Build a Skin on Frame Melonseed (or Similar Boat)

Skin on frame boats have been used for thousands of years. They can be incredibly durable, while still being lightweight. They can also be built much quicker than any other traditional style boat. Some traditional Umiaks have been built over 30 feet long!

Why I did this:

I have wanted to build a boat that is inexpensive, yet with a traditional shape. Something light enough to be car-toppable, yet able to comfortably fit two, and sail in rough waters. I chose the Melonseed design. This was a 1900's sailboat used for duck hunting in the northeast US. It has a beautiful hull shape, covered deck so it can handle waves, and has enough space inside I could actually sleep in the boat. I looked at the designs available, and just wasn't happy with any of the plans, so I decided to design this boat from scratch.

The end result is an 85 lb boat that sails quickly, is incredibly difficult to flip, handles waves well, and can be comfortably sailed by one or two adults.

Building a boat is by no means a hard task. If you've built a workbench out of 2x4's this is just a step above that. You'll certainly have to learn some new skills, whether its shaping wood, sewing, or tieing knots. And the process is 100% worth it.

It is certainly a time-consuming project though. It took about a year and a half of working on and off, and I've got no clue how many hours I've put into this. After having this boat for a year, and making numerous improvements, I decided to make this to share my design, as well as my process. Hopefully, you will be able to take this and apply it to any boat you want to make skin on frame. I am by no means an expert in boatbuilding. You can build a Melonseed, or us this as guidelines for your own design. Take things in the direction you want.

Note: If you want to get a better view of my pictures, check out my album on flickr: Link

Edit: whew, this ended up being a lot of writing. I tried to get in every important detail. The majority of it is really in the pictures though.

Supplies

A basic overview of what is required to make a skin on frame sailboat: (I'll go into more details in each section). The materials can be extremely affordable and easy to obtain, If you choose to go with basic hardware store lumber and fittings like I did. Total cost for me was just under $400

• Long strips of wood (at least 10% longer than your boat)
• 3/4" Exterior grade or marine plywood (1 4x4 sheet) (for Daggerboard, rudder, mast step)
• 1/2" exterior or marine plywood (2 4x8 sheets)
• Several wood planks
• polyester skin
• spar urethane
• Oil-based exterior paint
• Sail material (I used a large tarp)
• Rope (for this boat 200ft should be enough for rigging, with leftovers for tieing up at dock)
• A basic sewing machine (or a needle + a whole lot of patience)
• screws + nails (preferably stainless steel)
• Hardware (pulleys, cleats, handles, etc)
• PL Premium Construction adhesive (3-4 tubes) This
• Marine sealant Like This
• + lots of small bits of wood
• SPACE: enough to fit your boat, and be able to walk around it.

Step 1: Lofting Your Design

The first step is to pick a design. I recommend looking on forums for recommendations or just browsing google. There are lots of traditional wooden boats that convert to skin on frame very well. The only boats that really cannot be converted to skin on frame are those with a large flat bottom, or parts of the hull that are concave.

Once you have a design, you will need to model the hull shape. Old boat plans came with something called a Table of Offsets, which is essentially just xyz coordinate points to map the outside of the hull. Shipbuilders would draw these out full scale and use thin strips of wood to create curves from the dots, thus making the full-size plans.

Using Delftship: I used Delftship Free, and there is This Tutorial that does a good job of explaining the process. In fact, you can just take the front, side, and top views from the plans, and eyeball the xyz points. This is a repetitive, but easy process.

Once the hull is modelled, look over it and make sure it has a relatively smooth, rounded shape. Next, Click Tools-> Intersections. click delete all, then add the values where you want to have frames. Finally, what I did was go to Tools -> Lines plan -> plot. I saved as and A3 sized pdf. It then lets you select a scale. I chose 12:1, whatever you put, just remember it. Then, use a pdf editor to create a tiled set of plans to print, scale it up by the same number you used before, and your good to print your plans.

