Birdwatcher-2 Building the Afterdeck
Birdwatcher-2 Sailboat, designed by Phil Bolger
The Birdwatcher-2 (BW-2) has an aft deck that primarily accomodates the 2-HP Honda outboard, but also provides an outside area to store and use items that might be best not inside. This page shows the deck, the lockers beneath the deck and some details of the motor mount.
Before installing the afterdeck, the flotation foam was installed. Two-part expanding foam was poured into all voids. The boards clamped to the hull and the level are part of finding the proper place to cut the hull for the motor mount.
The foam easily sands to its final shape. It is 8-inches high and covered with 1/4-inch plywood. This shot also shows the gutter that was added at the forward edge of the wet locker. This is primarily to carry water under a dry locker that occupies the starboard side under the motor cutout.
While everything was in the open, I mocked up the steering lines and their cheek blocks. I chose to run both lines on the port side to give a little more room for the motor.I tried to be careful that the two turnbuckles would not hit together on the two lines.
The afterdeck is wider than a sheet of plywood, but can be formed from a single sheet by cutting diagonally and joining the two halves. This is seen here before cutting. This all works since the afterdeck tapers down in width going aft. The ability to have the boat pieces fit the plywood keeps re-appearing as the project continues. Thanks, Mr. Bolger!
Here is the deck after joining, but upside-down. I left a supporting bridge by the cutout for the one vertical support. This was removed after the afterdeck was installed on the boat. Also, there is a vertical longitudinal support divider under the afterdeck. In order to not join the deck halves on top of this divider, I sliced the two halves about a half inch off of center with the larger piece on the port side. This leaves adequate room for a fillet connecting the deck to the divider.
Here the after deck has been installed. The deck doubler is an extra inch thickness of plywood forward of frame D. This gives support for the window framing and for stepping onto the afterdeck. You can also see the cutout for the wet locker on the port side and almost see the access hole for the dry locker, a rectangular hole below the deck doubler.
Most of the detail work is done for the afterdeck. The slot in the middle is for the fold-up rudder. It also allows easy removal of the pintle rod. The hatch to the wet locker on the port side has coamings to keep water out. Four drain holes have been drilled down through the deck to dispose of water after the polycarbonate is added on the sides. I put a bit of camber in the after deck, mainly to avoid the reverse effect of a of dip in the middle. The edges are 1/4 to 1/2 inch lower than the center.
You are looking up at the bottom of the after deck on the starboard side. I was concerned about the strength of this part of the boat. On the starboard side, the motor cutout reduces the opportunity for bracing. It is attached to the hull right at the aft end, but this is not strong. The diagonal plywood piece helps much to strengthen the deck around the rudder cutout. The longitudinal members along the outer edge are quite strong for holding the corners.
The port side is easier, not having the motor cutout. I still added a 1-1/2 inch wide piece of 1/2-inch plywood to reduce flexing at the end of the hull. It overlaps the bracing along the edges of the rudder cutout. This is the view looking forward under the after deck.
Info on Motor Mounting and Cutout
Back to Building Birdwatcher-2 main page
This was last revised 26 November 2005. Bob Larkin, Corvallis, Oregon