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DIY stitch and glue Drift Boat Building -- Drift Boat Blueprints -- Online Plans

Roll over the boat

At this point it is almost time to roll over the hull and begin work on the inside of the boat. But before you roll the boat over, make a boat cradle out of 2"x4"'s to hold the boat up off the shop floor. Lay down two parallel eight foot 2"x4"'s on the floor of the shop, about four feet apart. Then place two six foot 2"x4"'s across the ends of the first two boards and screw the corners together with drywall screws. These four boards will hold up the boat and protect it from any wayward drywall screws, nails or other shop-floor boat gougers. You really should have a helper at this point. Grab the boat by the nwale, and lift it up onto its side. Lift up on the boat as you turn it over to minimize the weight on the sides of the boat as you make the flip.


Once you have the boat turned over, it is time to make and install the gunwales. To make the gunwales, you'll need four lengths of gunwale stock. Good vertical grain Douglas fir can be used, or oak, or ash. Mahogany does not make good gunwales. Try to find boards that are long enough to make the gunwales in one piece. Sixteen feet-one inch is the minimum length for one-piece "outwale" stock. Fifteen feet-eleven inches is the minimum length for one- piece "inwale stock."

Material list: gunwales

  2) 5/8" x 1-1/2" x 12" Inwale stock   2) 3/4" x 1-1/2" x 193" Outwale stock   2) 1-1/8" x 2-1/2" x 4" Oak or ash oarlock blocks 12) 1-1/8" x 1-1/2" x 2" redwood or cedar spacer blocks   4) redwood or cedar tapered spacers. These spacers are 1.5" high, 24" long, and they taper from 1-1/8" at one end to 0" at the other end.

Gunwale installation--general summary of events

Now you are ready for the gunwale assembly. One way to make gunwales to install them so they are bolted into place, but not glued. The first step in this gunwale assembly is to remove all of the strongback stations. In order to do this, you will need to cut the fiberglass that is covering the six screw heads (these screws are located just below the gunwale edge of the hull) that are still holding the stations in place. You should have pressed some candle wax into the phillips head slots of these screws in an earlier step. Cut away a small circle of fiberglass and back out the screws. When you take the stations out the boat will collapse inward a little, losing some of the beam it had before you removed the stations. But don't worry about it. You will regain the shape of the boat in a future step. Before you can mount the gunwales, you will have to put the stations (loosely) back into the boat. These stations must go back in order to regain the shape of the boat before you install the gunwales. But before you put these stations back, you have to cut a notch out of the top corner of each station in order to make room for the inwale. You can't reuse the screw holes at the top edge of the boat (the wax filled screws that you just removed) because these holes are about to be covered with the gunwale. But you don't have to fasten the rib stations at this point. Just pushing the ribs roughly back into place will hold the shape of the boat long enough to get the gunwales installed.After the gunwale installation has been completed you have a dilemma of sorts. You need to take the ribs out again, for the last time, to make room for the seats and other interior parts. The gunwales you have just installed have stiffened the boat considerably, but it will still relax somewhat, and lose beam width, if you simply remove the ribs. The easiest way to hold the shape of the boat at this point is to cut two (roughly) 62" 2x4's and jamb them in place from side to side, between the gunwales. This will hold the width of the boat, allowing you to remove the ribs and build the interior parts. Once the front deck, rear seat and rower's seat have been installed, the boat will be stiff enough to hold its own shape. At that point you remove the cross-gunwale braces and prepare for paint. Here is a summary review of events:
    1) tie the ends of the boat together with a rope or wire (details below)2) take out the stations
    3) fillet the inside chine corners4) fiberglass the inside of the boat5) knotch the top outside edges of the trapezoid stations (to makeroom for the inwale)6) push the stations back into the boat, but don't fasten them4) install the inwales 5) install the outwales6) install the temporary cross-gunwale braces7) pull out the rib stations--for the last time 8) proceed with the interior construction 9) paint the boat
Tie the ends of the boat togetherAt this point you are working toward fiberglassing the inside of the boat. To do this you have to remove the three trapezoid rib stations first. However, if you simply remove the ribs at this point, the boat will relax and collapse inward somewhat. The transoms will spread further apart and the gunwales will come together. To prevent this from happening, you have to tie the ends of the boat together. Put a C-clamp at the top-center of each transom. Connect these two C-clamps (from end to end) with a stout rope, or with 2 or 3 lengths of wire. Now you can remove the ribs, and the boat will retain its shape.Fillet the inside cornerst together The next step, after removing the strongback stations, is to fillet the "inside chine". You will also need to fillet both inside corners of the two transom ends. Refer to the filleting review at the beginning of these instructions. After making the fillets, you can wait a day until the fillets are cured, and then proceed to the next step (fiberglassing the bottom) or you can immediately proceed to the next step while the fillets are still soft. If you stop work and let the fillets harden completely, you will have to hand sand the fillets with 80 grit silicon carbide floor surfacing paper before going on to the next step. If you choose to glass over the fillets right away, you will have to wait at least an hour for the fillets kick and stiffen a little. If you try to glass over the fillets too soon, the fresh resin from the new fiberglass will dissolve the resin in the fillets, and the whole thing will collapse into an ugly mess.

