How to Construct a Simple Boat




Introduction: How to Construct a Simple Boat

Yes indeed, it is possible to build a boat without fiberglass or epoxy.
I can hear you now, those that gasp in horror at such a notion, but believe you me it works.

This instructable demonstrates the simple construction of a scow. While all construction details are drawn from others plans and instructions the overall shape is my own making.
Most scows have straight sides, resembling a box, mine however has curved sides, making the process of building only slightly more difficult.

Step 1: Materials

The instructions given may, in places, not correspond to the actual boat that I made. I took several sets of instructions and used my discretion to combine them into my project. The intent of this instructable is to pass on knowledge in order that you yourself may be able to construct something of your own. So in places I may inject or suppliment some information or process that I may have not used but that would be beneficial to those reading this instructable.

On to the stuff you'll need:
Prices change every day so I'm not going to list any.

Wood, pine or cedar may be used throught except where noted. I got my lumber from Home Depot.

- sides. 2 peices as clear of knots or defects as possible. mine were 10 feet long pine 10 inches wide.

- planking. (goes on the bottom) do the math, at 10 feet long you'll have to cover a little over 120 inches for this project and it's a good idea to buy a little extra. take a calculator when you buy your lumber. 6 inches seems to be the preferred width for bottom planking but 5 or 8 inches will do just as well. They should be about 3/4 of an inch thick and at least 4 inches longer than your boat will be wide. Also with these you want them to be as free of knots as possible.
I bought some cedar fencing boards that were on sale, they were 5/8 of an inch thick and 8 inches wide and 6 feet long. so needing to cover 120 inches with 8 inch wide boards means I needed 15 boards. Because my boat is only 3 feet wide and tapers to 2 feet at the ends I had a few leftover boards.

- keelson. (this will go inside on the bottom) it needs to be longer than the sides because it will be curved. the one I bought was a pine 1x5 12 feet long

- middle seat. a pine board supported by cleats. you'll need a board 3/4 to an inch thick and around 6 inches wide or wider. Also two peices 12 to 18 inches long and about 2 inches wide for the seat to rest on.

- end seats or decks. just use leftover planking, or buy extra, to cover the topside of the ends with 2 boards each.

- ends. 2 peices of oak an inch thick and 6 inches wide will be needed. They should be as long as you want your boat to be wide, minus the thickness of both sides. You may also choose to cover these with another peice of cedar or pine.

- forming brace. (This is needed if you intend to curve the sides as I did. If you're just going to leave the sides straight you don't need this) Ideally use a peice of hardwood as wide as the sides and as long as the boat will be wide. I, however, just used some pine scraps that were long enough.

- knees. (if your boat has straight sides skip this) these are peices that will go into the corners to add strength. you'll need 4 peices of 3"x3" oak about an inch thick.

- Oars. (assuming you make your own) there are plenty of instructions on these so I won't provide one.

Tools, others help immensely but these will get the job done.

- tape measure.

- saw. a simple hand saw will work

- plane. you can usually find a little one at hardware stores fairly cheap

- hammer.

- 2 peices of rope. at least 6 feet long

- paint brush.

- metal putty knife or flathead screwdriver

Other Supplies

- paint. You could go the expensive route and use marine grade and anti-fouling bottom paint. But face it, this is a cheap boat. Exterior latex house paint will do just as well. Two coats of white exteroir latex primer followed by at least one coat of your preferred color is enough. A dull grey, lead color, is suggested for the inside and a darker color of your choice for the outside.
You'll also need a small can of white oil-based paint for caulking.

- paint thinner.

- caulking. for those of us that don't live in a boatyard this is actually just cotton that will be wedged in the seams of the boat. This can be procured from marine supply stores or you could just go down to Walmart and get Peaches and Creme brand worsted weight cotton yarn in whatever color you choose (it won't matter you can't see it).