I have attached my delftship file, and the PDF of the frames, daggerboard, and transom. I can't get it to upload here, so here's a Link: Google Drive

Step 2: Understanding the Forces on a Sailboat

Since we'll be practically designing the entire structure of the boat, its important to understand how strong these need to be. This may seem difficult, but it's actually really simple. there are four main points on the boat force on them. This is ignoring the weight of the boat, but that is evenly spread out, and not an issue for our structure.

It's very easy to build a, glue everything together, then try to twist it and move it. If it flexes too much or doesn't seem strong enough, simply add some wood beams to reinforce it.

Point 1: The Mast: When your sailing, the force of the sail is evenly split, with about half on the mast, and half on the transom. See the pictures above. With someone sitting on the boat, you should be able to push on the mast and lift them up without flexing the frame too much.

Point 2: the seats: This is where you sit, so obviously its got to support you. Sitting in the seat shouldn't flex the structure, and it should evenly spread your weight onto multiple frames.

Point 3: The transom Ther are two points of force on the transom: the rudder, and the main sheet. Assuming your main sheet is attached at the transom, it is pulling up and forward on the two upper corners. This force should be handled by the outer frame easily. The rudder is putting a sideways force on the transom, which can be a bigger concern.

Point 4: the daggerboard. Now, this one isn't actually what you'd expect. when sailing, the daggerboard acts just like a rudder, with its only goal to keep the boat sailing straight. This usually doesn't produce that much force. However, when you flip the boat, the daggerboard is what you must put your entire weight on to right the boat. This is an even bigger deal if the boat is swamped, and you've got 1000 lbs of water inside. The daggerboard case has to be strong enough to take several hundred pounds pushing on the daggerboard.

Step 3: Flushing Out the Design

Let's clarify some terms first:

• Stringers: long strips of wood that follow the shape of the boat, and support the skin
• Gunwales: The
• Hull: the bottom surface that is in contact with the water. Also the 'body' of the boat
• Bow: front of boat
• Stern: back of boat
• Coaming: A lip that goes around a hatch or opening in the deck, keeping water out.

Now we have a shape for the bottom of the hull, we need to figure out where to put the top deck, and some major support structures. So we will draw in all these elements on our plans. I chose to transfer my plans to tracing paper since the original lines printed too thick. This is the most complex step, as there is a lot involved in the design, but you can try something, make a model, and if it doesn't work, redo it.

Gunwales: For the melonseed, I used 3/4" x 2" strips for this. These need to protrude at least a bit above the edge of the plywood. I ended up recessing them 3/8" (halfway) into the frames. Draw the cross-section of your gunwales on each frame, started in the top corner, and go down.

For a boat with no top deck, you will want to make your gunwales wider than 2", and make ladder gunwales, like in the picture. This will add much-needed rigidity.

Cockpit: Next, I add the coaming around the cockpit and the seats. Since both of these are level front-back, I drew a single cross-section for all frames. The coaming serves two purposes: keeping water out and forming a rigid box structure. I only made cuts for the coaming in one frame: the one in the middle of the cockpit. I used: 3/4" x 4.5" tall planks for the coaming.

Seats: Next the seats. I made the seats and floorboards out of 3/4" thick pine. I made my seats 10" at their widest, going right up to the gunwale in most places. I made cutouts for the seats in the Three frames that form the cockpit.

King Plank: Next, I will add the King plank. This connects the rigid box of the cockpit to the forward frames. Thus the daggerboard and mast are also joined to it. This also provides a place to step when accessing the mast or any lines near it. I used a 3/4" x 9" board for this. Since my king plank is sloped, it took a bit of trgonometry to figure out how high it has to be at each frame.

Top Stringers: the stringers on the sides + bottom will all be placed against the surface of the frames, but the top stringers don't need to, so I chose to recess them. I drew these in, 3/4" x 3/4" square. The top stringers don't need to be nearly as close. I added only two top stringers. Then I put a single central peice 3/4" x 1.5" down the center from the back of the cockpit to the transom.

Keel: just make sure to have a flat bottom at least 2" wide on most of your frames so you can attach the keel. The melonseed already has this.

