Boat Building

Between September of 2005 and February of 2006, I re-activated my boat shop to build a new radio controlled boat. Using lines found in Howard Chapelle's boatbuilding book for a 35 foot Utility Launch, the boat was scratch-built with the intent of using extra wood left over from previous projects. Because of the left-over nature of the materials, the whole boat set me back less than $100. Here are some highlights of the process of scratchbuilding a boat from lines drawing to completion.

Step 1 is to draw out the parts and start cutting. Here's a partial photo of the various parts drawn out full sized (called lofting). Then the shapes were transferred to 1/8 inch plywood and cut using a band saw (those are the light tan pieces). The dark wood keel pieces are solid walnut, left over from a box-building project my father started. The lofting itself was drawn by hand from the measurements given on the plans for the full sized boat, and scaled down.

Making the keel took three separate parts. In the bow, I simply didn't have a wide enough piece of wood to cut it as one piece. In the stern, pictured here, the propeller and rudder had to pass through the keel. In a normal boat, this would be drilled out, but since the shaft was almost the same width as the keel material, I drew in the width of the shaft housings onto the pattern for the keel parts before cutting these parts. Then I epoxied the tubes that surrounded the shafts into the keel. To maintain the color of the dark wood, I mixed in walnut sawdust saved from sawing the keel and mixed it into the epoxy.

One together, I cut slots into the keel for the frames to fit into. Sometimes things don't quite work as planned. This is frame #8 that's sitting too low on the keel (remember the boat is upside-down here).

In this photo, notice the extensions glued to each of the frames. This was how I maintained proper hull alignment without a secondary structure like a strongback. With everything lined up, the sheer and chine clamps are installed into their frame notches. Here's the frame completed and ready for planking.

The balsa wood sub-planking is now completed. You can just see the herringbone pattern to the bottom planking that was called for by Chapelle's plans. The advantage to this was ease in planking, since the angle of the herringbone compensated for the curve in the bottom.

Here the final mahogany planking for the bottom is complete and the sides are started. The mahogany is 1/32 inch veneer, used for facing cabinets. I'm using fast-set "super" glue to attach it to the balsa. Note: if you try this method of planking (and if I try it again) start at the middle of the boat and out out towards both ends. Planking from the bow back introduced a fairly severe upwards curve by the time the planking reached the middle of the boat. This could also prevented by "spiling" the planks (varying their width), but that's a skill I'm still learning.

Here's a detail of the hull contruction. Looking outboard of the last frame, you'll see two 1/8 square lengths of basswood that are the sheer, the 1/16 inch balsa base planking, then the 1/32 mahogany outer planking. This is similair to how real-life mahogany runabouts were built and actually makes for quite a strong boat.

This boat is roughly 30 inches long, but it doesn't have a lot of interior space so all the control electronics had to fit into the deckhouse. The red box on the right is the motor speed controller, and the male and female plugs are the connection between the battery and the motor controller. The empty battery holder is for lights, along with the switch, screws and loose wires. The twisted red and black wires are for the controller's on/off switch. The radio receiver is mounted on the underside of this tray, towards the rear. At the extreme left are the heavy gauge wires that carry electricity forward from the main battery and aft from the motor controller to the motor.

This is the deckhouse nearly completed. Note the heavy wires that carry the electricity from the battery mounted in the stern to the speed controller and then back to the engine, which is mounted amidships. In addition to the working door, the upper hatch slides on rails to allow access to the batteries and switchs.

This photo was taken slightly earlier than the previous shot and shows the center of the boat. You can just see the lower corner of the main battery in the background and the string that boxes the engine is part of the steering system. The control is the vertical stick on the left, which is connected to the rudder via four blocks (pulleys to you landlubbers). This is the system that is shown on the plans for this craft and it works well in scale. In the forground is the framing for the aft end of the deckhouse, before the walls were planked using the same double-layer process as the hull.

One of the last big jobs was the hand carved name plate. Done in solid walnut, the shape and lettering was generated by a word processor. I used a light coat of paper glue to tack it to the wood to use at the template to starting carving from. It took several nights to cut finish it, and it turned out to be one of my favorite projects. Then the letters were painted white for contrast, and the whole thing was given several coats of marine varnish. In the picture below, the letters are painted, but the varnish hasn't been applied.

Here is the boat almost done. The deck is home-made balsa and maple plywood, and the engine cover is mahongany planked. It also shows the limited workshop that I have, due to the relatively small condo I live in. The scale flags are the Power Squadron ensign and the burgee of the San Diego Sail and Power Squadron. I happen to be a member of that organization and the Seamanship instructor, which allows me to fly them. If you're at all interesting in real boats, I can highly recommend the Power Squadron as the place to go to get involved in boating of all sorts.

Here's the completed boat. In addition to the working doors and hatch, it has working forward navigation lights, stern light and two interior lights. The project ran from September 3, 2005 to February 14, 2006 and I probably spent 8 to 9 hours per week on the project. Unlike my first projects that seemed to have one impossible problem to solve a week, this project went fairly smoothly, with only a few problems that made me think the project was doomed. Hope this inspires you to go out, build a boat and take it to the pond. Hope to see you there.