Intro: Build a Boat!
Over about a six month period I built a boat. The hardest decision was to design my own or build from a set of plans that were already available. I chose the latter because there were already many, many plans available.
The plans I built from are included in the book instant boatbuilding with dynamite payson, the boat is known as the bolger cartopper. A chronological build is available on my blog.
Step 1: Materials Selection
Boats can be built from a variety of materials. Typically fiberglass, wood, steel, or aluminum. This boat was built from a combination of wood and fiberglass.
Boats built from wood usually employ exotic "marine" ply or to save on cost "exterior grade" ply wood. Since I just wanted a boat that floats and knew I would be fiber-glassing it anyway I chose a high quality 5 ply 1/4" exterior plywood available at my local lumberyard. My total cost was just under $80 for the four sheets that the bolger cartopper requires. This represents the largest materials expense in building the boat.
The rest of the boat required a small amount of douglass fir lumber, about 200 ring shank nails, 8 yards of 6oz bidirectional fiberglass cloth, 1.5 gallons of polyester resin(If i did it again I would use epoxy resin), and some electrical fence wire(for stitching panels together).
My total cost not including engine was $300
Step 2: Tools
Tools that I used:
various drill bits mostly 1/8 inch or less
Hand Power Planer(the most useful tool)
Hand Belt Sander
Table Saw(Only needed twice, borrow if possible)
Step 3: The Butt-joint
Since the 4x8 sheets of plywood aren't long enough to build a 11.5ft boat from we have to make them longer. To accomplish this I had the choice of using a scarf or a butt joint. Since the boat is so small I felt it didn't need the strength of a scarf. So I chose a butt joint. This was very simple to make.
1- cut one sheet to the dimensions on the plans (almost in half).
2- Butt the straight edge of a half sheet and full sheet together on a flat surface covered with was paper.
3-Coat both surfaces with epoxy or polyester resin
4- Lay a 4 inch wide strip of 6 oz fiberglass tape across the entire length of the butt-joint
5- Be sure the tape is completely saturated and there are no air bubbles
6- place peel ply or wax paper over butt-joint and smooth out the resin with a putty knife
7- let it dry for at least 24 hours
8- flip plywood, and repeat for the other side.
These steps will be done to create two 12ft pieces of plywood.
Step 4: Lofting Overview
I am going to go over how to loft the design first, and simply reference it throughout the rest of the instructable.
Lofting is just a game of connect the dots, and it is the first step in building most stitch and glue boats. The plans come with a sheet depicting the layout of all the plywood parts with numbers showing various points on each component. Thinking of the points like they are on an xy plane all you have to do is take the horizontal and vertical distances from the plans, measure and transfer them to the plywood. Then when each point is plotted drive a brad nail into each dot.
Now all you have to do is connect the dots. Obviously we can't use straight lines, so we will use a batten. Which is a long, thin, straight, and flexible piece of wood. Mine was about 3/8" x 3/4" x 150". Take the batten and place it against the outside of the nails. My batten was flexible enough that I was able to attach it to the brad nails with clothes pins. At this point the curve of the batten represents the shape of the panel. Use the batten as an edge to draw the curved line from one nail to the next. Be sure to double check the measurement.
Obviously if you have one available to you a shopbot would greatly improve the quality of lofting, and hopefully one will be in my shop one day to help me produce more small boats and molds for high power rockets.
Step 5: Cutting the Panels, Frames, and Transom
The plans are very detailed when it comes to laying out the panels. There are five panels, three frames, plus the transom.
1- Using the directions for lofting, loft the bottom panel, one bilge panel, and one side panel. Cut them all out then use the bilge and side panels as patterns.
2- flip the bilge and side panel onto the sheets, weight them down, and trace around them to make exact replicas. Then cut out.
3- Loft and cut out the transom
4- Loft and cut out the frames A,B,and C. However, keep the center sections in place to help with rigidity.
note: If you are anything like me the lines you cut aren't perfectly smooth, so cut just past outside of them and use your power plane or belt sander to smooth everything to the cut line.
Step 6: Stem
This is the most tedious part of the boat to build and requires several lofting steps. The stem is built from 4 layers of 1/2" plywood.
1- Loft the dimensions
2-cut out and smooth
3- make 3 identical pieces from the original
4- stack, clamp, and glue together
5- loft the lines for the rolling bevel onto each side and the front of the stem.