Lighten the frames: Next, I removed much of the interior frames. To keep things clear for myself, I drew each frame a different color. I added some holes in the sides just large enough to hold a paddle or oar in place. I made the interior so that no part of the frame as less than 2.5" thick. This is a good point to be to maintain the strength of the frames.

floorboards: Finally, I added the floorboards, on top of the lowest part of the frames. Once again, just a single cross-section view.

Tip: if you are unsure of how to do the structure, build a small scale cardboard model. You can play around with different designs and see how much flex you will have.

Step 4: Laying Out the Framework

Now that the design work is out of the way, we can get to building it!

Materials:

• Strongback
• 1/2" plywood (2+ 4x8 sheets)
• drywall screws

Tip: When selecting plywood, exterior grade or better is an absolute must. You want to find plywood with few to no knots(B or A grade if possible). Additionally, more plies are better. Something around 1/2" thick with 5 plies is really good. You can use marine plywood, and it may last longer, but it will also cost a lot more. Another thing to check for is voids. If you see holes in the edge of the sheet, where one of the plies is missing, try to find a different piece.

Strongback: First, you're going to want to build a strongback. This is a straight rigid chunk of wood that you secure the frames to. It is important that it is rigid and square because any unevenness in this will be transferred to the boat.

I took some nice straight 2x4's and made a beam 2 2x4's wide, out of staggered pieces. Make sure one side is flat, as this is where we will attach frames. Secure your strongback to some sawhorses, and make sure the top of the strongback is level.

Next, start at one end, and label the strongback every foot. Then, make marks at every position you intend to put a frame. Now take some scrap 2x4s and attach them to the side at the marked frame positions. double-check that they are all vertical (obviously not for my transom).

Frames: Now, you can transfer all your frames to the wood. I used push pins to transfer the drawings to plywood, then connected the dot. I had no problem cutting mine out with a cheap jigsaw.

Next screw the frames on. Be sure to mark the height above the strongback each frame needs to be. (top of the strongback should be the lowest point on the boat). Clamp them so the top of each frame is level, then use at least two screws to secure them.

Step 5: Reinforcing the Frame

Materials

• Stringer + gunwale wood (I used southern yellow pine)
• stainless screws (1.5" and 2" long)
• PL Premium Adhesive (1 tube)
• Planks (king plank, deck, floor, coaming)

Tip: When selecting planks, try to find pieces with a close grain and small knots. The king plank is the only one that really needs to be large. I needed a king plank just over 5' long for this boat.

Tip 2: For the gunwales and stringers, choose the wood with the straightest, closest grain you can get your hands on. Avoid knots that are larger than 1/4", but if there are one or two, you can use butt blocks to reinforce those areas. Try to purchase the largest stock you can, such as 2x6 or 2x8. These will usually have much fewer knots. For this 13' 6" boat, 14' long stock worked just fine. Also, for pine, try to avoid wood that is full of sap. I've found that these pieces are much heavier and a lot weaker. (see photos for examples)

Now its time to add the things we drew in earlier.

King plank: First, add the king plank. Mark and measure each frame location on the plank to make sure they are all square. Then screw and glue the king plank in place.

Floor: Next, glue and screw in your floorboards, once again making sure every frame is square. Now a majority of the frames should be locked in place.

Coaming: I would also recommend using a router to round the top edge of the coaming before installing it. I made wooden 'knees' to brace the coaming against the frames and make the rigid box structure. You could use the seats to brace the coaming, but since I had a stringer going between the seat and coaming, I felt it wouldn't be strong enough. Also, use longer screws for this part.

Gunwales: Once again measure the distance between frames on either side of the boat, making sure they are still even.

Seats: Finally, screw+ glue them in place

Now, it officially looks like a boat! Double-check and make sure everything looks right, and that the frames are still centered and square. (you don't have to remove the boat from the strongback yet)

Step 6: More Frame Bits

Daggerboard Case: For this I used 3/8" plywood on either side, with a solid chunk on each side. I planned to use a 3/4" daggerboard, I made the slot 1 1/8" wide. 17" long. Be sure to leave plenty of space so you can add coatings etc. Before assembling the daggerboard, put several coats of spar varnish on the inside. Then glue it together.

When mounting the case in place, I glued every possible joint with PL premium, then put a layer of caulk on top of it all.

