Sunday, June 25, 2017
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Fixing up your boat

Building Luvvly Jubbly (a wooden 505)

By Rupert Maynard


In January 1991 I started building a wooden 505. I had wanted to tackle this project for several years but there was never, it seemed, time, space or the money. However these were eventually put into place with some planning and I rented an ideally sized boat shed in Essex. About one and a half times the length of a normal garage and wide enough for a 505 with a bench down the side - the size meant that through the winter I wouldn't be heating any more airspace than was necessary to set of the Epoxy glue.

Why build a wooden 505? Because wooden 505s had always been stronger and remained rigid longer than fibreglass which emerged in the 1960s. The demise of wooden boats was brought about by the comparative cheapness of fibreglass construction, the drop in maintenance and wooden boats often came out overweight.

The original builder of 5o5s was Fairey Marine and these were hot moulded (hull and side tanks) on a male mould, a construction method pioneered during the Second World War for building wooden aeroplanes.

Other boat builders wee commissioned such as Tormentor who built 5o5 number four for the late Richard Creagh-Osborne, and Jeremy Rogers of Lymington who is reputed to have built the most beautifully finished 505 ever. Malcolm Goodwin of Wivenhoe in Essex built his own wooden hull, cut his own sails and came fifth in the National Championship in 1976. He went onto build 5o5s from time to time into the mid eighties but often ran into the old problem of finishing overweight. Also Dennis Trott built a few wooden boats around 1980, one of which was for Lawrie Smith which was again overweight by about 19 kilograms.

I figured that with the advent of Epoxy resins and new plywoods being used instead of veneer I could make a hull as strong as the original with about a 40 per cent saving in weight. It was usual for hulls to be moulded out of 1/8 inch veneer, three layers throughout with an extra two layers strengthening the hull below the waterline to improve planing properties. I was advised (I had not done any woodwork since school where we made useful things like lavatory paper holders) to use either Gaboon Mahogany or Sapele and was able to source 1.5mm 3 ply Gaboon. Being twice as strong as 1/8 veneer, thinner and with the extra bonding properties of Epoxy bonding the 100mm strips would make a stronger and considerably lighter composite.

The first layer of diagonal strips was followed by 5mm cedar slats running fore and aft for below the waterline strengthening. The second layer of Gaboon (the native name of an African river where this very light but strong strain of Mahogany grows) was then cut, trimmed and put in place and after 100 hours the hull was moulded. The strips were stapled into a female mould that I bought from Malcolm Goodwin and modified, the female mould had the advantage that the bulkheads, centerboard, transom and decks could be fitted into the hull whilst still being held rigidly.

The next step was to cut the bulkheads and form the under-the-foredeck spinnaker chute which was an innovation by Malcolm Goodwin and much used by other builders as it incorporates the material of the chute into strengthening the area rather than hacking through existing bulkheads to add a chute.

To the inexperienced wood worker extracting shapes from the hull to cut the bulkheads was a time consuming process and I soon realised that my estimated building time of 200-300 hours to completion would be more like 400 hours.

Building the mast step I panicked as I added up the forces that it would be enduring, a massive load from the rig tension trying to drive the mast [through] the bottom of the hull, the sails levering the mast foot down and aft to say nothing of these forces then being doubled or trebled by impact from strong gusts or pounding in a big sea. I spoke to Paul Young, who said we were talking about tonnes of compressive load but that my design would take it. The first time we flew the spinnaker in a force 5 I had to close these figures from my mind and sure enough we accelerated into a plane without a grunt or groan from anywhere in the hull.

To save weight in strengthening I took the main cockpit bulkheads back to the shroud positions to disperse the load and a wooden strut from the shroud position to the thrust face of the centerboard case the idea being that the pinching effect of rig tension on the hull would be opposed in strong gusts by the leverage of the centreboard and the rigidity of the centreboard case.

Nearly all the bulkheads and decks were of 3mm ply which proved a little flimsy for the side tanks but I was still worried about building the boat overweight. By April I had not missed a weekend in the boatshed and she was ready to be released from the mould.

It took five us around three hours to prise her free. Without fittings the bare hull weighed 65 kilograms and I was delighted as I had fretted once when going through the delivery notes, I added up the weights to 155 kg, was there more than 60 kg of scrap wood and sawdust on the floor? And how much of the 20 kgs of epoxy was in the hull?

The building so far had taken 400 hours and I still had to fair the hull and could now add fillets and gussets to strengthen her where I had skimped to save weight.

At this point I developed a rash and became nauseous whenever I went near the boat, initially I thought it was a virus but the rashes turned to gushing water whenever I used epoxy. A few days later I went to the Doctor when I became covered from head to foot in the rash. He diagnosed eczema caused by excessive exposure to the poisons in the epoxy from both skin contact and inhalation.

I painted and varnished the boat with epoxy-based and collapsed for a week when it was done. I had stretched my immune system to its limits and it suddenly could take no more when the eczema broke out, apparently only some people become sensitized to Epoxy and often this is linked to hay fever sufferers. The other strange thing is that the resistance became less on further exposure and I now have an immediate reaction, staring with puffy eyes, to the slightest amount of Super Glue or Araldite. I visited four dermatologists and researched the condition through the National Eczema Society and there is no cure.

I fitted out the boat and left her alone for two months whilst I crewed an Ultra 30 for the summer. I was very lucky that the eczema subsided as it usually remains for years once established.

Mike Bees from the International 14 fleet and I raced the boat in the Travellers Series at Grafham and she held together in strong winds and showed a good turn of speed but even with wind and water washing over the decks I still had a skin reaction.

However it was a great moment in my life when we crossed the line sixth in one race and I felt the project was a success.

She needs some minor modifications to complete her but I am unable to tackle them and am looking for someone to undertake the project as a wooden boat will always need some attention.

In raw materials the finished hull cost around UKP 500, the mould UKP 100 and heating and rent about UKP 400, my labour totalled 500 hours which second time around should be more like 150-200 hours.

Lubbly Jubbly is the second wooden 5o5 I have sailed in. I think that they have very different feel and are faster when down to weight and they the best with varnished decks. Alas, every rose has its thorn.

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