epoxy or splinning a 1913 racing yacht

[pixelcraft]

I have a 1913 classic racing yacht whose hull is a carvel construction using Pitch pine. Each year I have painted the topsides only to discover that towards the end of the year the seams become more and more visible - especially once she has been lifted out and started to dry out.
She hasnt been splinned and is very good below the water letting very very little water.
My question is this - show I look to get the boat splined or is there a suitable epoxy filler that will flex enough so not necessitating a repaint each year?
many thanks
CR

 

[Peterduck]

You're obviously getting a fair bit of shrinking and swelling of the planking. Epoxy, or any other synthetic resin, will be far too rigid to cope with this movement. I would recommend raking out the existing stopping and replacing with a white polysulphide or similar "Caulking Compound". This should have sufficient adhesion ot stick to the planks, and yet have sufficient elasticity to adjust to the annual shrink and swell of the topside planks. Below the waterline is a different kettle of fish however. The moisture in the planks should be much more stable, as will be the plank dimensions. It is best to do the re-stopping when the shrinkage is greatest, so that for the rest of the year the stopping will be under compression rather than tension
Peter.

 

[Kukri]

Pitch pine does move quite a lot.

Stick with white paint and get a good fitted winter cover that comes down to the waterline.

 

[Tranona]

Splining is only suitable when the structure is very stable. Your flexible structure needs flexible seams! The very fact that seams open up as she dries rules out fixed splines or epoxy filler - which is rigid.

Suggest you try a polysulphide such as Boatlife, but you will have to rake out the old caulking first. The topsides should also be painted white as that minimises changes in temperature due to sun. It may also be worth considering keeping the boat in the water all year round, using a good vented cover over the deck and down the topsides during the winter. This will keep the moisture level more constant and therefore reduce the swelling and shrinkage of the planks. It also keeps rainwater off the decks which is one of the main causes of rot.

Modern yacht paints such as Toplac are more flexible than older style enamels. I would also be tempted to try one of the microporous exterior wood finishes such as Sikkens as these are very flexible and "breathe" to allow for changes in moisture content.

Hope this helps.

 

[pixelcraft]

Thanks for the replies - much appreciated will try the polysulphide.

thanks again

 

[KINGFISHER 9]

I'm using International Interfill 100 ... what used to be called Trowel Cement ... with a broad bladed putty knife thingy ... similar problem except iroko on oak ... leave it a couple of days if you can, rub it down wet with 240 wet & dry, then paint.

 

[pixelcraft]

Dear all
I have spoken with SP and they have recommended Spabond 370 - I have to say the guy I spoke to at SP was very very helpful. He provided me with an excel chart showing how boats heat up with different colours and a guide to using SP epoxies. After reading some reviews around polysuphide there would be a long cure time and needs temperatures to be above 70C - unfortunately I'm based in the UK /forums/images/graemlins/wink.gif

 

[Tranona]

Not sure where you got your information on polysulphides. Boatlife caulk which I have used for years is a flexible sealer and ideal for seams that move as a replacement for traditional putty concoctions which I assume you are using now.

The whole point is that boats constructed like yours are expected to move, partly because of the expansion and contraction of the wood members and partly because of the way it is fastened. The seams are there to allow for the expansion and contraction. As the wood swells the gaps between the planks reduce and the seam filler bulges out. As the wood dries, for example when you haul out in winter or the sun beats down on it all day long, the gaps open up and the seam filler can crack. This all happens without putting sailing stresses on the structure which can cause further movement.

Filling the gaps with a rigid filler - either thickened epoxy or glued in splines removes the gaps so when the planks move from either expansion and contraction or stress of sailing the spline or epoxy filler will just break away.

The only way to do away with flexible seams and the attendant cracking of the paint film is to totally dry out the whole structure and epoxy coat every bit of it to stabilise the moisture content of the wood. Then spline the seams and probably sheathe the whole planking with glass and epoxy.

Assuming you have the time and resources to do it properly and it works, you no longer have a 1913 classic racing yacht but a plastic boat with a lot of dried up old wood inside it - that just happens to look like an old boat!

There is a lot you can do to keep the topsides looking fair - most of which require hard work. Making sure all the fastenings of plank to frame are sound. That frames and particularly steamed ribs if it has them are sound. Caulking should be done properly so as not to put undue strain on planks or damage plank edges. Above all the structure should be kept in a way that stabilises moisture content - in the old days this meant laying up in mud berths with a tarpaulin over the whole boat. Today keeping afloat in a marina is just as good if not better.

Epoxies have their place in wooden boat building, but not, I suggest in the way you want to use them.

Sorry if it sounds like a lecture, but based on 30 years of wooden boat ownership and user of expoxy.

 

[Blueboatman]

Oh dear I am sorry to read that.
You are about to introduce an extremely hard medium (spabond 370) into the joints between a relatively softer and moving material (the planking) relying solely on the edges of the same planks to withstand any movement and shrinkage and allowing nowhere for any plank expansion to occur except by compressing the planks or unduly placing the framing in tension which <may> crack in way of the fastenings...(Something has to give doesn't it?)
I would be delighted to be wrong but when applying epoxies to old carvel boats, they invariably get the full treatment-ie sheathing in epoxy and glass cloth to create a uniformly distributed loading on the hull, in simple terms (and I am no expert)
Perhaps you would consider speaking to an experienced wooden boatbuilder or two and getting someone to have a look at the planking and its attachment to the framing/size of and number of frames before committing to what you are contemplating..
Myself? Sikaflex/polysulphide every seam and paint with one pot yacht enamel, making a neat slightly concave job of each seam and accepting that they will always show but will not crack open, whilst actually adding integrity and strength without risk to plank edges or frames through expansion..
Your boat,your choice, but I think you need more information from those who work with and repair old wooden boats

 

[Seanick]

A few points..

The paint on the inside of the hull needs to be as good as on the outside. This reduces the change of moisture content, and hence expansion and contraction of each plank.

Epoxy coating will achieve little more than good paintwork.

You could spline the topsides. We have succesfully done a few, but you have to follow some strict rules to get it right. It will preserve your topside finish and add longditudinal strength too.