marine ply boats

[jwood]

I am looking at an early 1970's, 23 foot cruiser/ racer that, to my eye, seems in sound condition. It is constructed from marine ply, though, and I would like some opinions on the durability of this material, particularly on a 30+ year old boat.

I have read some rather contradictory thoughts on a previous thread which I suppose is to be expected. It would be helpful to know what I might be buying into, though!

Thanks.

 

[snowleopard]

look particularly for places where fresh water may have lain for long periods. i had a dinghy that had rotted right through as a result of a previous owner not replacing a tatty cover.

 

[scottnewcombe]

My motor boat is marine ply below the chine. I had to replace the transom last year because of water trapped at the deck level causing rot. When I took the old transom off the ply was fine below the waterline.People talk about salt water 'pickling' the wood. Not convinced myself but I do know that all the rot I have found on my boat has been above the waterline. Maybe people tend to look after the bit that can cause you sink a little bit better?

Scott

 

[Talbot]

Bob Cats were made of this material, and I know of one that is in the middle of a circumnavigation at the moment and must be abt the same age.

 

[LittleShip]

The cabin and flybridge on my boat are marine ply, and it is true that it will suffer from the dreaded rot bug. The answer to this is to keep the ends of the ply sealed so that it wont wick the water in.
However if you find that there is some rot and it needs to be replaced............... its only plywood and an easy fix with moderate wood working skills and tools.
I stopped and was talking to a guy in the boatyard a few weeks ago who was repairing a marine ply cruiser, I asked how long he had been at it........................ since 1974 he replied, Oh well thats boats for you.
Good luck with the purchase. Remember plastic isnt all its made out to be either. IMHO

 

[Colvic Watson]

Had a marine ply boat a few years ago and can say that there were no problems below the waterline - perversely it's easier to keep it watertight as you rarely scratch the paint below the waterline. The parts that suffered were those around the cabin top that had bumps and scratches that let water seep in. Transoms are notorious because of the ninety degree angle between the hull and transom - means one end grain is potentially exposed. The great thing about ply is it is so cheap to repair / replace; it is also much easier to attach fittings & equipment.

 

[oldsaltoz]

G'day Witchwood,

There are still a few World War One pilot boats and mine sweepers getting about, so it isn't all bad.

Modern epoxy resins will provide a good seal on ends and edges, many of the older rigs have been coated with epoxy and a layer or two of rovings and faired with an epoxy filler, no reason why they should not last many years.

As others have stated they are not difficult to repair, biggest problem area is holes drilled and properly sealed prior to bolting / screwing on fittings. Check the chain plate bolts as they tend to move and elongate the holes after a few years of hard sailing, a good gouging and layup of epoxy and glass fixes this problem, some have s/steel plates glassed in to provide a good solid fixing point.

Anchor lockers can be a problem if not heavily lined to prevent damage to the ply, so have a good look inside.

Most rot will leave a brownish streak so can be detected, if the paint is fresh, start to worry.....

Andavagoodweekend.

 

[jwood]

Thanks for all your thoughts and experiences on marine ply - it's nice to know which areas need scrutinizing most carefully and what questions should be asked. I know that the transom and some decking has already been replaced - hope he did a good job!

 

[Spuddy]

rotten wood is spongey and sounds different when tapped - so try with a little hammer.
second test - poke a bradawl ( like a tiny screwdriver ) in to find soft bits.
Favourite areas are along chines, joints with keels, transom edges, where panels butt together, deck joints.
Plywood repairs are not that difficult - get it dry, make up templates for replacement panels and use epoxy. Problems arise if rot has got into chines themselves.
regards..spuddy

 

[William_H]

Yeah but fibreglass is great and will last forever especially compared to wood when neglected. Go F/G if you can it will certainly be easier to sell again unless your marine ply boat is very cheap. will

 

[graham]

Usually the decks and cockpit are the first bits to suffer.Also if the boat has been ashore with rainwater in the bilge it may be suspect.

Marine Ply comes in a huge variety of quality, the better quality stuff is very hard and is made up of lots of veneers.It must have been well built to have survived.

Ply boats are hard to sell and wont get a good price so if you really want it poke into every corner to confirm its not rotten then offer not a lot.