6- use a power plane to remove wood from each side of the stem to the two lines drawn for the rolling bevel on each side of the stem.
7- smooth bevel with hand belt sander
Note: Sand of any glue or epoxy that has squeezed out from between the plywood layers before planing the profile of the stem.
Step 7: Assembling the Pieces
At this point you have spent about 20-30 hours just getting ready to assemble the boat. Be prepared to spend about twice that finishing out the boat plus another 10 hours painting.
This is the fun part.
1- The first thing I did was make some legs That I could clamp frames b and c to.
2 Since the frames are a little thin attach 3/4" blocks to both sides with wire nails(easy to remove) and make sure they are flush with the edges of each frame a, b, and c. We will be temporarily attaching the hull panels to these block later.
3. On each panel draw the lines where each frame will be attached. Be sure to mark both sides of each panel.
4. Attach legs to panel B and C, check spacing against plans, ensure they are centered, square to each other, level, and perfectly vertical.
5. mark the position of the legs on the floor and glue to floor with 5 minute epoxy.
Now that the frames are secure it is time to attach the various hull panels.
6. Start by laying the bottom panel across the two frames, center it and align it to the frame marks on the panel
7. attach to frame block temporarily by clamping then driving wire nails into blocks. Let some of the nail stick out.
8. Attach the transom with, structural epoxy t-88 or polyurethane glue(waterproof), clamps, and ring shank nails to the bottom panel.
9. After centering and aligning attach the stem with epoxy and marine ring shank nails.
10. With the help of another person attach the side panels to frames b, c following the same procedure for the bottom panel except don't attach to the stem or transom yet.
11. To avoid building a twist into the boat we have to be careful to bring the side panels into contact with the transom at the same time then glue, clamp, and nail. The same procedure is necessary when attaching the side panels to the stem.
12. The next step is the bilge panel, but to attach it we first have to start at the transom and work forward. First align the bilge panel so the gap between it and the bottom and side panels are minimized then nail to the transom and clamp to the stem.
13. At this point it is time to start stitching. drill holes about 1/2" from the edge of each panel every 4"-6". The hole should be the same thickness as the wire you are using to stitch the boat together with.
14. start cutting 6-8 inch lengths of wire to stitch the boat together with.
15. stitch it together working from the back to front. (It would have been nice to have a little kid for this step)
16. feed the wire through the holes from back to front, you have to do this from under the boat. After you are finished twist each wire together. Making sure the panels don't overlap one another, adjust the tension of each "stitch" as needed. As you near the stem glue and nail the the bilge panes to it. Follow this procedure for each bilge panel. Also, when approaching the frames go ahead and nail them to the frame blocks.
17. attach frame A using frame blocks, nails, and clamps.
Step 8: Putty Time!
Now that everything is stitched it's time crawl under the boat again. This time to put masking tape across the seams between each panel. Tape from one stitch to the next. It is only to keep the putty from falling through.
To mix the putty:
mix up resin as usual then add microballoons or wood flour until it is the consistency of peanut butter, then working quickly and cleanly use it to fill the small gaps between the panels, don't go over the stitches. After everything is dry remove the stitches and fill the areas we skipped earlier with more of the putty mixture.
Note: When doing the stem it will be ugly and probably take a few coats putty to build up a profile that can be rounded with a file later.
Now, get out a power sander to smooth and round everything over, but be careful not to bump the boat. It won't have enough strength until the joints have been fiberglassed.
Note: wear a respirator
Step 9: Taping Seams
Fiberglassing the boat starts with taping the seams(4" wide, 6 oz fiberglass tape), and it must be done before flipping the boat to work on the interior.
Start with the transom
1. cut enough cloth to cover the entire transom and leave about an inch of overlap around the edges.
2. Mix resin
3. Coat the transom with a small roller saturated in resin
4. Lay the pre-cut cloth into the resin
5. Carefully pull out wrinkles
6. Set the cloth into the resin with the roller starting from the center and working towards and over the edges to ensure there are no wrinkles or bubbles.
Panel Seams. Bottom to bilge panel seam first. Bilge to side panels second. Stem third(two layers).
1. Roll out enough fiberglass tape to cover the entire seam back to front.
2. Coat the area with resin.
3. Lay tape into resin
4. Use roller to lay flat and distribute resin.(don't use too much)
5. again be sure to get out any air bubbles
Use any excess resin to coat the boat if it is within a few minutes of gelling. Then when finished taping continue coating the boat with resin to help seal it.
