During the last winter, a not inconsiderable number of owners have had trouble with plywood boats. There are several things readers who are contemplating building or buying plywood boats can do to avoid future trouble and disappointment.

First, obtain a copy of BS.1088, note carefully what it states concerning marine plywood, and check any statement made by plywood manufacturers’ representatives or salesmen. Second, check as far as possible that the plywood used does comply with the specification, and insist on replacement of any substandard material. Unfortunately, it is not unknown for BS.1088 and the B.S.I. kite mark to be stamped on material that does not meet the requirements of the specification. Third, if the salesman points out that BS.1088 plywood must withstand 72 hours in boiling water, ask yourself how often you propose to boil your boat, then ask the salesman what is the effect on the plywood of repeated wetting and. drying, and even more important, what is the effect of freezing wet plywood. Also you can remind the salesman that only a very small percentage of each batch of plywood is given the boiling test and the test makes no reference to any possible effect on the veneers.

Recently I bought a sheet of 12 mm. marine plywood, clearly stamped BS.1088, and with the B.S.I. kite mark, on which I found obvious defects. When I took this up with the manufacturers they said they would send their representative to see me. This gentleman arrived, six weeks later, without a copy of the specification, and tried to tell me that BS 1088 allowed open surface defects (which it most certainly does not). Further correspondence with the manufacturers resulted in the admission that "It can happen in a large production that an isolated board of - (plywood) may be, in some respect, slightly below specification". The word "slightly" is redundant. Either there are splits in the surface veneers or there are not.

Similarly with gaps in inner veneers. Clause 14, BS.1088 makes it quite clear that marking BS.1088 on a board is the manufacturer’s warranty that the board (NOT the batch) complies with the requirements of BS.1088. The sentence is therefore an admission that the firm's product is wrongly marked, and they render themselves liable to action. Of the last 11 boards made by this firm I have bought, nine have been unsatisfactory, and from talks with boatyard owners and shipwrights in this area, I gather that they have also found a disturbingly high number of faulty boards, and the "isolated boards" must make up quite a fair percentage of this firm's production.

I complained to the British Standards Institution about this misuse of the kite mark, and mentioned that I thought there night be a need for a new, more exacting specification for plywood for hulls and decks of cruising yachts. They informed me that BS.1088 is due for revision, and sent an inspector to see the plywood in question. This inspector was most interested in all I was able to tell him, and asked me to urge all yachtsmen and boat builders who come across alleged BS.1088 plywood which does not comply with the specification to notify the B.S.I. and hold on to the defective board until it can be examined.

The commonest faults to be found are open defects in surface veneers and gaps over .02" wide between the edges of joints in inner veneers. If all plywood users finding these or other defects write to the British Standards Institution, British Standards House, 2 Park Street, London, W.l. they will be able to take action, and the standard of manufacture of British marine plywood will rise with benefit to all concerned. I have no doubt the B.S.T. would also welcome comments on the adequacy or otherwise of BS.1088.

On the question of surface protection the manufacturers themselves appear to be in some doubt as to how important it is. A director of one of the largest British plywood manufacturers has written (on behalf of the Association of British Plywood and Veneer Manufacturers) "but the adhesives will prevent delamination even where, through rough handling or scraping, the plywood has been temporarily robbed of its protection". This was written in connection with the use of plywood for boat building and could be taken only as implying that unprotected plywood could be safely immersed in water for short periods. Later, when confronted with plywood that had delaminated through failure of the veneers, the same director wrote "if the water can penetrate through the faces or the ends, the same trouble can result and while it is sometimes more difficult to seal the ends, it is important to seal all the wood completely".

A warning to all who may be contemplating leaving a plywood boat out in the cold this winter. The above mentioned director also wrote "You ask us to confirm Mr. -'s statement that plywood which is saturated and then becomes frozen can fracture and give the appearance of delamination. This is indeed true……." Mr. -'s statement related to DAMP plywood, not saturated. The director has refused to answer a repeated query as to how wet the plywood must be for this trouble to occur.