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Laker 14 Tunnel Boat Plans
Page Eight
Upper Sides, Deck & Flotation

The general rule is one cubic foot of flotation will support 60 lbs. Figure about 285 lbs. of motor, plus 35 lbs. for the battery. We'll assume the boat's hardware is offset by the bouyancy of the wooden hull. You still need more than 5 cubic feet of flotation.

It is worth noting that for an SST60 boat, a boat the same size as the Laker 14, APBA rules require 5.5 cu. ft. of flotation.

If you fill the space within the sponsons between bulkheads three and four, you should be right about at 5 cubic feet. An additional cubic foot elsewhere in the boat should be adequate.

I used high-density foam board for the Laker. I loaded the foam into the hull before installing the upper sides.

The other option is two-part pour foam. For this you will want to install the upper sides first (see below) to help contain the foam.

Line the space with plastic sheeting. I have discovered, to my shagrin, that pour foam shrinks some after it cures. If it is poured directly into the hull it will grip the plywood and lumber with enough tenacity to distort your hull as it shrinks.

Also, make certain that bilgewater can drain past the foam and does not get trapped in the forward area of your sponsons.

Installing the upper sides is straightforward. Again, the joint can be scarfed or butt blocked.

The inner and outer decking meet at the tunnel side. The inner deck, which is installed first, extends from the carlin to the inner-most deck stringer, but does not overlap the edge of the tunnel side.


... over the tunnel extension where a little extra plywood is needed.

Forward of station three, the two parts of the deck diverge, the inner deck descending to the bow beam.

Although the edge of the inner deck is straight, the edge of outer deck is gently curved where the two meet.

Use a block plane, sanding block or belt sander to bevel the edge of the outer deck. Perfection is not required. Any gaps can be readily filled with epoxy sanding filler.

The outer deck completed. As with all other plywood joints on this project, scarfs or butt blocks are used.

As mentioned before, you may choose to install the deck first then the coaming, or the other way around. I installed the deck first so that the plywood could be neatly trimmed along the carlin for a nice tight joint with the coaming.

NOTE: I left the starboard (right side) outer deck unistalled at this time, pending installation of the "Teleflex" steering cable used on my Laker.

See Page Eleven for more on that.

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