- putty. The instructions I looked at said to putty over the seams but were otherwise inspecific about what that was. I just used some wood filer from the hardware store because I didn't know better at the time. On further research I would suggest roof calking, the black tar-like stuff. you can find it in a tube or sometimes in a big gooey bucket.

- saw horses. three words people; convient working height. you can do all this on the ground but it's much easier on your back if you lift the boat up about 3 feet.

- 5d (pronounced five penny) galvanized nails. about a pound and a half should be enough. I just bought a box.

I think I covered all the basics but if I missed something it'll show up in one of the steps.

Step 2: Forming the Sides

Start by shaping the sides.

To taper the ends measure 2 to 2 and a half feet from each end and mark it. Then measure how wide you want your ends to be and connect your marks.
Usually the ends are the same width, about 4 inches.
Clamping the peices together helps to ensure both will be identical, which is important.
Once the ends are tapered take the plane and round off the edges to a smooth, gradual curve. If you don't it will make the keelson much harder to put in.

I made my ends kinda different. The bow is only 3 inches wide and the taper starts 2 feet from the end. The stern is 6 inches wide and the taper also starts 2 feet from the end of the board.

Step 3: Placing the Ends

If the sides of your boat are straight just nail them on and square up the boat before planking.

If the sides will be curved first mark the center of each side, then nail the brace in place. remember to leave the nail heads sticking up so you can take them out easily.

make two loops out of the rope and fit them about a foot over each end.
Starting with the stern first put something, a pipe or scrap peice of wood, into the loop and twist until the distance between the two peices is just enough for the end to fit in. nail it.
Leave the rope on the stern and then tighten down the one on the bow, nail that one in place too.

Once the ends are nailed in place mark the inside of a corner on a peice of paper (or use a bevel gauge). Check all corners to make sure they're the same. If they're different you're ends aren't square and you need to adjust it. Make sure one side is stationary and move the other forward or back until the angle at the ends are the same. There are more complex and better ways to square a box, but this will work. Once every corner has the same angle cut out the knees from oak or a similar hardwood and nail them in place, flush with the top of the boat.

Once the knees are on you can probablly take the ropes off, but I waited until after the first peice of planking went on.

Step 4: Planking and Keelson

First place the keelson.
If you haven't done so already make a notch in the brace just wide and deep enough for the keelson.
Mark the center of each end to ensure the keelson gets centered. Then nail through the stern into the keelson to secure it in place. Bend the other end down to the bow and mark where it needs to be cut and the angle the cut needs to be. After cutting nail it in place.

If it's too rigid to bend where you need it, try soaking a towel in boiling water and placing that on the board for a few munites and trying to bend again. This may have to be repeated several time before it works.
If that doesn't work or you're afraid of burning yourself you could just cut a kerf, or several, in the board. A kerf is a shallow, less than half the thickness of the board, cut on the same side you want the bend: if you want to bend it up cut on the top of the board right where the bend will be, if you're bending it down cut on the bottom of the board. (I hope that made sense)

Once the keelson is in place start planking.

Start at one end and work over to the other. Cut the board about 4 inches longer than it needs to be and nail it onto the edges of the sides, and the bow and stern for those peices that go over them. Also nail into the keelson, staggering the pattern as you go. Three or four nails at each joint is plenty.
Once the bottom is on the nails in the keelson will need to be clinched. If you don't have the proper tools and someone to help you can just hammer the nails down, or to get rid of the points you can take a pair of pliers and bend the tip about 70 degrees and then hammer the nail down back into the board.

Step 5: Seats

First make the bow and stern seats, or decks if you'd prefer to call them. This is done with the same boards you used for planking the bottom and in the same manner. Put two boards on each end.

For the middle seat, the one to row from, first put in cleats for it to rest on. These should be about 2 inches wide and about a foot long. Place them approximately where you want the seat to go and then nail them in the same manner the keelson was (or just use screws).
If you're not sure where you'll need the seat you can make your cleats about 2 feet long and place them a little forward of the center of the boat. Cut the seat to fit in the center as you can always cut it further to fit closer to the end of the boat.

