Make a Toy Catamaran




   This project is an easy to build toy boat (catamaran). Yes, there may be a lot of steps, but they are there to add detail and prevent confusion, really this project is not too difficult. This boat is designed to be built with a limited amount of tools and experience. It may not be the fastest design for a boat, but is fairly simple to build and works. It floats evenly in the water and is stable. I hope you give this a try.

Step 1: Supplies and Materials

   You will need a sheet of  1/4 inch thick wood. It can be plywood or MDF, keep in mind MDF will be heavier. You need a dowel (about 1/4" diameter) or a metal rod. You will need about 5 feet of dowel or metal rod, I used both because my dowel wasn't long enough. In addition, you will need a piece of square wood material (about 3/4" x 3/4" x 18"). I cut a 1 by 2 on my table saw to make this. For the sail you need some cloth and scissors. Solid wire and string is needed to make the rigging.
   For tools you will need a saw to make various cuts. I used a table saw and a chop saw, but a hand saw and coping saw will also be able to make all the cuts. Course grit sandpaper will be use to help shape pieces, a sander will speed up the process. For measuring you will need a ruler, square, and pencil. You also need a way to measure a 45 degree angle, I used my saw which had a laser guide to cut the 45 degree angle. If your square is adjustable, use that, otherwise you have measure out each side of a 45 degree triangle with a ruler (which isn't too hard). A hot glue gun is absolutely necessary. You need a hack saw if you need to cut the a metal rod, and drill bits (one the size of your dowels/rods and a small one about 1/16"). To waterproof the hull I used metal tape, if you don't have metal tape use duct tape or packaging tape. You need a drill driver and screws (8), they need to be about 1 inch long. It is optional but you can also use a small screwdriver and small screws in one of the steps.

Step 2: Pieces Needed for the Hull

we will need 6 different pieces to make the hull. (all dimensions are in inches)
   2- 2 x 2 1/4 x 1/4 (back pieces)
   2- 2 x 3 x 1/4(bevel cut, front pieces)
   2- 2 x 12 x 1/4 (top pieces)
   2- 2 x 10 x 1/4 (bottom pieces)
   4- Side Pieces (see picture #5)
   4- Triangles

If you already know how to cut these pieces then great, skip to step 5. If you don't know, don't worry. I will explain exactly what I did.

Step 3: Cutting the Pieces

   First, you must cut 2 inch strips of wood to make all the pieces from. Depending on the dimension of the piece of wood you are using, you may need to make multiple cuts. You need about 85 inches of the 2 inch strip (not all together though).
   I used a table saw which sped up the process immensely. Just set the fence at 2 inches away from the blade and cut away. Once you have enough 2 inch pieces, use a chop saw to cut 6 at 12 inches, 2 at 10 inches, and 2 at 2 1/4. To cut the 3 inch pieces, cut a 45 degree bevel cut on a 2 inch strip with a chop saw. Mark 3 inches in from the point of the bevel cut, and make another bevel cut like in the first picture. The piece should be 3 inches long from end to end.
   If you are using a chop saw cut a 12 inch piece. Then cut 6, 2 inch wide pieces off that. Cut that piece (or a new one if you used it up) at 10 inches. Cut 2, 2 inch wide pieces off that. And finally, cut the piece at 2 1/4 inches and cut 2 more 2 inch pieces. Alternatively you can start by cutting a bunch of 2 inch wide pieces and then cutting them to length. Cut the 3 inch piece exactly the same way as noted in the previous paragraph (in italics).
   If you are using a hand saw, I would suggest cutting the pieces to length (6 at 12 inches, 2 at 10, 2 at 3, and 2 at 2 1/4) before you cut them to the 2 inch width in order to avoid making useless cuts (and therefore waste time). Use sandpaper to sand the shape of the 3 inch pieces. Shape as seen in the picture.
   If you do not wish to make a bevel cut or do not now how to, you can always sand the corners off instead of cutting them off. Remember, it does not have to be absolutely perfect (it helps). Just get the general shape.

Step 4: Cutting the Side Pieces

   All that is left to do is cut 4 of the 6, 12 inch pieces to be side pieces. Start out by marking the corner of the piece at a 45 degree angle just so a right triangle will be cut out of the piece. (you will need the triangles later on but they don't need to be an exact size, the side piece needs to be exact however). Use whichever saw you are using to cut the piece as seen in the picture.

