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A Plea For Continued Weight Reduction

By Robin Steavenson

This season (1970) sees the end of five years of planned weight reduction and nobody can say that it has been other than successful. This courageous and far-sighted policy of six or seven years ago has in no way affected the quality of our racing or produced less sturdy boats, and it has shown that annual performance improvements are marginal only with such small weight reductions. Indeed until such time as all crews and helmsmen weigh the same and wear the same clothes, plus or minus a few pounds in the hull, weight is almost immaterial. Nevertheless lighter boats are an enormous advantage to those of us who have to carry them over rocks to launch, or trolley through loose sand, or load single-handed onto trailers and, of course, taken over a big span of weight reduction (20-25 lbs.) lighter boats obviously perform better than heavy boats. One wonders, therefore, if we should not continue our weight reduction policy for another five years at least.

Looking back over the post war period shows that the weight reduction has been enormous and there is no evidence that it has spoilt the racing indeed we have better boats now than we have ever sailed in the past. In 1946 the bare stripped hull weighed 225 lbs. The steel centreplates were all about 45 lbs., and air bag buoyancy was not developed (except for some crude ex-service bags), so most boats carried four copper tanks weighing about 4 or 5 lbs. each. All boats had floorboards over their ribs, which weighed not more than 5 lbs. Thus for practical purposes the minimum’ hull weight was 295 lbs. and usually a lot more, as no one was weight conscious.

In the late 1950’s and early 1960’s the rules were amended so that the concept of an all-up sailing weight was introduced. Because buoyancy was becoming built-in, all buoyancy apparatus was weighed together with the hull, as was the centreplate, which later changed from steel to alloy. Thus, although the boats still officially weighed 225 lbs., the effective sailing weight had been reduced by some 70 lbs. and there were no complaints.

In 1965 it was not possible to proceed further with these rule alterations and so a positive policy of removing 5 lbs. per annum was instituted for five years thus reducing the weight from 225 lbs. to 200 lbs. in 1970 and this is where we stand now.

It is, however, obvious that unless some of the construction rules are changed it will be difficult to build boats much lighter than at present. We should therefore again review our rules, some of which date back to 1936 before marine plywood and synthetic glues existed, and ask ourselves if there is any logic for the continuation of such rules in 1970.

The first of these is the skin thickness rule (2B(h)) calling for uniform thickness of I in. (6mm) throughout. In 1936, ¼  in. thickness was considered reasonable for simple spruce and mahogany planking, but surely now with marine ply we can venture thinner for most of the planks in our boats? The Mirror 14 is skinned in 4 mm ply. With our clinker construction giving double thickness every 6 in. I suggest we would have ample strength from 4 mm ply for normal use except possibly the trolley bearing points where there could be reinforcement. It is said we could take 20 lbs. of weight off a hull by partial building in 4 mm plywood.

Several one-designs vary their skin thickness according to strains imposed. Therefore if we amended or discarded this rule we could nave 4 mm topsides, and if we so wished 6 mm garboards and bilges or locally re-inforced planks. It seems ridiculous to have thick planks where thick planks are not needed.

The depth of hull rules (1 C (i) and 1 C (ii)) date from 1936. This was before the days of suckers and wet suits when there was some sense in keeping a hull dry, but do we need such high freeboard now? I think we could build the hulls at least one plank lower and so save both weight. windage and cost. Wide hulls which scoop up water might have to accept narrow side decks amidships but this is a problem for the designer not the rule makers, whose job it is to open channels for development. We might even amend the continuous sheer rule (2A(c)) or even delete it.

Since we now allow unlimited suckers and large transom drains to take water out of the hulls, is there any sense in saying that no surface within the hull may divert water overboard? (Rule 2A(e)). Small holes through the planks to drain water from buoyancy tank tops seem perfectly logical if we allow extensive drainage from the rest of the boat. By allowing drainage from a forward buoyancy tank top we may well dispense with the weight of a foredeck and its beams, which have to be strong enough for crews to sit on when coming ashore sometimes.

There may inevitably be some feeling from the G.R.P. enthusiasts that they will have difficulty getting their boats down to weight but this should not affect our policy as the rules must allow boats to be built economically with the lightest material obtainable. The G.R.P. people will doubtless rise to the challenge, and in time materials other than G.R.P. and wood will become available.

I therefore make a strong plea that at our next A.G.M. we should decide to continue our weight reduction policy for another five years, and that we should ask the committee to amend the plank thickness and uniformity rules, and the depth of hull and sheer rules as soon as possible to enable future hulls to be more easily built down to a lower weight.

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