Step 6: Caulking

Once your boat actually looks like a boat, it needs to be made watertight. If you made all your joints nice and tight you may not even need to caulk the boat as the wood will swell and seal everything up once it gets wet. But if you're like most people you'll need some extra help.
Now some people may be shaking their heads saying "you'll never be able to stop water from getting in without epoxy, fiberglass and lots of resin."

Actually all it takes is some cotton and putty. The putty will keep the water out until the cotton swells, the cotton will keep the water out until the wood swells

The simplest and surest way to do this is to just put flanel strips soaked in paint between every edge when putting the planking on.

But then you'd miss out on actually caulking a boat.
To do this you need some caulking cotton.
The easiest stuff for me to get is some 4-ply worsted weight 100% cotton yarn from walmart (peaches and creme brand), I've read about professional boatbuilders that use it, so if it's good enough for them...
Once you've got that some people will try to tell you you need a couple different size caulking irons and a special mallet and try to sell you some other specialized nautical boat building tools. For one small boat, especially a scow, you simply don't need any of that. You can caulk the whole thing with a thin flathead screwdriver, but since you need it for the putty anyway a metal putty knife will work better.
Take a peice of yarn a bit longer than the seam and start forcing it into the gap at one end. Push it about halfway through and then move across the seam trying to get the same depth all the way. If the gap is wider than the yarn simply fold the yarn onto itself and twist it a bit, then force that down the same as you did before.

After caulking the seams will need to be payed (or saturated with thinned, oil-based, paint). To do this get a small can of oil-based paint and thin it 10 to 20% with some mineral spirts or turpentine. Just brush this into the seams with a thin, short-bristled brush.
Another way of doing this would be to take a plastic "Dawn" dish soap bottle, a cork to fit it, and some 1/4 inch copper tubing and make a paint applicator. Just drill a hole in the cork for the tube, the tubing should be long enough to go almost all the way to the bottom of the bottle, put the tube in the cork and bend it about 90 degrees, then hammer the end down so there's just a slit for the paint to escape out of and file the edges down to about 1/16 of an inch thick. Then just fill the bottle with thinned paint and you've got a great applicator for future boats.

Then all the seams need to be puttied. Traditionally this is a mixture of whiting (calcium carbonate) and linseed oil or just boiled pitch. I'd try roofing caulk, the black tar-like stuff. I, completely ignorant of all this at the time of building, simply used wood putty. I may yet have to rip out all my caulking and start over, we'll see with time.

If you know you'll want to caulk the boat you can leave a 1/16 inch gap between each board when planking.

Due to some rough handling of the boat, I sprung a leak. To fix it I tried using putty made with whiting and linseed oil. The encyclopedia britanica describes whiting putty like so:
Whiting putty of a high grade consists of 85 to 90 percent whiting blended with 10 to 15 percent boiled linseed oil. Prepared putty should roll freely in the hands without exuding oil.
My first mix was probablly a little too gooey, but having fixed that I decided to recaulk all the other joints just in case. I found that it's a bit easier to mix in a shallow bowl or paper plate. you'll know it's the right consistancy when you can roll it in a ball freely but if you let it sit in your hand it sticks.

Step 7: Painting

Using a primer give the boat two thick coats inside and out. Then paint the inside a light color that won't reflect too much light, a dull grey works well but doesn't always look great. A slightly off-white color will work as well. Then paint the outside a darker color. To give it more appeal change colors or paint a stripe at the waterline, or where you think the waterline will be.

Instead of painting the rowing seat I finished it with linseed oil.

Step 8: Check Your Seams

Next you need to make sure you don't have any serious leaks.
If you live near a river or lake or other calm body of water that you can put your boat in without anyone bothering it just launch it and leave it for a couple days. It may sink but after a couple days in the water the seams should have swelled up making it water tight. If it did sink pull it out of the water, empty it and launch it again checking for leaks.