Step 5: Sanding the Pieces

    In order to make the pieces fit better we need to sand the points off of the edge pieces and the 3 inch pieces with the bevel cut. For the edge pieces, sand the point until it looks like the edge piece in picture #1. Sand off about 1/2 an inch. Do this for all 4 side pieces.
   For the 3 inch pieces we want the same type of effect, but instead we are sanding the whole edge instead of a point. Picture #2 illustrates what needs to happen.
   The triangles also need to be sanded. Sand them the same way you sanded the side pieces. Make sure to sand all of the corners. In the end they need to look similar to the final picture.

Step 6: Assembling the Hull

   To assemble the hull, start by gluing one of the triangles to the bottom side of a side piece. Then glue another triangle in the same fashion towards the rear of another side piece (see picture #2). Look at picture #3, you will need to apply glue to the entire bottom face of the side piece and triangle. Quickly place that piece an a bottom piece before the glue dries. At this point it should look like picture #4. Attach the other side using the same method.
   Now you need to attach the back and front pieces. I attached them using the same method, so it isn't hard. Look at picture #6, the "U" shaped face is where you need to apply glue. Stick the back piece on and let the glue dry. For the front piece there are 3 faces to apply glue to (picture #8). Once the front piece is attached, it should look like picture #9.
   Last you need to attach the top piece. Apply glue to the whole top face ALL THE WAY AROUND (picture 10). Then immediately place the top piece on top before the glue dries.
   Remember, you need to do this step twice to make two hulls which will be connected later on.

The last picture show what the final product of this step will be.

Step 7: Sealing the Hull

   You will notice a large gap on the front of the hulls, we need to seal these gaps off. get two pieces of wood similar to the ones in picture #2 (about 2" x 1/2" x 1/4"). As is , these pieces won't work very well, sand them so they look like the one in picture #4. Glue one on both the hulls so that it looks like picture #5.
   Next all you need to do to seal the hull is to fill any holes or gaps with hot glue and smooth it out. Apply an a lot of glue to the gap and then smooth it out with an eraser.
   Last you can sand the hulls so that they will look better. Look at picture #9. Sand it so that it looks like picture #10. Sand down all sharp corners.

Step 8: Completing the Hull

   Cut your rod (metal or wood) into two 10 inch pieces. Then cut your square wood material into four 2 inch pieces (I cut two extras just in case they split). Then drill a hole in the middle of each of the 2 inch pieces. The hole must be the same size in diameter as the rods you just cut. Press a piece of wood onto each end of a rod (picture #5). Place the rod/wood assembly on the left hull so that they are flush with the left edge. One rod should be near the rear and the other should be 2/3 of the way towards the front.  Drill pilot holes on both sides of the rod and attach screws. Repeat for the other rod. Make sure the wood didn't split. Then just repeat the process with the right hull. Make sure the rod/wood assembly is flush with the right side of the right hull.

When finished, it should look like the last picture.

Step 9: Add the Mast

   To add the mast, cut a 10 inch piece from the square wood material. Then place that piece on top of the two rods, make sure it is centered (picture #2). Mark the piece in two spots, both in the center of each rod. Make a line at those marks and drill two holes, both in the center of the wood. Slide one the the hulls off and insert the piece you just made. Re assemble the hull so that it looks like picture #6.
   Cut a rod at about 18 inches, this will be your mast. Drill a hole that is the same size as the mast in the piece of wood (drill it almost in the middle of the entire boat but closer to the front). Insert the mast into the hole and it should look like the last picture.

Step 10: Adding the Boom

   The boom needs to be 1/2 the length of the mast. Cut a rod at 9 inches. Cut a 1 1/2 inch piece of the square wood to attach the boom to the mast. Then drill a hole for the boom to go into (see picture #3). Drill a hole for the mast to go into perpendicular to the hole for the boom (picture #4). Enlarge the hole by wiggling the piece while the drill bit is in the hole. The mast hole must be large enough for the piece to slide easily and move freely onto the mast. Stick the boom into the proper hole and set that assembly aside for a while.
   Cut a cube out of the square wood material. Then drill a hole in the center of the cube so that it will move freely when slid onto the mast (same as the other mast hole you drilled). You can sand the cube if you want so it looks better, but it is not necessary.
   First slide the cube onto the mast and then the boom assembly. It should look like the final photo.

