacks or inappropriate comments on anyones race, sex, age or sailing abilities.



Return to the Forum List

Timber 125 repairs
I have recently bought a timber 125 and it has a series of fine longitudinal cracks in the ply on the outside of the flat section of the hull, running from the transom to past the centreboard. I have scrapped the paint back to bare ply and was looking for advice as to how to deal with the cracks. I thought perhaps the best way forward is to put a layer of glass mat over the area? I would appreciate any advice.
Michael Naughton9-May-2009    Edit    Delete 
Re: Timber 125 repairs
builders bog
hgftdsg10-May-2009    Edit    Delete 
Re: Timber 125 repairs
What you describe are stress cracks in the outer veneer of the plywood. There are 2 usual causes.
1. With successive re-painting the outer veneer has been sanded down to wafer thin and has no strength. Sheeve with a very light weight fibreglass cloth. A local fibreglass supplier can supply materials and advice.
2. The floor panel is flexing and the ply cracks when a strong point is reached, which does not flex eg. keel and seat sides. It is often matched with a crack on the inside of the panel. You must first stop the flexing. A timber across the floor battens under the thwart (only place allowed by the rules), attached to the seatsides & the centrecase works wonders. Then repair just the cracks as in 1.
Also check the front tank. Stress cracks are usually found in very early 125's where panel flexing occurs and is stopped by the keel and front bulkhead. Stiffen the panel with a strip of plywood glued in a "herring bone" pattern. This was added to the building instructions in later years.

I do not support the answer in the previous response as it will only add weight without strength. When the cracks return they will only be bigger.

Don Barnett, South Australia
Don Barnett10-May-2009    Edit    Delete 
Re: Timber 125 repairs
incorrect, on my old boat, i had those cracks yet no weakness in the hulls strength, on the tanks, it is where you have not opened your tank lids and in the heat, the tanks expand, and the air has no wehere to go, hence, breaking thro the wood
hgthejd11-May-2009    Edit    Delete 
Re: Timber 125 repairs
I had a similar problem on my timber boat. We sanded the hull back to bare timber, being careful not to take any wood off. we then coated the hull with a product called epiglass everdure. it is an epoxy based sealer that penetrates the wood. chances are the cracks are just in the paint from the flex in the hull.

But if when you sand it back the outer veneer looks a bit thin, refer to Don Barnetts comments above.

And you should never use builders bog, if you are going to fill/fair cracks, dents, use epoxy resin and Q-cells/micro balloons. it is much lighter, easier to work with and designed to work in the marine environment.

If in doube, contact the association in your area
Grant Steinback11-May-2009    Edit    Delete 
Builders bog is for houses not boats!!
Concur with the words on the builders bog, it is a heavy product, comparatively, and has no strength value in this application.

BB is just a polyester resin based product in a ready to use form, that under emergency repair circumstances might be considered if you had no polyester resin and Q cells. Outside of this, keep it to your house repairs at best.

Best bang for your buck is to sand the underside hull area well to both get some weight off and ensure a good bonding surface and then sheath the boat in a fine weave cloth with epoxy resin.

Normal width cloth only manages to marginally wrap around the widest section of the hull chine to chine but will stiffen the hull considerably.

Depends whether you can afford the time and work and there may be a slight weight gain but a considerable stiffening of the hull.

Good luck.
steve low16-May-2009    Edit    Delete 
Re: Timber 125 repairs
I am about to repaint/repair an old wooden hull and am considering the above mentioned fibreglassing technique. Does the wood need to be sealed prior to glassing? I'm assuming that cracks and gouges etc need to be filled prior to glassing. I'm considering the Norglass range of products (Norfill, Norseal etc) are there other similar or better products?
Steve Baigrie26-Aug-2009    Edit    Delete 
Re: Timber 125 repairs
Steve,
That would depend on the condition of the timber, a coat of epoxy before glassing to allow the timber to soak up the resin is probably a good idea. this will prevent the timber from sucking the resin out of the glass tape. However it is probably a good idea to seal all the timber, with a product called epiglass evidure. this is a deep penetrating epoxy based sealer that will also protect the timber.

The best thing to do is to ask at your local chandelery, the guys there have usually built and repaired boats and are a good source of advice.

The norgalss products are very good, I have used the pait on all but 1 of my boats (the one before I discovered it) and it is almost indestructable!

Hope this is helpful

Cheers

Grant
Grant Steinback26-Aug-2009    Edit    Delete 

Return to the Forum List       Add a message to this discussion
Measurer's Forum
Committee's Forum

  National 125 Association admin