Install the final layer of "inside-bottom" fabric

Once these fillets have been made it is time to apply a second layer of "inside-bottom" fabric. This second layer of fabric should lap the chine and "roll up" the side of the boat about 1-1/2". You will have to cut small slits in the fabric at the corners of the transom and at the corners of the stem to keep the 1-1/2" rolled edge from puckering. Now break for the day and let the resin harden.Gunwale installation Inwales The first step in the installation of the gunwales is to knotch the top outside edges of the rib stations (to make room for the inwale) and then to push them back in the boat. You don't have to fasten the ribs. Just push them back into place and let them float there for the next few steps. They help to stiffen up the boat and hold its proper shape, while fitting the gunwales.Each inwale has two compound angles, one at the bow, and one at the stern. To make these joints, measure the distance along the top inside edge of the boat from the top inside edge of the transom to the top inside edge of the stem. This distance should be just a little less than 12 feet, but of course it varies slightly from boat to boat. The general strategy (whenever fitting a difficult piece like this) is to make it a little long, and gradually wear down the ends, until the inwale fits nicely at both ends--without making it too short (cut the damn board three times now, and it's still too short!). Mark the distance along the edge of the inwale stock that will mate with that side of the boat. Then use a bevel square to mark the compound angles at each end. These compound angles each have a horizontal and a vertical component that are not given in the plans. Hold the bevel square right on the ends of the boat, first in the horizontal position and then in the vertical position to determine these angles, and to transfer them directly to the inwale stock. Once you have made the inwales, and hand fitted them, clamp the inwales into place. You can, if you want, screw the inwales in place, in a few spots, with 5/8" screws, screwing in from the outside of the boat. These (optional) screws will be covered by the outwale in the next step.


Once the inwales are in place on both sides, you can proceed with the outwales. Keep in mind that all gunwale tapers, spacer blocks, and oarlock blocks are placed between the outwale and the outside of the boat. Start on either side by screwing an outwale right to the stem. Have a helper hold up the rear end of the outwale while you drive another screw about 16" from the first one. Walk around to the other side of the boat and repeat on the other side. Once both outwales have been started with two screws near the front end, it is time to slip the first tapered gunwale spacer into the triangular slot formed by the junction of the outwale and he side of the boat. The sharp point of the gunwale spacer starts just to the rear of the second gunwale screw. Use a C-clamp to pinch the gunwales tightly around the spacer. Place this C-clamp two inches toward the stern from the fat end of the taper. Then bore a 1/4" hole right through both gunwales and the fat end of the taper. Use a three inch bolt and a nylon-ringed nut (a "nylock" nut) to hold all three pieces together. Then replace the two screws near the stem with 1/4" bolts and nylocks. Then move back toward the stern twelve inches from the fat end of the taper and pinch the gunwales together around one of the rectangular spacer blocks. Bore a hole and fasten the spacer block with a 1/4" bolt and nylock. Keep working backward, putting a spacer block every twelve inches, alternating from one side of the boat to the other, until you get to the first oarlock position, which is the dead middle of the boat, roughly 6' (along the gunwale edge) from either end of the boat. You should have made two 1 1/8"x2.5"x4" oarlock blocks in an earlier step. Before you install the first oarlock block, you'll have to bore a 5/8" vertical hole through it to receive the actual oarlock. After boring the oarlock block, it can be mounted in place between the outwale and the side of the boat. Place the oarlock block in the middle of the boat, 72" from either end, along the gunwale edge. Use two bolts for each oarlock block, on either side of the 5/8" hole. Keep working back toward the stern, placing a gunwale spacer every 12" or so, until you reach the location of the rear gunwale taper. The sharp end of the rear gunwale taper should be placed about six inches forward of the rear end of the boat. Use a hacksaw with a course blade to cut the 1/4" gunwale bolts flush with the tops of the nylocks. Then smooth off the jagged ends of the bolts with a metal file. That's it. The gunwales are installed. Screw down the two cross-gunwale braces and you are ready to remove the strongback stations for the last time. Place one cross-gunwale brace in the middle of the boat, and the other one eighteen inches toward the bow from the middle.

