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Pro Tunnel Race Boat Plans
Page Ten
Deck, Lifting Beams and Flotation

The deck, of course, is longer than eight feet, so will require a scarf joint. I chose to put the joint nearer the stern so that it didn't get mixed up with the "split" in the deck caused by the raised sponson.

Fitting the deck starts with cutting the slot. Then trace along the upper side and along the carlin. To help trace along the carlin I taped a pencil to a batten which enabled me to reach in under the plywood.

The deck cut to size. Leave some extra length at the transom, to be trimmed later after the coaming is installed and the extension of the tunnel is framed.

Now put your deck pieces aside, and let's get to take care of some other essential matters.

Boats raced in sactioned races will need to meet minimum weight requirements, which means they must be hoised onto a scale. Two of the lifting points are located near the driver's seat. (The other two will be on the motorboard and are discussed below.)

On either side of the cockpit, spanning the distance between bulkheads two and three, a 1.5" x 3.5" beam is installed as shown. The beam will be just outboard of the coaming; in fact you may end up cutting away a bit more of the coaming in the vicinity of the u-bolt lifting ring.

Fit the piece snuggly to the curve of tunnel plank, and install it right up against the tunnel batten. I also drove a long screw through the beams at Bulkheads Two and Three and into the ends of the lifting beams.

Furthermore, add some cleats at either end to tie the beam to bulkheads two and three.

The idea here is to tie this beam to as many parts of the boat as possible so that when the boat is hoisted it will not simply be torn out. Each lifting point will have to withstand one-quarter of the 650+ pounds (162.5 lbs.) required for GT Pro (including the driver, who will be aboard during weighing).

While we're on the subject of the lifting rig: The other two lifting rings will be mounted on the motorboard. Shown here on my Dillon Pro Vee.

You probably will want to wait until your motor is mounted on the boat before installing these lifting rings, to make sure they are not in the way of anything.

You will also need three cubic feet of flotation for racing, which should be enough to float 180 lbs. Of course flotation is a good idea for non-racers as well.

I put my flotation in the spaces, on both sides of the boat, between bulkheads three and four and outside the tunnel sides. Seal these areas with epoxy first.

You will want to line the space with plastic to prevent the foam from adhering to the hull -- after the foam has cured, it will shrink somewhat and will distort whatever it is bonded to.

Mix the two-part pour foam according to the manufacturer's instructions. Do each side with three or four batches so that you can best fill gaps.

Where it rises up above the deck, it can be trimmed away with a handsaw, and further pared down with a power sander. You may also have to cut some channels through the foam for the deck battens, which are coming up soon.

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