If you don't have easy access to water you can just take it outside and set it up on sawhorses or cinderblocks, make sure it's well supported so the planking doesn't pull away from the sides under the weight of the water. Then fill it half full of water (or enough to cover all your seams). It will probablly leak a bit the first few days but after the third if water is still leaking out mark where it's comming from, dry out the boat and seal those spots by recaulking them. then repeat the process until you've got a sound boat.

Step 9: Launch It

Once everything's ship shape as far as the hull goes, launch your boat. If you haven't made your oars yet, just borrow a paddle. Take it out to see if your seat is where you want it. Take on a passenger, if any are willing, and see how it handles with weight in differing positions. Stay out for longer than just a float check, make sure to pay attention for any leaks.

Step 10: Oars

make some oars and attach them to your boat. Direction and tips for this can be found in step 1. If you live near any sort of marine or boat supply store just go pick up some oarlocks.

Attach them to your boat and row it.

Some sites to check out for making your own oarlocks:

The oars I made are pretty ugly but they work great. I just carved them out of two 2x4's. If you make oars out of lumber like this it's best to use one long peice to cut them out of rather than two. The blades on the oars are narrow and long, while it may be rather slow to start a heavy boat they're not much different than conventional oars once you get going. Also they don't cause as much overall strain, letting you cover long distances with less effort.

The overall design of the oarlocks, as far as I can tell, is attributed to Phil Bolger, though I have read vague referances to "fishermen" having more or less pioneered them. who knows. Anyway, they're pretty much just a block of wood attached to the sides with a bolt in it and a peice of rope to attach the oars. The rope should have a loop in both ends and to keep it from comming off I used a fender washer near the head of the bolt. The oars should fit tightly in the rope loops, with just enough slack to allow you to rotate them, or feather, as you row. It doesn't really matter if the oars are in front of or behind the bolt while rowing, however, it's best to have them behind, where as you row they strain against the rope, because if you should need to let them go they'll just rotate and trail alongside the boat.

Step 11: Sailing

I finally finished a sail for this boat. It's a small spritsail around 40sq feet.

I put in a mast step and partner about 25 inches from the bow. The mast and sprit are both about 1 and 3/4 inches in diameter. I cut them out of a pine 2x4, they're both just under 9 feet in length. I made two small cleats for the main outhaul and the sheet, and one really small one that goes on the sprit to control the snotter. I don't have anything specifically for the brail line, for now I just run it back to the cleat for the sheet. I'll probablly make a side-mounted daggerboard just to keep things simple, but for now I made a curde daggerboard/leeboard out of waferboard. It'll help decide where the daggerboard will eventually go. For now I'm just using a paddle to steer with but I'm considering a rudder, we'll see.

Step 12: Evolve

Eventually I did make a barndoor-type rudder with a steering yoke rather than a fixed tiller, it turned out to be too small. I also added a shallow  keel, a 2x4 bolted through the keelson. My original 2x4 mast had a knot in it and snapped in half one day, luckily I hadn't put the boat in the water yet. So I made another one, this type called a cooper's mast, it's mostly hollow, made from clear pine with oak caps. A new sprit was made from laminating two peices of pine together and rounding it, a groove secures the peak instead of a point and an extra 12 or so inches extends beyond the peak so a flag may be flown. Lastly I rigged a type of traveler to control the foot of the sail using eye-bolts in the rear deck.

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    3 years ago

    LOVE IT! How does she sail and how much does the hull weigh?


    6 years ago

    you havent read boat-building and boating by any chance have you?


    Reply 6 years ago


    12 years ago on Step 6

    When you assemble the Pieces, put "Liquid Nails" construction adhesive on all joining surfaces before fastening them. There won't be any leaks at all.


    Reply 12 years ago on Introduction

    DONT, i heard it sucks. use expoxy.


    Reply 12 years ago on Introduction

    You HEARD, I built 17 boats with it.