Interior parts: Introduction

So, the next phase of the boat building--making and installing the interior parts--is ready to begin. The plans I have drawn for the interior parts of this boat are as simple as I could make them. If you build the bare-bones interior assembly described in these plans, there will be nothing to stop you from adding storage lockers and other elaborations at a later date. These plans include several full size patterns. Use the patterns to rough-cut their corresponding parts from the scraps of 3/8" plywood that are left over from the bottom panel. Then fiberglass all of these rough cut parts, top and bottom, in advance. Once these interior parts are fiberglassed, it's a simple procedure to hand fit them with a sharp block plane, and then to glue and fillet them into place.

Here is a summary review of events at this stage of the game

    1) fiberglass the inside of the boat 2) install the gunwales 3) install the rear seat 4) install the front deck 5) install the rower's seat gussets, rails, and rail bottoms 6) build and install the rower's seat7) install the front seat pedestal 8) purchase and install the front seat (get a nicely padded front swivel seat) 9) paint the boat Before you begin work on any of the interior parts of the boat, it is important to establish an approximately level reference in the boat. To do this, you must first locate and draw a line across the bottom of the boat, from side to side, that marks the middle of the boat. Station #2 was located on the 60" layout mark. Draw a line across the bottom of the boat that connects the two 60" layout lines. This line marks the middle of the boat. Place a four foot spirit level on the floor of the boat, parallel to the long axis, so the bubble in the middle of the level is directly over the middle line marker that stretches across the floor of the boat. Now shift the boat forward and backward on its cradle as necessary until the bubble in the spirit level reads level. This is approximately how the boat will float in the water when it is unloaded. The front deck, the front seat, the rower's seat, and the rear seat are to be made level to this reference.

Interior parts

There is no one interior design for any boat. In my plans I try to give specific instructions for the simplest, most bare-bones interior layout possible. But I never build a boat the same way twice. I do often stick to one of several well-known hull shapes ( I like to experiment with new hulls too ) but hull experiments are a lot of work. It takes a long time to work out new hull dimensions. Interior parts, on the other hand, can be made in an infinite number of ways. The easiest way to build a rower's seat, for instance, is to make a 1x4 rectangle about 16x45" , cover it with plywood and mount it on semi-triangular cleats glued to the sides of the boat, right below the oarlocks.But you can make a fancy rope cusioned seat too, or maybe make a much narrower seat, if you want, and mount it to much wider left/right dry storage lockers. I have always wanted to build a sliding rower's seat, like the ones found in rowing sculls. That way you could row off your legs, instead of only with your arms and back. I will definitely do that on my next boat. So read the interior parts section below as a way to get familiar with the seat-building process. And then let your own design ideas mold a boat that's just right for you. Bare Bones Seats 1) the rear seat, has a flat, trapezoidal top and a 1x4 front edge, at right angles to the top. This photo, by the way, is of an ancient Buffalo Boat I built in 1983. I recently bought it back from the original owner I built it for. I'll add more photos eventually, when it's restoration is complete. 2) front deck, also built from a flat trapezoidal shape, but without the front lip support, because its front edge gets a curved cutout to make room for standing at the front of the boat. 3) rower's seat gussets. 4)The rower's seat The (above) rower's seat is made from a 1x3 mahogony frame, with ¼" plywood underneath to form the tackle pockets left and right of the roped rower's seat.Two 1x3 x 45" pieces and four 1x3x16" pieces make the basic frame. The front 1x3 gets dished out to make room for your legs. The tackle pockets have a ¼" plywood bottom (shat should be fiberglassed, to prevent checking). The top outside edge of the seat gets a horizontally oriented 1x3 flange that sits on top of the side mounting rails. The following photo shows the mounting brackets.The rope that forms the seat is woven back and forth around a 2x2 piece of fir, that bolts down through the bottom of the seat, so it can be pulled downwards with wing nuts, so to provide a tensioning mechanism for the rope seat. The most important thing to remember about building a rower's seat this way is to wait until after building the side mounting brackets before building the actual seat. This way you can custom fit the seat to fit snugly between the side mounting rails.
    5) front passenger seat pedestal, made from 4 pieces of left over plywood. This pedestal is 12" square and 20" high. You will have to angle the bottom of the pedestal some, so get it to stand straight up when mounted on the curved, rocker-bottom of the boat. The front edge of this 12" square starts 20" back from the front edge of the boat, where the boat bottom meets the front transom. A front standing and casting platform is an optional but luxurious addition.
    6) You'll have to wing the front deck. I don't have a pattern for it. The basic trapezoid is approximately 52" at the back, 27" at the front and 24 deep, from front to back. Make a pattern out of cardboard first, to get the fit, and then transfer the edges to plywood.

