Orca, The

Radio Control Boat Modeler, Jun 2003 by Tritle, Pat

CONSTRUCTION

The first time I saw the movie "Jaws," I knew that one day, I would build an RC model of the "Orca" fishing boat. As usual, weeks turned into years and the model never got built. I recently saw the movie again, though, and decided that I had waited long enough. Besides, I wanted something to enter in the RC Boat Modeler Design Contest.

Fishing boat from "Jaws"!

It didn't take me long to realize that scale 3-view drawings probably didn't exist, and this was later confirmed by a television documentary that I saw on the making of "Jaws." It turned out that the boat had been purchased locally during the movie's filming and was modified to suit the producers' needs. The problem of how to obtain reference material was resolved when a modeler friend suggested that I use a software program called "Snappy" to copy images directly from the video and print them out as needed. After carefully scrutinizing the film, we printed about a dozen images to use to work out the proportions of the boat and to add detail. During the design and building phases, I watched the pertinent scenes several times to pick up on subtleties that we missed in the still images. Every time I watched the movie, I noticed something new!

I estimated the Orca's hull to be about 35 feet long. I wanted my model's hull to be no more than 30 inches long, and that made the model approximately 1:14 scale. Adding the pulpit brought the overall length to 35 inches. Though I had originally planned to use a direct-drive power system, I later decided to go with a Dumas 6V high-speed motor with a Master Airscrew 3.5:1 gear reduction and a Hitec 10A ESC with reverse. I had been running another boat using this system, and it worked so well that I thought it might be just right for the Orca, too.

The Orca looks a lot more complex than it really is, so a little study now will save a lot of confusion later. For the sake of simplicity, I decided that balsa and lite-ply would serve well for the hull construction. I also used balsa and a bit of hardwood in the appropriate places for the upper decks. I added details with brass wire and whatever else looked as though it would work. To become familiar with the construction style, study the plans and construction sequence before you begin to build.

BUILDING THE ORCA

Begin hull construction by cutting the keel and hull frames from 1/8-inch lite-ply and 1/8 balsa as shown. To assemble the keel, mark the prop-shaft location on both K-4 pieces, and make a relief to allow the stuffing box to pass through the assembled keel. Glue the keel together with the stuffing box in place. Locate and glue the 1/4-inch-square balsa deck and battery-tray supports to frames H-3, H-4 and H-6. Glue all the frames to the keel followed by the chines and shears (three laminations of 1/16x3/16inch balsa) and the deck rail (1/x3/16-inch balsa). Pin the basic hull structure to the building board using appropriate shims to keep it nice and straight. Plank the hull bottom starting at the bow. Using 1/8x1/2-inch balsa (running beamwise), plank from the keel to the chine from frame H-1 forward. From H-1 aft, use 1/8x3/4-inch balsa, running lengthwise all the way back to the transom. Plank the hull sides lengthwise using 1/8x3/4inch balsa. Rough-sand the hull to shape, and remove it from the board. Add the outer deck from the deck rails outward and from H-1 forward using 3/32-inch balsa. Last, add the battery-tray assembly at frame H-3 and the mast socket assembly aft of H-4.

Begin the cabin construction by cutting the forward and aft lower cabin sides from 1/8-inch balsa. Use the aft lower cabinside pattern drawing to build the side window frame. (Note the vertical-grain direction on the forward section.) Fit the cabin sides and glue them into place. Fit and glue into place the 'A-inch balsa fore and aft crosspieces at frames H-1 and H-6, followed by the 1/8-inch balsa headers atop frames H-2 and H-3. Fit and glue the 3/32-inch balsa upper foredeck into place. Cut the forward splash rails from 1/32 ply, fit them into place so they're flush with the outside of the hull planking, and glue them into place. Cap the splash rail with 1/16x1/8-inch balsa, build and fit into place the windshield frames and glue them to complete the basic structure.

Using the detailed assembly drawings, build the battery hatch, lower cabin, flying bridge, aft deck and servohatch-cover assemblies. The main cabin roof will be glued to the aft cabin wall, and the flying bridge will be glued to the cabin roof, but that assembly will be removable from the completed model, as are the battery hatch and the rear servo hatch.

SEALING AND PAINTING

To prep the structure for paint, I brushed six coats of Varathane varnish on the hull and decks, then I sanded it lightly between coats to remove the balsa "fuzz." I primed the structure with Du Pont acrylic filler primer and sanded it lightly.

Though the Orca must be built to be seaworthy, don't get carried away with making its surfaces look too good; the original Orca can be described only as "a mess"! Bumps, bruises and uneven planks were obvious everywhere on the full-size boat, and to accurately reproduce that look, you don't want to overdo it with the sanding block. This is one time that it's OK to "quit before you're finished."