One day, my wife said she wanted a canoe to paddle around in the pond
outside of our house. We looked into it and not only are canoes
expensive (even used), they're very large and awkward to transport. So
we thought about a rowboat, but again - expensive! So naturally since
we couldn't find something to suit our needs, we decided to build one
that was exactly what we wanted. To the left is a picture of the
finished project as a teaser for the post.
For our boat, I wanted something that was big enough for me, my wife, and our dog as or a couple kids or other guests. I also wanted the boat to come apart for easy transport. After deciding what things I wanted, I scoured the internet for ideas, plans, and recommendations. There was a ton of information about boat building but of course nothing exactly about what I wanted so the plan for this boat and the techniques used to build it are a combination of the best and most suitable that I could find. This project was in the planning stages for a long time because I wanted to make sure that I did it right and used the best methods possible. I also wanted the boat to float :) Here are some designs that inspired me:
http://www.portableboatplans.com/duet.php and
http://www.portableboatplans.com/trifecta.php
I only found 2 interesting plans for boats that came apart and I studied them for how they worked. The concept is simple. There are basically two boats, completely sealed that are bolted together above the waterline. The point of connection appeared to be susceptible to a lot of potential stress so I decided to use heavier material and more bolts more my design. For the shape of the boat I wanted it to look like a rowboat but with higher sides and a more aggressive look with the sharp bow line. For the dimensions I found a plan that was most similar to my ideas and used proportions to calculate what the best length and width should be (thanks algebra). This website was very useful when looking at designs:
http://www.portableboatplans.com/ I didn't take many pictures during this stage of the process, sorry!
As far as the technique used for actually constructing the boat, I used the popular "stitch and glue" process. This is well described on the internet and consists of cutting the pieces of wood out for the boat and "sewing" them together in the shape that you want, then sealing them together with epoxy. This technique is very forgiving and allows the builder to produce almost any shape. It was fun to do. Chesapeake Light Craft has youtube videos of the process that I found extremely helpful. The videos show how to build a kayak, but the process is the same for boats. Click the link for more info:
http://www.clcboats.com/ Here is another description of how another guy does it with wood glue:
http://www.portableboatplans.com/resources/T%26G2%20PROCESS.pdf
So, above is basically all the information one needs to build a boat like this. You can use plans that you find online, or you can use them for inspiration and create something of your own. I chose to use these sources for inspiration and tailor the design to what I wanted. Now I'll go through the step-by step process of what I did for my boat. First, I drew out the plans that I created from dimensions that I liked and modified from other plans. After that I decided what type of wood I needed for each area of the boat. I knew I needed the bulkheads (where the two pieces connect) to be strong, so decided to use 3/4" plywood for that. I also did the same for the transom (back of the boat) so that one day if I wanted to add a motor, it would be strong enough. The walls are a thin 1/4" plywood and the floor of the hull is a little thicker at 1/2" or so. This was so I feel better about it taking a beating and not punching a hole through. You can really see the difference in the thickness of the wood in the picture above. These three pieces of plywood are one of the most expensive things used for the construction of the boat. Looking back, Im glad I used the sizes that I used.
After I got the plywood (regular construction plywood from home depot) I drew out the pieces that I needed and cut them out with a circular saw and jig saw. Then, to make the holes line up properly for the stitching process I stacked adjacent pieces and drilled holes all the way through at about 6 inch intervals. After doing this with all of the pieces I began stitching with zip ties. CLC uses wire, but I felt like zip ties were sufficient and looking back, I think they were just fine. The two images above show the boat stitched together with zip ties. This is where the boat truly begins to take shape. Some of the curves will stress the zip ties. If you feel like it will break, use a thicker one or drill more holes to distribute the force over more area. The hardest part was putting the deck on the bow of the boat. It required me to stretch the hull apart very far - I thought I would break the plywood. If you click the image and zoom in, you can see that I used heavy bailing wire to make sure it stayed. There's no way a zip tie would've held that amount of tension. Since it was so tenuous, I made some small blocks that I glued and screwed to the walls of the hull and to the underside of the deck to make sure it was secure. This is best seen in the pictures of the mast mount in a later post. This piece is crucial because it gives the bow its characteristic boat shape. If its not the right shape the bow line will look straight and awkward. The process up to this point shouldn't take longer than a day or so.
