Steam Launch - Boat Build

The same process was used to create a all the ribs and bulkheads. Most were cut from 6mm plywood but 12mm was used for rib 7 which would form the transition between the Vee part of the hull and the flatter section over the propeller and rudder.
A thicker wood was used for the stern plate too (rib 10).

Each rib had a chine notch cut into it. The chosen chine material was 9mm square section pine.
The cut-outs in each rib were made lightly shallower than 9mm so that after sanding the chine would form a smooth transition between the bottom and sides of the hull.
Each rib also had a cut out made at the bottom to suit the keel.

The rear stern plate, rib 7 and rib 1 were glued and nailed to the keel first.
Then the keel was place upside down on the deck panel and all the remaining ribs were glued in place.
Note that the keel was left proud of the ribs so that after sanding it would provide a flush fit.

Once the glue on the basic frame was dry, the chines were added.
These parts were pinned and clamped in place to help them hold their correct position whilst the glue set.

The whole hull was sanded using sand paper on a block; so that the keel and chines formed a smooth transition to the ribs.
A straight edge was used to check for the correct angle along each rib.
The nose of the keel was also sanded to a point.

Before the hull was planked the steam plant was positioned in the hull and the propeller shaft was offered up to mark the location of the required hole. The chosen propeller shaft was 7" long.
The angle of the shaft should be minimised, by tilting the engine if needed.
The hole was drilled oversize so that final alignment could be set later and the shaft held in place with epoxy glue.

The sides of the hull were planked first. Each planking strip was glued clamped and pinned as necessary to get the plank to follow the profile given by the frame.
The planking material was 1.5mm modeling plywood.

Each planking panel was cut oversize and then trimmed once the glue had set. Trimming was done with a craft knife and then sanding was used before fitting the next panel to ensure a flush fit.

After applying some coats of gloss paint to the inside and outside of the hull, an engine room floor was cut from 9mm plywood. This floor was shaped to sit between the ribs and was long enough to support the burner tray when extracted from the firebox.

A cover plate, modelled around the steam plant, was cut from 6mm plywood and shaped to match the hull.

The rudder was a brass plate soldered to a 4mm rod which was housed in a brass tube glued to the hull.

At the back of the boat a servo and rudder linkage was devised to control the rudder.
Also in the electronics compartment were the radio receiver, batteries and an on/off switch.
Also a water alarm made from a Velleman kit which would sound an audible warning if water started getting into the hull.

The superstructure was made from plywood offcuts, sanded and shaped to resemble a sporty looking fast launch.

A mixture of gloss blue and black paint was used combined with some sticky trimlines for detailing.
Metal plates were added to the bow and stern to allow the magnetic hook on the electric rescue boat to connect with the steam launch, if needed.

The cabin roof had to be notched for the smoke stack and the inside was fitted with a stainless steel heat shield.

The top superstructure was secured to the hull with three thumbscrews, machined to look like marine bollards.

The finished boat.