    Reply 6 years ago

    I have used liquid nails as well. Don't use the "project" liquid nails. The original construction adhesive works great. I've used it to glue plywood to douglas fir chines. I used nails and/or screws to make the initial hold while the liquid nails sets. Then I just leave them in. It is pliable, and have never had a leak. rbodell, building is better than hearing.


    Reply 12 years ago on Introduction

    Yes epoxy is better, but the idea here is to build a boat WITHOUT resine.


    7 years ago on Step 7

    Oh, and Linseed Oil is pretty useless for anything nowadays. Smells good, sounds good, but is pretty obsolete.


    9 years ago on Introduction

    does it leak how much wait will it hold and would this maby make a ok survival raft


    Reply 9 years ago on Introduction

    Your sentence structure is almost as poor as your spelling, bordering on incomprehensible. However, to answer your questions; I don't know exactly how much weight it will hold, no it will not be suitable as a survival raft or stored tender or lifeboat, and yes it will leak unless kept in the water. This type of boat is best suited for calm, protected waters and requires constant maintenance.


    10 years ago on Step 6

    I was involved in Irish currachs tar covered lightweight boats. I was also the researcher and as such I covered (literally) ALL sorts of boats from light skiffs to a 45T Donegal double-ender. I was also a painter by profession for 20yrs.
    This is a project I would consider within the scope of any DIY enthusiast. Well done. Very clear concise instructions. The jaunty sail sets it off wonderfully - though I'd suggest you use a lee-board to stop yaw/drift.
    One tip I'd give - and it will settle ALL discussion on caulking. As soon as the boat is ready sink it for a few days. This will cause the wood to swell (helped if you use undercoat only on the interior as that allows the wood to breath) the swelling will seal all 'gaps' and it can be done more than once as the sides dry out and take in water.
    A fair wind to yo lad.


    Reply 9 years ago on Introduction

    One of my least favorite things in this world is hot roofing tar. It is dangerous in many ways and one drop of sweat and flying tar will hit you every time. Surely there must be some modern tar that does not require radical heat to melt and use. I have felt the bite of tar as it penetrated my flesh.


    Reply 9 years ago on Introduction

    Ya, just but roofing caulk. It's pretty much the same thing but does not need to be heated and comes in convenient tubes.


    9 years ago on Step 12

    Nice job on a traditional craft. Speaking of which, whilst Beard is excellent, Gardner's Classic Small Craft is superb. Anyone interested in traditional boats should read it. His dory book is pretty good too.
    Dig around through here for all sorts of projects, boats included.
    For a skiff look around for, How to build a Brockway skiff by Timothy Visel(lost the website sorry)

    For those wishing to build in plywood, yes you can. Use exterior grade for cheapness, marine grade if you can afford it. Use Payson's simplified chine log method to avoid end grain problems, nails and screws don't hold so well in end grain. Frame around transoms with 1by 2 or 1 by 3 leave enough proud so you can bevel it.


    13 years ago on Step 4

    Could you use a large sheet of plywood in place of the planks? Seems like this would reduce the amount of caulking required. Very nice project. I'll have to try making a boat one of these days. I like your simple plan. Thanks!


    Reply 12 years ago on Introduction

    Plywood doesn't swell like planks do so the sealing would not be as good between the bottom and sides..


    Reply 10 years ago on Introduction

    Sika Flex adhesive caulking may be sent directly from heaven. Not only will it hold a craft together it is also paint friendly and its easy to work with as well.
    My current thought is to build a cross between a John boat and a canoe. In other words it would in essence look like a long narrow box with the bow sloped and the stern at 90 degrees from the flat hull. Following waves can be a real problem here and a sloped stern is an invitation to get dunked. I have even seen boats here used for rescue in heavy surf that have flotation built into the floor and large holes cut in the sides so that water always sloshes around on the floor. It is tropical here and wet feet aren't an issue and these rescue row boats would launch from the beach against 10 foot waves and self bail while the life guards rowed to the vessel in distress. They were about 12 feet in length and built wide with fairly high sides so heavy pulling on long oars was the norm.