Mast step: 3 layers of 3/4" plywood on the bottom, 2 layers of 3/4" on the top, up against the king plank. Secure this with glue and some very long screws. whatever you put on the bottom, make sure there are drain holes so water doesn't pool here.

Oarlock mounts: I used a 1.5" thick piece of pine with 1/16" brass on either side. You can also use Aluminum, 1/8". This is glued below the seat. For positioning, if your boat doesn't give you a location, sit in the boat and clamp on the oars locks. Find someplace that is comfortable.

Supports for handles, cleats, etc: next you're going to want hardpoints to attach all the hardware. I added two near the transom for the handles. Under the king plank, I glued several small pieces below where I planned to attach screws for cleats. I also did the same on the transom, and even below where I planned to screw every handle.

I also added two 3" wide planks going from the back of the cockpit to the next frame. These help support the skin when somone sits in this area.

I would recommend having some sort of 'knee' at the corners where the transom meets the gunwale. This will help to absorb the force of the rudder.

Step 7: Installing the Stringers

Materials:

• Tight-Grained wood stock (at least 10% longer than your boat)
• PL premium construction adhesive (2 caulk tubes)
• Stainless 1.5" nails
• stainless 1.5" screws (#6 -#8)

Tips: When selecting stringer wood, use the same guidelines as for the gunwales. choose screws that are fairly skinny, as if you go too large, it will compromise the strength of the stringers.

Milling: I used 3/4" x 3/4" stringers. These are fairly small, but that isn't a problem if you use a lot of them. To cut the stringers, you're going to want a table saw. A handheld circular saw can work, but I'd recommend securing it upside down to a table so it can function as a table saw. Then, be sure to round all the edges of the stringers. The fastest way to do this is with a hand plane, it usually takes a single pass on each corner.

Laying it out: Now its time to lay the stringers in place. You're going to want to put them in places that look nice, and that the wood comfortably conforms to. You should be able to tie/clamp the stringer down in only 3 places and have it completely follow the shape of the frames.

For the majority of this boat, there is average gap of 3.5" between two stringers. At the widest point, this gap is 5" this is about as far as you should go with 3/4" stringers. Any more and the skin will start touching the plywood frames. With stringers this small, and fairly gentle curves, you don't need to do any steam bending.

If the stringer doesn't sit flat on frames, take a rasp or file, and file it down to the angle it needs to be. This is especially important at the frames near the bow.

Attaching: Once you're happy with the layout, mark every point you plan to put a stringer. Start at the keel and work down. Line it up so the stringer goes just past the transom by an inch or so. Pilot drill holes, and screw the stringers to the middle frame. Then, temporarily tie them down near the bow and stern. screw the bow and stern, then you can nail or screw the frame to the remaining locations. Be sure to attach it where it naturally rests, don't try to force it into a position. I screwed stringers to every other frame, and nailed the rest.

Repeat until you get close to the strongback. then simply remove the boat from the strongback, and attach the remaining stringers with the boat upside down. Then add any top stringers you drew in.

Keel: Now is a good time to install the keel. Mock everything up and be sure you have all the supports you plan to use ready. Then just glue and screw it all in place.

I used a keel that was 3/4" thick x2" wide. Don't make the mistake I did of not putting enough material around the daggerboard slot. The keel should be made wider here to better glue the skin on. I ended this keel peice right before the curve gets steep at the bow and stern. To complete the keel, I added in a curved plywood peice at the bow and a small pine piece at the stern.

Step 8: Finishing the Frame

Materials:

• Artificial Sinew
• more stainless screws
• PL premium
• Spar urethane

Tieing the stringers: Now we have to attach the stringers at the bow. This can be hard to get right, so just do it slowly with trial and error. You will have extra wood sticking forward, and will need to find the proper angle to cut each stringer.

I started near the gunwale, pulled the stringer as close as it would go to the keel, marekd and cut it at that angle, and repeated until the stringer sat flush with the bow. I then screwed and glued the stringer in place.