Step 11: Making the Sail

   Cut your cloth into an 18 x 9 rectangle. Then cut the rectangle diagonally to make two equal triangles. Cut enough 1 inch strips to go all the way around the perimeter of the sail. Glue one triangle on top of the other, apply glue all the way around the edge. On one side of the triangle, glue a strip on an edge so that the cloth does not hang over the edge but is flush with it. Do this to all 3 sides. Now curl the strip around the edge and glue it on the other side. Finish all three sides. Make sure that it created a tube, you will need it for the rigging. Trim all the corners to expose the openings of the tubes.
   The finished sail is the final picture.

Step 12: Rigging the Sail

   Straighten out two feet of wire and strip a couple inches off one end. Insert the wire into one of the tubes on the sail. push it through until it comes out the end. Hot glue the string onto the wire. pull the wire back through the tube. Leave about 1 foot extra on each end of the string and cut it. Repeat this process for all 3 sides of the sail.

Step 13: Attaching the Sail

   Drill a hole at the top of the mast, at the bottom of the mast, and at the end of the boom. The holes at the bottom of the mast and the end of the boom need to hold 2 strings. Insert the top end of the mast string into the top mast hole and, insert the bottom end of the mast string into the bottom mast hole. Tie a loop into the bottom mast string after it is through the hole. Stick the top end of the mast string into the bottom loop, pull to tighten. Tie a knot when the string is tight.
   Insert the mast end of the boom string into the bottom mast hole, tie it in place with a knot. Insert the outside end of the boom string into the hole in the boom.
   If you decided to use the out string, insert it into the hole in the boom and at the top of the mast. Tie the ends to keep it in place.

Step 14: Tension the Boom String

   Depending on the amount of wind, you will want to have the boom string at different tensions. Tighter for more wind and looser for less wind. Drill a hole in the block of wood that attaches the boom to the mast, it needs to be at a 45 degree angle so it goes in one side and comes out the other (picture #1). Insert the end of the boom string that is not tied down through the hole you just created. Tie a loop AFTER the string is through the hole. Pull the string tight and mark where a screw should be placed so that the loop can go around it. Attach a screw at that mark and at a place about 1/2 inch or so closer to the mast.
   If you don't want to adjust the tension then just tie off the boom string at the end of the boom.

Step 15: Final Rigging

   The last string to attach is to control how much the boom rotates. In the wood block that the mast is attached to, drill a hole in the same place as the hole in picture #1. Insert a string through the hole at the end of the boom and through the new hole (I drilled 2 holes because the first hole was not big enough). Tie the string onto the boom hole so it won't come out. The other string can be used to control the boom (if you want, you can attach it to a servo and create a RC boat, all you need is a rudder). That finishes up the rigging.

Step 16: Waterproofing

   To waterproof the hull apply a half strip of duct tape or metal tape to all of the joints on the hull. The tape should border all of the edges and corners on the hull. Place the hull underwater and check for bubbles, patch all holes with hot glue or tape. (make sure to empty and dry the hull before patching holes)

Step 17: Sail the Boat

   All that is left to do is sailing the boat. Fasten the boom control string so that the boom can move in the ideal position depending on the wind. Place the boat into the water and watch it float around. It is also fun to use in pools or anywhere else a toy boat would be used. I might add a rudder and hobby servo system to this boat in order to gain remote control. I hope you enjoy your boat.



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    30 Discussions


    8 years ago on Introduction

    Great 'ible! Two suggestions, one for convienence, one for safety. In step 8: Completing the Hull, when you go to drill the holes for the rods on the square wood blocks, clamp two of them together and drill through both at the same time. Make sure they are lined up straight and you are drilling straight. (use of a bench press is recommended) And don't forget to clean up the kerf.

    And #2.
    Step 10: Adding the Boom, I would suggest using a slightly larger drill bit to enlarge the hole rather than wiggling the block of wood. The wood could bind on the drill bit, spinning it around. It probably wouldn't kill anyone, but it can break a finger. Or worse, jam one.

