| re two general modern techniques for building plywood | | | | drilled into adjacent panels close to the edge and either |
| boats at home: the traditional, Ply on Frame | | | | copper wire or nylon tie-wraps are threaded through |
| construction and the newer Stitch and Glue method. | | | | the holes to stitch the plywood edges together. |
| Each has its advantages and disadvantages. Both | | | | Then an epoxy mixture thickened with silica or |
| methods of boat construction are capable of | | | | microspheres is puttied into the joint to make a fillet |
| producing very functional, strong, and safe vessels. | | | | and the joint is taped over with fiberglass tape. The hull |
| Which boat construction method a potential boat | | | | is flipped over and similar joints are made on the |
| builder should select, depends as much on the skills, | | | | outside of the hull. Then, if desired, the hull is |
| patience, and preferences of the builder as on the | | | | fiberglassed. |
| desired characteristics of the finished boat. | | | | Contrary to first impressions, a stitch and glue boat, if |
| Let’s begin by discussing the traditional ply on | | | | properly designed and built, is just as strong and |
| frame construction method. It's done by starting with | | | | capable as its framed counterpart. They’re |
| wooden frames, sometimes called ribs. These are | | | | simply different philosophies in construction. Just as |
| usually straight sided, however some older designs try | | | | cars and aircraft have changed from framed and |
| to incorporate curves in the rib elements, complicating | | | | covered construction to more modern, unibody in the |
| the construction considerably. These frames are | | | | case of cars, and monocoque in the case of aircraft, |
| positioned using a construction jig, generally oriented so | | | | construction, so naval architects have been |
| that the hull is built upside down. | | | | transitioning from framed to stitch and glue |
| Longitudinal frame members are attached into notched | | | | construction for light, strong, easy to build boats. |
| slots in the ribs. The first one is a heavy frame | | | | Now that you know how these boats are built, |
| element called the keelson that runs down the center | | | | let’s talk about what kinds of skills and |
| of the ribs. To the forward end of this element, the | | | | personality the builder has, in order to select the right |
| vertical timber that forms the prow of the boat is | | | | kind of boat for him. First let’s look at |
| attached, called the stem. | | | | woodworking skills. Do you like to work with wood? |
| Two longitudinal frame elements run along the upper | | | | Does planing on a nice piece of hardwood bring you |
| edges of the hull, one on each side, called sheer | | | | joy? Do you like the smell, the feel and derive |
| clamps. Two more elements are added the bend of | | | | satisfaction from shaping wood? Don’t laugh. |
| the ribs where the hull bottom transitions to the hull | | | | This is a serious question. Some people will say, yes, |
| sides. This joint in the hull is called the chine and the | | | | that’s me. I love it! Some will say, no, not really. I |
| frame member installed here is called the chine log. | | | | see it as a means to an end and I just want to get |
| Depending on the size of the hull and the | | | | done. |
| designer’s philosophy, sometimes, additional | | | | If you’re in the first group, loving to work wood, |
| longitudinal members may be specified to complete the | | | | you probably have what it takes to make a framed |
| boat hull framing. | | | | boat. It requires woodworking and being careful about |
| Most often each of these joints are glued and | | | | joint fits. It requires some patience and a sense of |
| screwed or in somtimes, bolted together. These days, | | | | pride in your workmanship. |
| high strength synthetic adhesives, such as epoxy or | | | | If you’re in the second group, you probably |
| the new polyurethane adhesives make an excellent | | | | should build a stitch and glue boat. They go together |
| for bonded joints because unlike the older natural, | | | | much faster with fewer steps. They also require less |
| casein, or polyvinyl acetate glues, the modern glues will | | | | woodworking knowledge and use of tools. You still |
| still hold even if the joints aren’t perfectly | | | | have to be able to cut out plywood fairly precisely, but |
| matched. They fill gaps better. | | | | almost everything can be done with simple power |
| Next the plywood planking is leaned against the | | | | tools. |
| framework, cut a bit oversized, glued and nailed (or | | | | Building a stitch and glue boat is a messier proposition |
| screwed in-place) and trimmed to the edges of the | | | | than a ply on frame hull. You have to mix and spread |
| framing. Finally the plywood is finished off with one or | | | | lots of epoxy, usually wearing rubber gloves, If you |
| more layers of fiberglass, or simply saturated in epoxy | | | | scratch your nose, you’re going to have to |
| to improve strength, abrasion resistance, and water | | | | spend some unpleasant time with acetone getting the |
| incursion. | | | | epoxy off too. Working with wood, you just dust |
| Stitch and glue boats, on the other hand are built in an | | | | yourself off most days. There are adhesives used, but |
| entirely different manner. These boats are built using | | | | not to the extent of a stitch and glue boat. |
| precisely cut panels that will end up forming the shape | | | | When you sand epoxy, you should wear a respirator |
| of the hull. There is no internal framing, or if there is, it | | | | to prevent epoxy and fiberglass dust from getting into |
| takes the form of bulkheads rather than frame | | | | your lungs. Sawdust isn’t as damaging to your |
| elements. The builder uses either full sized panel | | | | system, but I still do wear a respirator when sanding |
| drawings supplied by the designer, or lays out the | | | | large expanses of wood with a power sander. |
| finished shape of the sides and bottom of the hull on | | | | Well, I hope this has helped you decide which of the |
| the plywood planking. The planking is then cut out. One | | | | two types of hulls to build. I would strongly encourage |
| side may be used as a pattern for the other, because | | | | everyone to build a boat. It’s a fun hobby and a |
| getting both sides precisely the same shape and | | | | great experience. It’s also the parent and child |
| keeping the bottom very symmetrical are important. | | | | project. |
| Once the panels are cut out a row of small holes is | | | | |