Illustrated Guide to Building a Spira International Ply on Frame Boat Spira International, Inc. Huntington Beach, California Copyright, 2008 All Rights Expressly Reserved
Building a Spira International Ply-On-Frame Boat The unique Spira International Ply-On-Frame boat designs are perhaps the easiest to build of the traditional, wood framed, plywood planked boat designs available today. They are alsoa reliable, seaworthy small boats able to handle most lake and near coastal conditions. Of course, there's no substitute for common sense and anyone contemplating taking one of these boat out in any rough water should be thoroughly familiar with small boat handling in poor weather conditions. To build the boat, you should also be familiar with using wood working hand tools and hand-type power tool such as saber saws, electric drills, and electric sanders. You could build this boat using only hand tools but power tools sure makes the construction go much faster. I personally find the time savings using power tools allows me to do a better job. For instance, if Iset out to sand a boat, I get bored in a few hours and if I'm hand sanding, I won't have made nearly as much progress by hand than if I'm using a power sander, so I ll generally do a much better job if using a power sander than the good enough attitude after my hand gets sore wnen hand sanding. In any case, if you have spent sometime using wood working tools, you'll have no trouble building these boats. If this is your firstendeavor into any kind of wood working, I'd suggest building a tune up project of some type before building the boat. One great idea is to build a pair of saw horses. You'll need them to build the boat and it will give you a chance to get used to the tools. Tools To build a ply on frame boat, following is a list of suggested tools you'll need. This can be considered a minimum list. Power Tools Saber Saw Electric Drill Power Sander (random orbital) Electric Screwdriver Hand Tools Block Plane Screwdrivers (both straight & phillips) 20 (or more) 2" or 3" "C" clamps Hammer 3/4" or 1" Woodworking Chisel Wrenches for the bolts. Plenty of clamps always come in handy when boat building Materials Standard construction grade materials are called out on the boat building plans. You may upgrade materials, of course, but it is not necessary to use expensive marine grade products, especially not if you re planning to fiberglass cover the hull. The materials called out are common in the Western United States and your area may not have the exact materials. You may substitute with the local equivalent. If you are not sure if your local materials are OK, drop me an e-mail and I ll check them out for you.
Building Procedure Building a wooden framed boat is best accomplished on a strongback. Generally this is made of a strong wooden beam just long enough to fit inside the boat. This brings the boat up to a omfortable working height and keeps everything aligned while the boat is under construction. On some of the boat designs the strongback is detailed and on others it s left up to you. This is usually dependent on how complex the strongback needs to be. If a smaller boat, it s usually quite simple to construct. Strongback Jig Traditionally, the frames of the boat are built first. Using the plans, lay out the frames full size on a piece of plywood (some cover it with butcher paper so it is fresh for each frame). The wood frame members are then cut and laid out on the pattern, then drilled, glued with epoxy, andbolted together to form the shapes as shown on the drawings.
Next, you need to set the ribs on the strongback.. On some boats like the Carolina dories, or some of the Grand Banks dories, the bottoms are straight, so there s no need to block up the frames. Just tack them to the strongback in their correct longitudinal locations. Still other boats, like many of the vee bottom hulls, have the strongback designed so that you do not need to worry about heights. But on many boats, you will need to raise the ribs up from the strongback to create rocker or a curve to the bottom. Temporary simple blocks may be used, or more complex, notched blocks can be created to create this curve. Blocking Up Frames The keelson is next to be attached. Drill through the frames and keelson and bolt frames in place using epoxy glue as shown in the drawing. Pay close attention to whether the frame risers are toward the forward or aft side of the frame bottoms.
After the frames are in place, add the stem and any stem knee (filler between stem and keelson) that is called out on the drawings. Rough shape the joint where the keelson and stem come together keelson with a saber or band saw. Epoxy it and bolt it into place as shown. Build up the transom and cover the outside with plywood. The aft end of the keelson should be beveled to a 12 degree angle so the transom aligns properly once it is located. Drill starter holes, epoxy the joint and attach it in-place to the end of the keelson using the lag screws. The chine log comes next. You must cut out notches in the frames as shown on the drawings. Drill through the log and frames. Using epoxy as a glue bolt the joints together. You'll find it's easiest to begin at the transom and work forward going from one side to the other. This minimizes the tendency to warp. As you approach the keelson stem area, you must cut away the material to smoothly transition to the bow. Fitting the Chine Log Repeat the process used for the chine log for the two shear clamps. Once the framing is complete, the next step is to "fair" the boat. This involves planing the frames and chine log so that plywood will smoothly fit on the outside of the boat. Take your time doing this so the fits are tight and smooth. Some people (and I include myself) like a drawknife for this work, but be careful, it takes some practice to keep from removing too much material.
After all the framing is faired, roughly cut out the plywood planking a bit oversized. Mix up a batch of epoxy, apply it to the area you're planning to plank and clamp the plywood in-place. You then can now fasten the plywood using either boat nails or better yet, drill and drive stainless steel screws with about 3-4" spacing along the frames and about 6" spacing along the chine log or shear clamp. Again, it is best to work from side to side to minimize the tendency to warp the boat. Apply the side planking first, then plane the edge smooth along the bottom, so that the bottom planking covers the edge. Apply the fiberglass tape with epoxy along the plywood seams. You may optionally cover thebottom or the whole boat with one or more layers of fiberglass for a long lasting, tough finish. At a minimum, sand and saturate the wood with epoxy before turning over. Fiberglass covering is optional on most Spira International boats, and is recommended
Flip the hull over. Epoxy the plywood joint butt blocks in-place on the inside of the hull everywhere you find a joint. Run a few screws to hold the butt block in-place while the epoxy hardens. Saturate the inside of the hull with epoxy also. Don t forget to saturate the inside of the hull with epoxy. Not it s time for a good coat of paint, or you might elect to varnish your boat with either traditional spar varnish or the new polyurethane varnishes for that beautiful wood look. Your hull is now complete. The fitting out of seats and accessories up to you you from