After everything was sewn and stable, I bought some polyester fiberglass resin epoxy and began the "gluing" process. For the initial glue job, its important to thicken the epoxy with some wood flour. I thought it was dumb that I needed to buy what was basically sawdust, especially when I had been sweeping it up off my garage floor for about 2 weeks at this point so I used some old sawdust and a coffee grinder to achieve my own version of wood flour and it worked fine. Working in small batches, I mixed up some epoxy and wood flour until I achieved a peanut butter consistency. Then with a spoon I applied it to the inside joints of the boat, making sure to NOT cover all the holes and zip ties. I also took care to smooth down the epoxy as I went for a more finished look. This process also should not take longer than a day or so to do a couple seams, let dry, then stand the boat up, and do some more seams. Here is a picture of the inside of the seam with the peanut butter thickened epoxy.
When all that was dry, I used a wire cutter to remove the zip ties. Once that was all done, I covered the holes and gaps with epoxy, completely sealing the boat. After that I proceeded to sand the outer seams of the boat in preparation to lay down some fiberglass. I decided to use actual fiberglass cloth do this over drywall tape (suggested by some) to reinforce the seams thinking it would be stronger. While that may be the case, it is extremely annoying to deal with. You have to cut it into thin strips and lay it perfectly flat over curved surfaces. Then while painting, all the tiny fibers gunk together an make these fiber glass balls that stick to everything. I eventually gave up trying to keep them off the boat and just knocked them off after they dried. One solution would be to fiberglass the entire boat, but that was not in the budget. I ran out of fiberglass cloth and decided to use drywall tape which I had laying around for the rest of the seams. It was easier to use and after a couple coats, you cant even tell there is something over the seams, unlike the fiberglass cloth which you can still see on my boat. I probably would just use that next time and save myself the headache. Here is a picture of the outside seam with the fiberglass cloth.
After the outer seams are finished drying, you have a boat! At this point it would probably float for awhile, maybe even for a few trips out onto the water. But plywood is extremely susceptible to moisture and would delaminate as is. To protect the hull and completely waterproof it, you need to epoxy the exterior. Before that I sanded the entire exterior for a few hours (seemed like days). Then I painted on about 2-3 coats of the same epoxy (not thickened) to the outside of the hull. Some people use fancy squeegees but I thought a cheap paint brush worked fine. Its important to work in small batches again so the epoxy doesn't harden in the cup while you're using it. Also, its important to paint over your "wet edge" and finish the whole coat in one go so the epoxy dries together. Sand lightly between coats. Here is a picture of the outer hull sealed with epoxy.
After that, the rest is basically just adding finishing touches. The next thing is to add the rub rails (or gunwhales). This component was one of the harder parts of the build, which I'll get to in a second. For the rub rails, I used 1x2 lumber. To start, I used a hacksaw to cut about half way through the piece of wood every 6 inches along its length. This helps to allow the wood to bend around the curve of the boat. After that I ran some glue across the entire length of the rub rail and clamped it to the middle portion of the boat (near the bulkheads, also this is for the aft section of the boat). Here is the hard part, I used more clamps to sequentially bend and secure the rub rail on to the hull of the boat. Sounds easy, but bending that piece of wood is NOT easy, especially if you're working by yourself. To make life a little easier when bending, I mounted the entire 8 foot piece making sure the piece was flush to the bulkhead when starting, and used the rest of the piece of wood as a giant lever. For the bow section rub rails, I cut the angles I needed to make a nice point on the bow of the boat and then mounted that first to make sure the bow looked nice. After a few clamps were on, I used screws to secure the rub rail since the clamps weren't quite strong enough to keep the rub rail tightly secured. I cut the remaining lengths of the 1x2 with a jigsaw.
For the benches, I decided to mount them about 10 inches off the bottom of the boat. This height seemed reasonably comfortable without being to high in consideration for the boat's center of gravity. I wanted them to be removable so I could use the boat to haul things or have extra space. To accomplish that I mounted some rails along the inside of the boat that the bench sets on top of. These rails are pieces of 2x2 that secured with wood glue and screws from the outside of the boat. After I got all the screws in, I painted over them with another layer of epoxy. The benches themselves are the same material as the rub rails secured with screws.
The next part of the design was to add something to protect the bottom of the boat while scooting it around on the ground. For this I simply screwed more 1x2 to the bottom of the boat in a parallel fashion. I think in hindsight, these actually help the boat's hydrodynamics since the bottom is so flat. As with the bench rails, I used epoxy over these screws as well. The last step before painting was to finish off the corners with some cabinet trim. I simply nailed it on with some finishing nails, and then used more epoxy over portions that would be submerged or near the water line. I also used a small amount of wood putty to fill smaller gaps on the deck of the boat.
Here are some final pictures after a nice paint job with acrylic paint. I also built small dolly out of PVC to move the boat around when its assembled.