    Everything else looks great. Looks like something my 7 year old son and I can do one Saturday.

    2 replies

    Reply 8 years ago on Introduction

    Yes wiggling the block of wood around is rather dangerous in that respect. I noticed that pine is the only type of would that I have to do that to. Also a small forstner bit can be used and doesn't have this problem. For me I always can never find the exactly right sized bit (my shop is a mess) so I resort to wiggling the wood.


    Reply 8 years ago on Introduction

    You should talk to this guy.


    8 years ago on Introduction

    I drew a google sketch up of this, its a little bit off but the scale is right. A bit of the pieces are dodgey...


    8 years ago on Introduction

    Speaking as a sailor of a full size catamaran I see 3 things which can be done to improve things. First and easiest, a jig sail (in front of the mast) will help the boat point to wind much better. Add a couple of stays on the left and right sides of the mast and one on the front of the mast. Attach the jib to the forestay (front one). You can put a line between the two hulls to attach the forestay to. It'll naturally form a "v" shape under tension, which will help the forestay stay in place. This is how most hobie cats are rigged (I had a hobie 18). Second, your hull design is flat which is going to cause the boat to slip sideways when then wind is coming from the side of the boat. Take a couple of pieces of hard thin plastic and tack them on the side as leeboards. I'm thinking that the plastic "sticks" you get with a starter vegetable plant would work well size size. Anyway, add a pair of rudders (movable or not) and you're done. You can make them of the same material. Third, for the main sail you might want to add battens to help it maintain it's shape. You can probably just add some of those plastic stir sticks you'll find a most coffee places. Add a bit compression tension so they'll want to bend slightly. You'll want to probably add one or two. If one I'd suggest putting it around 2/3rds of the way down the sail from the top tip.

    3 replies
    erehwonkid cudi

    Reply 8 years ago on Introduction

    I mis-typed a bit. It should be "jib" not "jig". I'll put together a line drawing and get it posted soon.


    Reply 8 years ago on Introduction

    You could use a fan to propel the boat like an airboat. But the fan you use must be strong enough to push the boat. I don't think a computer fan has that kind of pushing power. If you have one that does, great, use it. Otherwise you could use a dc motor attached to a propeller for a model airplane.


    Reply 8 years ago on Introduction

    Yeah that and a rudder would open up more possibilities, however the idea of this instructable was to be simple. I decided to leave some parts out seeing as it is a toy boat. If I was to make it remote control I would definitely add hydrofoils.


    8 years ago on Introduction

    Ok, this is a bit of a lame drawing, but hopefully enough to get the point across.

    First, with a typical sail boat that uses stays to hold the mast upwards you arrange them as to create a tripod of sorts. There's always one at the front, centered on the centerline of the vessel, and then two which slant backwards towards the sides and rear of the vessel. On a catamaran since you don't have a hull to attach the forestay to you'll have a line which spans the front of the boat between the two hulls. The forestay attaches to the middle of that line, and when under tension the spanning line will form a slight "v" shape (although upside down).

    Regarding the picture I've attached (it's lame I know), the "main" picture is a side view of the vessel. I've colored the stays in red, with the hulls and mast being black. The largest and centered image is the view from the side of the boat. The two rear stays attach at the same point near the top of the mast and come down at the same angle to points the same distance back on the hulls. The boats I've sailed generally have these fairly close to the outer edge of the hull. The upper left image is a image of how the spanning line (it has a name but I don't remember offhand what it's called) and the forestay are configured. The hobie 18 I had used two eye hooks near the top inner edge of the hull for attachment points, and the line was not tight, but also not really loose. With the forestay attached to it then you'd have tension, and also the "v" shape I mentioned.

    The jib sail I mentioned will be attached to the forestay. The sail on the hobie had a leading edge which would unzip so you could wrap the forestay with the sail, but you can get the same effect with loops of line, or rings. I'd suggest looking for pictures of sailboats on the web for ideas on how to attach one to this model.

    2 replies

    Reply 8 years ago on Introduction

    Yeah, you could cut out foam into the correct shape and insert it into the hulls. This would really help if there happened to be a leak.

    tommy tinker

    8 years ago on Introduction

    If you cut the sail as in the pic it will make an airfoil shape and be more efficient. Just a thought, nice 'ible'.

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