As I moved down, it got harder to bend the stringers in place. For some, I used the artificial sinew, warapped around the stringers on either side, then slotted a small peice of wood through the middle. Then I twisted the wood to pull the stringers into place. Finally, I screwed this peice of wood down. It doesn't look pretty, but it works well.

Once they are all attached, use a bead of PL premium to reinforce this joint and ensure the stringer doesn't come loose.

Finishing: Before you finish, go through and make sure everything feels stiff and secure. Also, check to make sure there are no sharp corners. You can test stiffness by having somone sitting on the boat while you pull on a post stuck where the mast goes.

Finally, seal the frame thoroughly with spar urethane. I used 3 fairly heavy coats.

Step 9: Skinning

materials:

• PL premium
• 8+ ounce polyester (I used 20ft, just barely enough)
• Artificial sinew Link
• Brass tacks or Stainless staples

Tip: The 'brass' tacks they have at hardware stores are actually steel pins with brass tops. I would recommend either using stainless staples or sourcing some proper brass or stainless tacks.

Fabric: For fabric, the best source I have found is emailing george dyson ([e-mail]). He runs a web-based skin boat store. I ended up using 20 feet of his 8 ounce polyester (67" wide).

Tools:

• Lighter/blowtorch
• large Curved Needles Like This
• clothes Iron

There are lots of Instructables on skin on frame kayaks, and I would recommend also looking at those to get a better understanding of the process.

Bottom: What I did was first measure and cut the fabric to fit over the bottom. Once it is cut to size, I used a lighter to carefully melt the edges where it was cut, so it doesn't fray. Start tacking down the skin from the front, and stop right before the daggerboard.

Now, put a nice thick layer of PL premium around the keel where the skin meets the daggerboard box. try to have 1" of glue around the entire slot. Put the skin over it and use some weights to push it down. Now finish tacking the center down.

Next tack on the gunwales. You want the fabric to end at the middle of the gunwales. Finally, tack the transom, and cut the remaining fabric off. I chose to sew a small triangular patch over the bow to lock the fabric in place, you could simply use the top fabric to do this.

Top: Now measure and cut the top. I had to piece together several scraps, as I had barely enough fabric for this. Tack this in place along the king plank and cockpit. I'd recommend putting some glue around the top of the daggerboard slot, and where the skin meets the coaming.

Connect: Next, Take the artificial sinew and start stitching the top and bottom together. Start at the bow, go down one side several feet, then switch to the other side. Try to get the seam close and flush, but any gaps will be sealed later. Once you reach the stern, tack the skin to the transom and cut off any excess.

Shrink: Once its all sewed on tight, wet the fabric so its damp, then run an iron over the surface to shrink it slightly. I'd recommend testing this on a sample first to figure out what heat setting is best for your iron.

This doesn't have to be perfect, as the paint will also shrink when it dries, tightening up the skin even more.

Step 10: Finish the Hull

Materials:

• Rust Oleum High-performance protective enamel Link (1 gal)
• PL Premium
• Flexible Marine Adhesive/Sealant Like This (1 tube is plenty)
• Hardware
• Stainless screws

Sealing: Next, We need to seal all the little holes. I used the marine adhesive to add some additional seal between the transom and the skin. I also spread a layer at the joint between the daggerboard casing and the skin. On the top, I put PL Premium at the joint between the coaming and the skin. Be careful not to put too much on. Then, along the gunwales where the stitching is, I Applied a healthy amount of Pl premium, from the bow to the stern. If you go back 10-15 minutes after the glue was applied and flatten it with a spatula, you can get a fairly smooth surface. Once the adhesive has dried, sand the glue with 200 grit sand paper to ensure the paint bonds well.

Painting: Now, It can finally be sealed. I used four coats of oil paint on the bottom, three coats on top. If you want a smoother surface, sand with 200grit between every coat after the second. You just have to be careful not to sand down to the bare fabric.

Fitting out: Once that's had some time to dry, all the fittings can be added. I also added a drain plug. I added the handles, cleats, and rudder mounts. Before mounting each peice of hardware, carefully put a layer of marine sealant down. This stuff is really thick and sticky, its easier if you work slowly. This will ensure no water seeps into the wood through the fasteners.