Now Take a week off and let everything dry before sanding.
Note: long sleeves, gloves, and a respirator are absolutely needed for any step requiring sanding or fiberglassing
Step 10: Flip It Over, and More Fiberglass!
If you look closely you can see where the putty oozed through. At this point it is time to glass the frames in place. Which means removing the frame blocks from the frames one side at a time, applying a putty fillet, then resin, and fiberglass tape. Once dry remove the blocks from the other side of each frame to repeat the process.
You will also need to putty and fiberglass the interior of the hull panel seams at this point.
After you are finished with all of that the center pieces of each frame can be cut out with a jigsaw and the top edges sanded over.
Step 11: It Could Float. Lets Add Fiberglass
The entire boat has been sealed inside and out with resin, and it is structurally complete. Technically you could add paint and put it in the water now, but I think we should go a little farther and completely fiber glass the exterior of the hull. We don't need the fiberglass for strength. It is strong enough. We want it for abrasion resistance.
The process is much easier than most people think and this boat can be completely fiberglassed in a few hours.
Before starting carfully remove all dust from the hull.
1. Measure the length of the boat and cut two lengths of cloth at least six inches longer.
2. use masking tape to attach the edge two inches past the centerline of the boat.
3. Trim the cloth to the shape of the boat.
4. starting at the bilge panels(center out) mix up some resin and roll it into the fiberglass cloth
5. Apply resin to bottom panel, again smoothing it out.
6. Apply to side panel
7. sand the edge of the fiberglass to a feather edge and repeat steps for other side of boat.
note: long shirt, long pants, gloves, and respirator.
Note: Don't be afraid to pull on the fiber glass to get out wrinkles, and be sure it is fully saturated and stuck to the plywood. You must work quickly, but don't panic. This was the first thing I ever attempted fiberglassing and it turned out great. If I can do it anyone can.
Step 12: Attaching the Skeg
The first step to attaching the skeg is building one. I just used 3/4" douglass fir and cut it to a shape that fit the boats profile and was pleasing to my eye. the next step was too drill a few holes in the hull the length of the skeg. Then have someone hold the skeg against a straight edge while screwing and gluing it in from underneath. This is much easier than it sounds.
Then, just like in previous steps putty and fiberglass it in with the fiberglass tape.
Now, If I were to do it again I would have made the Skeg 3-4" deep. That is my only regret in building the boat.
Step 13: Start Sanding
since it is almost time to paint it is definitely time to sand. I started carefully with 60 grit on a few spots then stepped up to 100, 150, then 220 grit. It's just one of those thing you have to do. This is time consuming, and boring.
Step 14: Prime and Paint the Exterior.
There are all kinds of paints you can use, I decided to use exterior house paint and it is holding up pretty well so far. There are a ton of ways to paint it, but since my boat is being stored inside I'm okay with my choice. I simply rolled on primer, then rolled on paint with the shortest nap roller I could find.
Step 15: Rubrails
This is the easiest part of the project. I found some douglass fir lumber that was 14ft long and cut it into strips that were 5/4" x 3/4". Then starting from the back and working forward nailed it to the hull from the inside with ring shank nails. I then rounded the edges and polyurethaned them. Nail spacing was 6 inches.
Originally, I found shorter lengths 8ft long and scarfed them together just to try. It worked, but for something that would be bumping into things I just didn't trust it enough with such a sharp curve to the boat.
Step 16: Final Step
The final step to building this boat is the interior, rather than go into great detail I will just show pictures of what I did. There are so many ways to customize it, and since my interior is so simple I think it is best to let your imagination run wild. Remember that you can do anything you want with it like I did or stick to the plans exactly. Once finished be sure to paint the interior of the hull, and varnish or polyurethane all the wood(brightwork).
If you look at all the pictures you can see how my interior evolved. By the time you get to this point in building the boat you should be getting some decent woodworking experience. So something basic like this will be a piece of cake.
Step 17: Registration
To register the boat in florida you have to save all your receipts and file for a homebuilt title if it is going to be powered.
Remember save all your receipts because you have to prove you payed sales tax, or pay the tax on anything you brought in from elsewhere(ie online purchase).
Other than that it is a piece of cake.
Step 18: Maiden Voyage.
check out my blog for pics of the maiden voyage.