Shipwright John Owles warns against laying timber decks on plywood

Rotten timber from a timber on plywood deck - John Owles shipwright

Rotten stuff from the timber and plywood deck of Antares. Scary, isn’t it?

Cornwall shipwright John Owles has issued a stern warning against timber-on-plywood decks: the commonly-used technique of laying timber decks onto a plywood substrate is doomed to failure.

‘Have one or the other type of deck construction but do not mix the two,’ he says to anyone considering a big repair and restoration job.

John makes his point on a web page reporting on restoration work he did on Antares, a 55ft schooner that was in his yard a little while ago. Her decks consisted of teak planking reclaimed from an old steamer laid onto a plywood substrate and payed with a polysulphide rubber – and the result was widespread rot.

The choice is clear, he argues: if you want a traditional-looking deck then lay a proper traditional deck using fully dried timber. Otherwise lay an epoxy-glass sealed plywood deck and paint it with a two-pack polyurethane sprinkled with glass beads for grip.

With timber on ply decks, it is almost impossible to achieve a good seal, even when the substrate is coated with epoxy.

This is particularly true where fastenings pass through the timber planking and plywood: ‘When a hole is cut in plywood it exposes 360 degrees of end grain, so every layer is at risk of absorbing water.

‘When moisture is trapped in these mid-layers where there is no air circulation, it is impossible for it to dry out… creating an ideal climate for any spores to become active and so the risk of rot is ever present.’

In building a deck, try to avoid anything that allows hidden water to hang around, he adds, and keep your vessel very well ventilated, especially when left unattended.

See John’s website here:

Schnellboot S130 in restoration at Roving Commissions

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Schnellboot S130 - the last remaining Schnellboot or E-Boat

The last remaining viable example of the feared German Schnellboots, S130 has been in restoration at the Roving Commissions yard at Southdown in Cornwall for some time.

Roving Commissions is run by John Owles, the man who identified the wreck of the historic yacht Scoter as a bawley type. Read more about Scoter.

The 35m torpedo boats had three 2500hp engines a maximum speed of 40knots, and it turns out that S130 was a particularly successful example. Commissioned in the autumn of 1943, she was part of the 9th S-Boot flotilla that in March 1944 found and attacked the American invasion force in Lyme Bay during Operation Tiger, the D-Day preparation training exercise at Slapton Sands that ended in the deaths of more than 740 American forces.