Eucalyptus marine ply vs Okourne

[ridgy]

Thinking about building a pram dinghy to pass the time, specifically Dixi Dinghy and Argie 10 sailing dinghies

I know that ideally I'd get some Okourne ply from Robbins but I can get eucalyptus ply locally for half the price.

Any good? I think it might be heavier though I'm not building a masterpiece, just something the kids can mess about it in the future.

 

[PlankWalker]

Have no experience of eucalyptus ply but Okoume ply is lovely stuff, are there no cheaper suppliers up your way than Robbins.
Money spent on materials is rarely wasted.

 

[Motor_Sailor]

I had someone trying to use solid Eucalyptus wood to finish the interior of their boat and the problem was its tendency to 'check'.

I would confirm how stable the surfaces of the eucalyptus ply might be before investing a lot of blood and sweat in a project. I know what they call 'fir faced ply' in the States is completely unstable under paint, but is okay under a layer of tissue glass cloth and epoxy.

A couple of years after completing a boat building project, the commonest complaints I've heard from builders is that they wish they had used better materials and spent longer fairing and finishing.

 

[Wansworth]

Eucalyptus is great for making paper but very unstable............also a scourge on the Galician countryside!

 

[geem]

Our yacht is 40 years old and every bit of ply used in the construction was Okoume. Its very good stuff and stands the test of time. Its all I would use if going to the trouble of building a dinghy

 

[Plum]

Thinking about building a pram dinghy to pass the time, specifically Dixi Dinghy and Argie 10 sailing dinghies

I know that ideally I'd get some Okourne ply from Robbins but I can get eucalyptus ply locally for half the price.

Any good? I think it might be heavier though I'm not building a masterpiece, just something the kids can mess about it in the future.

There are many species of Eucalyptus some of which are twice as heavy as Okoume/gaboon so for the same ply thickness the dinghy will be excessively heavy.

Www.solocoastalsailing.co.uk

 

[C08]

I beefed up my rear bulkhead with 18mm marine ply that was Euclyptus plywood. It was painted with eggshell and 3 years later no sign of the the ply misbehaving.

 

[MikeBz]

As Plum says there are a lot of varieties of Eucalyptus. Some discussion of use of the Blue Gum variety in boatbuilding (not ply) here: Blue Gum as boatbuilding wood. There may be different varieties of Blue Gum as well. If this is just something for occasional messing about in then the actual wood might not matter too much, but obviously it does matter that the plywood (glue) is waterproof.

 

[ridgy]

Thanks for the comments chaps. I got a sheet of "marine ply" from another merchant past year and it weighed a ton but I've found a local source that publishes weights and this seems fine so I'll give it a go:

Marine Plywood 2440mm x 1220mm (8' x 4')

It's my first boat building attempt so I'm more interested in the process than the result.

 

[C08]

It was Atlantic Timber I bought my ply from, although as a bulkhead I was not too concerned about the odd void on my two 8x4 sheets but there were no voids visible at the edges at all.
I used the same ply (as far as I can tell ) to make new rudders for my cat when I first bought it ( 3x18mm ply and epoxy) 17 years ago and they are still pristine.

 

[John the kiwi]

When i built my 8 ft dinghy the plans called for 6 mm ply for the shell. Instead I used 4 mm plywood and put a single layer of 200 gm/m2 glass cloth on the bottom and up the the sides by 50 mm.
7 years on i can tell you the dinghy has survived being dragged up sandy and sometimes stony beaches in a way that simply painted ply alone would definitely not have.
Enjoy your project.

 

[C08]

After I did my bulkheads 3 years ago I left an offcut of the 18mm marine ply by the back door where it has sat well exposed to all the elements. It has just started to show signs of the laminates at the edges lifting slightly. I am not sure if this is very good or not? It is certainly better than a similar test I did on some rather expensive at the time, marine ply from a specialist supplier.

 

[DownWest]

After I did my bulkheads 3 years ago I left an offcut of the 18mm marine ply by the back door where it has sat well exposed to all the elements. It has just started to show signs of the laminates at the edges lifting slightly. I am not sure if this is very good or not? It is certainly better than a similar test I did on some rather expensive at the time, marine ply from a specialist supplier.

Sounds a good test, any ply will absorb water from the edges and the movement of the fibres will likely allow the glue to let go. I usually put a sample of ply in the dishwasher for a few days. Accelerates the test. Just tried some from the local B&Q at €24 for a 10mm sheet. While all the inner laminates are some soft wood, the glue is waterproof.
For my 15ft faering, I used Okume marine from a local supplier at around €60 for a 6mm 3.00 x 1.50 sheet. Very nice stuff and no regrets.
The owner of 'Watercraft' has been building a 19'6" glued clinker design in birch ply. Quite cheap and looked OK.