plywood sailboat where are the week points.?

[justdrifting]

Ive just found several ply boats in a yard.One has had the deck riped off and is full of dead leaves!

The others are still covered but have been abandoned for many years.Two are small day sailers with a small cabin there about 18 feet,with a tastefully raised cabin across the full beam.

It has a "dingy" mast & rigging ideal for canal /lake sailing, a small fixed keel gives about 3 foot draft so far the price seems alright depending on the cost to move it?

What are the weak points on a small ply sailboat?

I will tap the hull looking for de-lamination check the ribs for rot.This one is screwed along the chines and hood ends is the ply glued as well?

I havent looked inside yet what should i give special attention?

 

[Spuddy]

I did a small scale renovation on a friend's Yachting Monthly Senior - ply chine about same length. Rainwater had caused rot where it lay on the stringers and then spread into the ply skin. This type of construction is not cooperative to repair. It was a right fiddle to scarf in new bits of stringer and then to patch up the skins. The rot hadn't got in the keel for some reason - if it had then some parafin and a match would have been the best solution. My suggestion is to have a VERY good poke around with spike and hammer looking for soft spots. When you find them think carefully about how you will repair them......and don't be at all optimistic !

 

[justdrifting]

Thats about what i thought,i was given an optimist two years ago,that looked "do-able" but once i got the bad patchs cut out the delaminatin lead further and further as well as to the stringers.

Before i ask about takeing one or all i want to be ready and know what im in for.

 

[jeanne]

I once had to repair a ripe patch on a ply hull. I did all that I could to find the extent of the rot. Tapping, drilling little core samples, and so on. Then I went a foot or so further than where I thought it was sound, and cut the rot out. There were still signs of rot in the centre laminations of the ply, hidden by the sound outer layers.
I guess it would have been years before it went from that to the point of being a structural concern, but it did not seem to be a worthwhile project once I knew there would always be rot in it.

 

[oldharry]

Plywood boats are great because they are completely repairable by anyone reasonably able with woodworking tools - no great skills required.

The three you describe will, by the sound of it, need completely repairing.....

Anywhere rainwater has gained access will be rotten. This means the bottom sheeting will have to be replaced. Almost certainly the rot will have extended into the keel and frames, so they will have to come out.

Notoriously rainwater gets between the gunwaling and the sheeting causing it to rot away, also it will penetrate the end grain of the deck sheeting causing that to fail, so the topside sheets, the gunwale, and almost certainly the adjacent frames will need to come out. Deck sheeting will need to be replaced.

Cabins notoriously leak where they meet the deck, the roof sheets will rot wherever any fixture or fitting has been fastened into the timber, hatch joints will be loose and allowed water penetration. Deal with that lot and you have a nice new boat!!!!

Its actually cheaper to start again and build from scratch.

Or maybe its perfectly alright!

Look anywhere where the ply sheets are joined or pierced by fastenings. Any ply edge is suspect. A properly constructed ply boat will have all the ply edges either covered by solid timber, or have capping pieces attached to protect the edges. Transoms are sometimes built up composites - my old Bell Seamew had a curved transom made of three sheets of ply glued over the frame to get the shape. One glue line had failed (never been made properly?) and we could run a blade right down the transom middle, although externally it was fine!

Anywhere rain water has stood will be 'dead' - particularly when mixed with old leaves to hold the moisture in.

Once you have assessed the extent of the damage to the hull, treble it. I am quite serious about this - for every bit you can see, there will be two more bits you can't see. If you are lucky!

Basically an old plywood hull is very rarely worth bothering with except as a pattern and source of fittings to build a new one from scratch - if you really want to!

There are some good plywood hulls still around , but anything over 25 years old, unless rigorously maintained or sheathed with cascover or similar from new, is at or near the end without massive amounts of time and money. All joints in a ply hull MUST be glued, and the glue lines must remain sound. Sometimes it is possible to clean out old glue and pour in epoxy to remake the joint without dismantling it. More often you just end up with epoxy everywhere except where you want it!

Mostly, old ply hulls just need my "bigger hammer".... or a JCB to break them up!

And above all else walk away very quickly from anything that has been 'glassfibred' . Polyester resin grp sheathing is about the quickest way there is to destroy a wooden boat, short of setting it alight or sinking it! Polyester does not stick to wood for long, damp penetrates the failing joint and provides ideal conditions for rampant rot.

Good luck! You will need it.....

 

[alistairedw]

The covers can cause a boat to rot away quickly. They keep the rain out but trap atmospheric moisture so that the wood is not able to breathe. If the covers have not been removed occasionally during fair weather there will be lots of soft wood around.

 

[Lakesailor]

I restored a 50 year-old Heron.

It had been 1 foot full of rainwater for some time. I wish I'd put a match to it.