I also added a hatch. First, the fabric was cut out into a flap. Then, dual lock velcro was scerewed down to the frames on either side of the hatch. A peice of vinyl coated polyester was sewn on top of the flap, with dual lock velcro glued to its edges. This design works pretty well, and only leaks a little when the boat is flipped.

Rub Strips: I used 1/20th aluminum (1/2" wide) for strips along the bottom. I put strips on the keel and four closest stringers. First, lightly sand the area where the strip will go. Then test fit the aluminum. I had to split some into two, since the stringers near the bottom curved so much horizontally. The aluminum doesn't like bending in the plane where its 1/2" thick. Put a bead of marine sealant, and screw it down. Along the gunwales, I put strips of wood instead of aluminum, which looks really nice.

Step 11: The Sail

Just a heads up, You'll probably need more space to construct the sail then you did to build the boat.

Materials:

• Tarp larger than your sail
• #69 size UV-Resistant Polyester Thread Like This
• 3/8" Brass Grommets
• 1/2" poly webbing Like This
• Some thick polyester fabric. (alternatively, you can use 3 layers of polytarp)

So, sails are basically just wings that point upwards. To get the most out of a sail you want to add natural curvature or 'camber' to the sail. That way, when the wind blows on it, it billows out and forms an airfoil shape. This provides extra lift, and lets you sail closer into the wind. Check out the resources below for a more in-depth explanation.

Designing: For my sail, I made a 2d CAD model of the sail. I then went 1/3 of the way back along the bottom, or 'foot' of the sail. I moved up the sail about 1.5 feet, then drew a line protruding vertically from the sail. The length of this line should be 10% of the horizontal length of the sail at that point. Following Michalak's guide for lug sails, I added a second point higher up, with once again, height 10% of the length. I then connected all corners to this point and formed a triangular surface. I took the lengths of the edges of each triangle and drew it out flattened. That became my sail pattern.

Sewing: I cut drew out this shape on the tarp, but left the material between the two front gaps, so instead I could make darts in the tarp. First I sewed the darts in, adding a second seam to keep them flat against the sail. I went over every seam twice, with the widest zig-zag the machine I had could do. After this, I used a layer of some heavy polyester fabric I had lying around to reinforce the corners. Polypropylene webbing was sewn to the parameter, and finally the I added grommets every 16". See photos for details.

Resources:

• Jim Michalak's page on the balanced lug
• More info on shaping the sail

I'd highly recommend you purchase Jim Michalak's 'Boatbuilding For Beginners'. Link Even though It's focused on plywood boats, It's got a great guide on building your own sails. He also includes lots of good stuff on making oars, rudders, and basic sailing + rowing knowledge.

Step 12: Other Bits

Rudder: as you may see in the photos, I originally started with a traditional melonseed rudder, then switched to this modern kick-up rudder. This rudder is much more effective, whereas the traditional one really didn't have enough surface area for the size of the sail. See the pictures for guidance. both pivots on the rudder are 1/2" stainless bolts. Better Quality Picture

Rudder: The actual rudder board is 29" tall by 8", 3/4" thick. I used a router to round the front and back edge. See the photos for the setup I used to cut the back edge.

Tiller: it is important this is a stout piece of wood. After switching to the larger rudder, I had a tiller snap on me under a sudden gust of wind. What I have now, and works well, is a T beam formed out of two separate pieces of wood. This reinforces the tiller the most near the rudder pivot, where it needs to be strongest. I also have an extendable tiller handle, so I can switch the tiller length, based on if there are one or two people aboard.

Hardware: I used an aluminum 1x1 tube, 1/16" thick, to attach the hinge ato the rudder (called the pintle). I used a 1/4" aluminum angle to attach the hinge to the transom (called the gudgeon). The hinge is a 3/8" stainless threaded rod. A cotter pin large enough to fit over the rod is used to lock it in place once its mounted.

I really like this hardware because it is simple, yet very strong. One change I would make if I could is to replace the threaded rod with a smooth rod, or a bolt with a very long shank.

