Tuesday
May242011

« 22 Foot Steam Launch Design #123

Our plan files contain several designs in the 20 to 24 ft range for hulls suitable for steam or electric power.

This 22 ft fantail steam launch was built in our shop in 2001-2002. Power is a 2¾ hp steam engine turning an 18 in. x 30 in. propeller at 350 rpm.

Construction is double planked red cedar on bent oak frames, fully glued.

Lines plan for Design #123, 22 Foot Steam LaunchBoring for the stern tube.

The backbone is laminated yellow cedar with an oak worm shoe. The shaft log was assembled with a square pilot hole. The stern tube is glass and epoxy resin laid up over a copper liner and will be bonded in place. Here the boring bar has been set up ready to open up the pilot hole to tube diameter.

 Setting up.

The hull construction is double planked red cedar on bent oak frames, to be built upside down. Here the building frame has been assembled and the temporary support structure for the beamshelves set up. The beamshelves, which are horizontal and sawn to shape, have been fitted to the curve of the sheer line. The first building mold is being set up.

Rim timber assembled and glued.

With the molds all set up, fashion pieces are fitted to the beamshelf in the stern to form the rim timber around the fantail.

Backbone fitted and fastened.

The backbone has been lowered into place in the mold notches and fastened bow and stern. The rim timber has been dressed to shape and faired into the plank rabbet along the horn timber.

Ribbands and frames.

Ribbands notched into the molds completes the building jig. Ribbands attach to the rim timber and to the stem with jogged cleats to ensure correct alignment for the frames. The wide stringer is a permanent bilge stringer. In this picture framing has begun amidships.

Framing (July 2001)

The frames are Garry oak, 1 in. x 5/8 in. on 6 in. centres. Amidships they run in a single length from one side to the other. In way of the stem, shaft log and horn timber they are let into sockets chopped into the backbone. Here frame sockets are being chopped along the horn timber. July 2001.

Framing completed

Framing complete and faired for planking. Note frames boxed into backbone aft. Farther forward they run in a single length from sheer to sheer, with glued wedges at the garboard.

Planking in progress

Planking is two layers of red cedar laid fore and aft with seams staggered, set in epoxy glue. Fastenings are temporary screws through plywood buttons. Inner layer is 1/4" thick; the outer layer 1/2".

Planking complete

Before fairing, all holes left by fasteners are filled with pin plugs set in epoxy.

 Turning the hull over

Design #123 hull and deck package ready for delivery to Bellingham WA. Installation of machinery and finish work will be carried out by the owner. Another view of the boat ready for delivery.