Only For Nutters – Part 6

Thinking ahead, the hardest part…

Building my boat on top of a hill might not seem the most sensible way of going about things, but it has had certain advantages: low rent, security, and proximity to home, which keeps travelling time and costs to a minimum so I can nip over to switch off the vacuum pump late at night. How to move the boat from the corner of its muddy field to the sea has been a constant topic of conversation, usually initiated by visitors and often with a smirk or a comment about Noah waiting for the flood.

The lanes in Devon are narrow and flanked by high banks and hedges. They can just about accommodate a farm feed lorry, but would never allow a 20ft wide catamaran to pass. Even mounted on its side on a flatbed lorry (terrifying thought!) the boat might be narrow enough but would stick up about 24ft high, way above telegraph wires and overhanging branches, never mind the logistics of such a balancing act.

Chocks away, Biggles!

So, if the boat won’t go one way, it will have to go another, as Poirot might have said. This part of Mid Devon is used by the military as a training area for helicopters, and they are often spotted playing a sort of aerial hide-and-seek, dodging behind hedges and copses. We have even seen Chinooks flying close by. More than one person has suggested asking the MOD to airlift the boat down to the Exe estuary as a training exercise. On the face of it a good idea, but there are snags even supposing they might be willing. Firstly, the airlift would have to be to their timetable, so I might have to wait a couple of months for a slot and then organise a lot of people in two locations at short notice. Secondly, who would accept liability for any mishap? And thirdly, what would happen if the pilots dropped the boat, even from a low height? I did enquire about the cost of commercial helicoptering, but was dissuaded by the starting price of £35,000!

Realistically the helicopter plan is a non-starter. Another suggestion, attractive if only for being off-the-wall, was, wait for it…. balloons, lots of them filled with helium! Not your little party balloons but the big meteorological type, just sufficient to lift the boat high enough so it could be walked across the fields by a group of us with long tethers until we reach a major-road pick-up spot for a large lorry. Imagine the fun and party atmosphere! And the calls to the police from motorists spotting low-flying boats and concerned about their mental health! And just think of the added excitement a little gust of wind could provide as we are wafted across Devon like latter-day Baron Munchausens!! The more we thought about it, the more complex and less attractive it got. Would we need a certificate of airworthiness? Perhaps a proper dirigible airship? Definitely a no-no.

Grounded again

This led us back to the original suggestion of constructing the boat so that it could be dismantled and transported in several pieces to a waterside location for final assembly, a lick of paint and the champagne bottle. Knowing that it would take a lot of extra time to do it this way had prompted the day-dreaming in the first place. Laziness, as my co-builder Andy has said on several occasions, is the mother of invention! And forward planning is definitely the mother of efficiency.

Having made our decision, we now embarked upon installing the major bulkheads in the hulls and working out how to make our kit of parts. The mast beam is designed rather like a railway girder bridge clad in plywood. The designer had suggested attaching it with a series of scarfs that would line up with the in-hull bulkheads and be glued together on final assembly. We rejected this on the grounds that making the scarfs accurately would be incredibly difficult and they would be vulnerable to all sorts of damage during construction and transport. We also wouldn’t be able to construct the corner joining the hull and deck, meaning that a substantial part of the construction would have to be left for later. It was decided instead to make a full-height double bulkhead and slot the beam into this, so there would be a generous gluing area and fitting would be as simple as possible. The hull-to-deck join at the mast beam has to be one of the most critical areas, so we reasoned that a little overbuilding here would be better than relying on a couple of dodgy scarfs. It also allowed us to glue and reinforce the bulkheads inside the hulls, without which no internal fitting could proceed.

Gluing a slot

But sliding a piece into a big slot presents its own challenges. If you smear glue over all the surfaces what happens is that it gets scraped off as the beam is lowered into position. Once located there is no way of knowing whether there is enough glue or a starved joint. The solution seems to lie in getting most of the glue in after locating the beam in position. So we plan to use syringes to inject thickened epoxy, with a series of tell-tale holes that will show when the glue has spread.

Of course there is a problem with syringes in holes, which is that they can bottom-out onto the inner surface and not inject, or slip out of their hole under pressure, or just squeeze the epoxy straight out onto the surface. Fortunately for us the medical profession has been there before, and little plastic nozzles are available to connect syringes so they don’t slip. (Try and search for female Luer connectors.) We will glue these onto scraps of ply before fixing them onto the bulkhead itself, then inject the epoxy and grind everything smooth later.

The aft beam at the back of the cockpit needs a different approach. This is constructed as a box, and will be fitted onto the bulkheads by being lowered over and simply slid horizontally into place. Bolts will pull everything together, and will ensure repeatable alignment.

A kit of parts

So much for the bulkheads and beams. In many ways they are the easy bit. The boat has to dismantle into sections that will be transportable and not too vulnerable to damage from lifting. We decided that making the cedar-strip curve for the hull-to-deck join was best done at the workshop, rather than rushed to completion under a temporary shelter. The deck and cabin floor are defined by short sections of ply composite and the cockpit floor will drop onto a stepped joint made by staggering the foam and ply. For now it will be left dry and provision made for taping over with biaxial at final assembly. The cabin will be done similarly, made rigid by the glued-in furniture and framing, which will eventually join to the aft face of the main bulkhead. In front of the bulkhead the fairing nose which gives it huge rigidity and strength will be attached before the move.

The cabin roof will be the biggest single piece, and will fit over the boat, lapping onto the hulls. This has been my main alteration to the original design, and is certainly the one element that will either make or break the boat’s looks. A smooth-curving carapace will be achieved using a temporary mould to support the contour balsa, which will be filled and glassed on the outside before turning over to complete the interior. The whole piece will be attached to the hulls using temporary bolts for location.

Balsa decks

Now we can make the smooth curve for the outside top edge of the hulls and start to fit the hull decks. These are made of ply, 20mm balsa and glass. Many people are suspicious of balsa for decks, because of the risk of water damage and rot, so we will make careful use of epoxy and oversized holes for fastenings. See Gougeon’s book on construction for details on this and the added strength it gives to bonded fastenings. One great advantage of balsa is its compression strength (greater than ply) which means that hardware locations do not have to be determined in advance. I am keen to decide on things like winch placement empirically, having seen several layouts that could have been much improved by shifting them just a few inches. This is surely where the homebuilder has the advantage over the commercial producer, who generally bonds pre-drilled aluminium plates into the hull at the specified location, so there’s no changing it later.

Another detail we have spent time planning is the toerail. At first I was keen to buy lengths of the anodised stuff – Antal and Goiot do some good profiles. But as the curvy shape of the hulls started to emerge, we realised that it would be difficult to bend them into the right shape. A composite rail is the obvious choice, constructed of foam and glassed onto the hull. The only awkward bit will be making the cut-outs and glassing them in advance. The rubbing strake will be done similarly, with a flexible PVC profile screwed into a section bonded onto the hull. No fastening will pierce the hull skin, so we should not have problems with water penetration. I am convinced that thinking about this sort of detail now will make things so much easier in the future.

The hardest part of any construction project is the management and planning. This remains true as I write, looking forward to one more year of construction. I need to construct the mast in the summer, making the best of the warm weather, and finish off the second fix (electrics, plumbing, painting, upholstery etc) over the winter, ready for launch in Spring 2008. So we have to get the beams in before April, and do the rudders in the workshop during the coldest months. Now where do we fit in the cabin roof?