Frames will be soft around the hog/frame joint. Also around the the frame/deck beam joint. These can be repaired with a "pouring" technique using epoxy (or replacement).
Ply hull bottoms are the worst affected areas, especially near the hog. Replacement again, if they are scarfed together it's pretty easy if using epoxy (plenty of wood flour to form a stiff filler)
http://www.lakelandimages.co.uk/Forum%20pics/AANov/New%20Folder/

Old and de-laminated ply can be restored to a certain extent with thin epoxy. The advantage of ply is it's suitable for epoxy repairing, whereas solid wood moves too much.

It's worth it in the end http://www.lakelandimages.co.uk/heron

 

[blackbeard]

There are plenty of plywood sailing dinghies about 40 years old still in fair condition (including my GP14).
Depends very much on how well they have been looked after. Being left with standing fresh water, or with no ventilation, is seriously bad!
I imagine the same applies to small cruisers.
Take your time, there's plenty to choose from.

 

[justdrifting]

Thanks for that,plywood dose seem to have a downside.Its a pity as these are quite practical boats,light small but comfortable and ideal for "trailor sailing" canals lakes and coastal.

In these days of high costs and crowds i though it would be a "summer solution" leaving the med to spend summer in less expensive hot & humid as the med which has a new trouble "the mosquito"

In France there are many large lakes which do suffer from the ski jet but might be fun to explore just as there are rivers (Charent) or canals such as in Belgium where there are less restrictions no vignet and first class food good woman and French wine all in a relaxed uncrowded atmosphere

Such a programs impossiable with a conventional boat that has to travell on her own keel i thought these might prove to be a sort of delux tender!!Easy free winter storage and a free summer place for summer(very hot dusty and boreing if abord)

Imgoing to look with a hammer and stout spike!And of course as there at an afordable price (free) be hopefull.

I have re read your post and will walk away if theres doubt as to move it and pay the yard costs while repairing prepareing before fitting out wont be free!!!

I have a riva rowing boat being Italian it has an 8hp and can have a 20hp but no sail! Varnished dingys look great as dose lake sailors Heron must have put in a lot of work.

 

[Lakesailor]

Not hammer and spike. Just press firmly with your hand where you would expect it to be firm and if it flexes too much, that's a sign of de-laminating or rot.
drumming on the ply with your fingernails will produce a booming noise on good wood but a dry tap-tap noise on poor wood.

Yes I put in a lot of work and then sold it, bought it back, and a year later sold it again.

Be warned. If you make too nice a job of it you become paranoid about launching, mooring, taking the beach, rain etc etc.

 

[justdrifting]

Oh yes!

A spike through ply perhaps wouldn't be a good idea?Though as the boats are abandoned wouldn't a spike pressed against the inner or outer ply push through with ease if the inner plys have delaminated?

Ply always worried me when i heard of Plywood manufacturers would leave voids or use very poor core laminates at times

I quite enjoy varnishing once the preperations done!As each new coat looks better

Your new dingy looks really great

 

[Boatmik]

[ QUOTE ]
The covers can cause a boat to rot away quickly. They keep the rain out but trap atmospheric moisture so that the wood is not able to breathe. If the covers have not been removed occasionally during fair weather there will be lots of soft wood around.

[/ QUOTE ]

Covers need some air gaps too. The biggest preventative of rot in any wooden boat is ventilation.

Michael Storer

 

[Boatmik]

Howdy,

There's a lot of doom and gloom here - and some of it might be right - it depends on the boat!

The comments about avoiding boats that have been fibreglassed with polyester resin are very accurate. But if fibreglassed with epoxy then that can be very good.

There comes a point with all construction methods where there starts to be so much to do that it is easier and better to start again.

However - if you want to look through the restoration threads here you may be able to find some cases where people have gone through the process very successfully.
http://www.woodworkforums.ubeaut.com.au/forumdisplay.php?f=29

If your interest is to get a CHEAP boat - the only way to do that is usually to find a boat that is a going concern.

Any boat bought without major parts, sails and complete fittings will be expensive to get going again unless you are VERY knowledgeable about sailing and at least simple boat maintenance.

I have restored some older ply boats into good working condition, but I make sure everything is there in the first instance. So if I spend a week or two or a month fixing a hull it can be very worthwhile. But you do need all the other bits to be there in good working order.

Otherwise it is simpler and cheaper to build from scratch from a good detailed plan like those from Iain Oughtred or similar. The detail of the plan is what saves labour and materials to get results much faster than fixing an old boat up.

After making sure everything is there you need to have a good look at the hull or maybe even pay a surveyor or a reputable timber boat repairer to have a look at it and make some suggestions.

I have a bunch of articles, some dealing with boat restoration here
http://www.storerboatplans.com/Faq/faqindex.html

I have a few articles of repairing and restoring