Daggerboard: See photos if you're trying to recreate it. Although I planned to use a 3/4" thick board, I ended up using 5/8" plywood I had lying around. So far it has been strong enough, even taking the force of flipping the boat back when its full of water. Plywood, however, is very difficult to shape into a rounded edge. If you use marine plywood it will be easier. This daggerboard is more angled than the original melonseed because I used a large sail.

It may be worth experimenting with different daggerboard shapes. If I used daggerboard that was just a vertical plank, the boat would have a very strong weather helm, or tendency to turn into the wind. A small amount is good, but too much can make it impossible to sail.

Mast: I used a 2x6 to make the mast. It is 2" x 2.25" square, 13' 3" tall. I cut two pieces (side by side on the 2x4), 2"x2.25", then flipped one and glued + clamped them with PL premium. Flipping one of the pieces helps to cancel out any tendency a piece of wood might have to start to distort over time. The flipped piece will have the same tendency, in the opposite direction. If you want a really nice mast, you can spend hours with a sand belt and a drill. I instead used a router to just put a 1/2" radius curve on all the edges.

Spars: Since the sail I have is a lug rig, it has two other spars: the boom and the yard. Each are a single peice of pine 1.5" x1.5". The boom is 12' long with slightly rounded corners. The yard is 10' long, rounded so it is nearly circular. Funnily enough, I initially made the boom several feet too small. I screwed and lashed a scrap piece of wood I had lying around to make it long enough, and its stayed that way for nearly two years. Someday I'll remake it.

Oarlocks: pictured are my most successful oarlocks. The base is a 1/2" stainless threaded rod. 1/4" stainless steel rod is bent into the U shape, then looped around the 1/2" rod, then follows itself back to the start. Some clear tubing helps hold the 1/4" rod on, and also protects the oar.

I realized that it just isn' worth it for me to have this oarlock setup since I mostly sail. I sealed the holes where the oarlocks used to go, and use a kayak paddle instead.

Name: don't forget to give your boat a name!

Step 13: Testing

Now you'll want to find some body of water you can safely flip the boat in.

Test the hull first, without the sail. First, check for leaks. Then, put the daggerboard in, flip the boat, and see how hard it is to right. This is very important because you want to know how to do this BEFORE your upside down in the middle of a lake. If you'd like, try it with the sail on. You'll have to go a lot slower due to the weight of water on the sail. After testing this boat, I realized that water could still make its way into the when it's on its side. I decided to add 'knees' at the corners where the water was too close.

Now, try setting up the entire boat at home. make sure you know how to set up the sail, and practice it several times. You'll learn the order you have to set things up, and if there's anything you forgot about. After setting up the rig several times, I realized that I cannot possibly pull on the downhaul with enough force to keep the sail tight, so I added a 4:1 pulley reduction to the downhaul.

Edit: I also learned that the bottom of the transom of my boat sat about 1" below the waterline when fully loaded. When setting up the forms, I had shifted the transom down about 1" because I felt it was far too high, and the boat should be a lot lighter than the original anyway. Turns out the original plans were spot on, and that's something I probably should have stuck to.

Step 14: Sail!

Finally! Be sure to only sail in waters and conditions you feel comfortable sailing in. One of these boats won't sink when full of water, but they are an absolute pain to get OUT of the water once their swamped. Find some sheltered water, and check your local wind forecast. Try to do a first test in 6-8mph wind. This will be very light, and will ensure you can figure out any issues with your sail or boat without capsizing.

If you've never sailed before, get some experience in another small boat. There are lots of sailing clubs that would be happy to teach you. Something like a Sunfish is great to first learn on. It's much better to learn in a boat that has been proven, plus it will give you a benchmark to compare your own boat to.

I included some short videos of sailing this boat. Overall it handles very well. In the second video, you'll see the wind shifted and I accidentally Gibed. The boat was tipped a little over 45 degrees, but did not flip. I am thoroughly impressed with what this boat can handle.

If I were to build this again, on the same budget, I would try to find some lighter wood, and remove some of the redundant structures. I would probably use thin plywood for the seats instead of pine boards. I would cut larger lightening holes in the frames. The current weight of 85lbs isn't too bad, but it would be nice if it was 75lbs.