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Mini Tunnel (Redesigned Version) Boat Plans
Page Six
Deck Stringers

Invite a friend or two, turn the boat over, celebrate with an appropriate (or inappropriate) beverage, then shoo everyone out the door and let's get back to work.

Start by completing the framing of the tunnel extension (where the tunnel plank extends aft of the transom).

The cleat shown is 3/4 inch wide and is as tall as, and cut at an angle to match, the upper edge of the tunnel side.

This photo is from the Pro Tunnel; your Mini Tunnel will look a little different, for instance your tunnel battens probably don't extend aft of the transom beam.

There are two stringers that run along the top edge of the tunnel sides.

The inboard stringer is set flush with the top edge of the tunnel side from the tunnel extension to bulkhead three where it begins to dip below the edge and descends to the bow beam.

The outboard stringer follows the edge of the tunnel side for its entire length, from the transom to the sponson tip.

The outer deck battens also extend from transom to sponson tip.

Bend on the outer deck stringers.

Ideally, the inner deck battens (not seen in this photo) would land on the bow beam midway between the carlin and the deck stringer. But the exact placement is not critical.

The carlins undergo a fairly severe compound bend from bulkhead three to the bow beam, with particular stress experienced at bulkhead two.

I secured the carlin in its notch at bulkhead two with a 12" bar clamp. As soon as they were glued in place, I added glue blocks, cut at the proper angle, to both the fore and aft faces of the bulkhead.

Furthermore, I added a scrap of deck stringer glued to the underside of the carlin and the deck stringer, just to make sure it was secure.

I left the clamps in place for a couple of days to make sure the glue was fully cured.

A second layer of plywood is added to the extension of the tunnel side.

The completed tunnel extensions should be provided with a drain holes. Although this area will theoretically be sealed and water won't be able to get in, better not to depend on that and add the drain holes.

I initially drilled a 9/16" hole which I filled with thickened epoxy, then re-drilled to its final 3/8" size.

For the sponson drain, initial hole was 1" and the final is 5/8".

This method provides a neatly drilled drain that completly protects the wood it is bored through.

Now might a good time to seal the interior surfaces of your hull. Epoxy is always a good choice. Spar varnish, exterior grade polyethane varnish or exterior grade paint will also do the job.

Pay particular attention to the area just inside the drain holes where that last little bit of water will always remain until it can evaporate away.

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