Straighten the rear end of the boat. Hand-fit the rear seat

When you take out the strongback stations, the rear end of the boat invariably twists a little. But don't worry about it. You can straighten the rear end of the boat with a pair of C- clamps and a nylon clothes line. Once you have the rear end of the boat pulled back into square, you can install the rear seat. The rear seat will hold the boat square thereafter. To straighten the rear end of the boat, place a C-clamp at the corner of the transom that is twisted furthest away from the front of the boat. Place a second C-clamp on the opposite gunwale about four feet from the transom. Connect these two clamps with a stout string, and pull tight on the string until it pulls the boat back into square. Tie off the string and then proceed to hand fit the rear seat. You should have the main rear seat piece on hand at this point, rough-cut to size and fiberglassed top and bottom. Use a pencil scribe and a sharp block plane to wear away at the edges of the rear seat until it drops down tightly into place. The front corners of the rear seat should contact the sides of the boat at a point approximately 24" from the corners of the transom, and one and a half inches down from the top of the gunwale. The back end of the rear seat should be approximately 5" down from the top of the transom. The seat should also be approximately level. Once you have fitted the rear seat, nail it temporarily in place by driving finish nails into the edges of the seat from the outside of the boat. Don't drive the nails all the way down. Once the main rear seat piece has been fitted, you have to make and fit the rear seat cross-beam. This cross-beam is merely a 1"x4" vertical support that forms a right angle with the front edge of the rear seat. The compound angles at the ends of this cross-beam are not given in the table of angles. You will have to hold a bevel square onto the corners of the rear seat (first in the horizontal position and then in the vertical position) to determine these angles.


You may want to eliminate the rear seat cross-beam, and run a new piece of plywood from the front edge of the rear seat down to the bottom of the boat to form a dry storage locker. You would then cut a hole in the top of the rear seat and make a hinged lid for the locker. Any rear passenger would then sit on the hinged lid. To build a rear dry storage locker that really stays dry, you will have to "raise" up the edges of the locker opening at least a half an inch, and then fashion a contoured lid that fits over the raised edges of the locker opening. Or, instead of a hinged top lid, you can cut a hole in the front of the locker, round off the edges and leave this space open. This makes a convenient place to put life jackets.

Rower's seat assembly

    Once you have completed building and fitting the rear seat parts you can install them now, or set them aside and go on to fitting the "rower's seat assembly," which consists of three parts on each side of the boat the gusset, the gusset rail, and the gusset rail-bottom. The gussets are made from 3/8 or ½" plywood. The rail-bottoms are made from ¼" plywood.The rails are made from 1"x4" boards that are approximately 48" inches long (but start with longer, 60" stock, to allow for fitting). The rail has a square cut at its front end, and a compound angle at the rear end where it meets the side of the boat. The vertical component and the horizontal component of this compound angle are given in the table of angles. The first step in the assembly process is to locate and hand fit the two gussets to the side of the boat. The front edges of both gussets are mounted approximately 2" forward of the middle of the boat.Once the two gussets have been fitted, you can jamb them temporarily in place by clamping a scrap board from one gusset to the other, about twelve inches off the floor of the boat. Then go around to the outside of the boat and drive a finish nail through the side of the boat into the edge of each gusset, but don't drive the nail all the way down. Now that the gussets are in place, it is time to work on the two rails. Cut two sixty inch 1"x4"'s from fir, mahogany, oak, ash, or maple. Use a bevel square to layout and cut the compound angles at the rear ends of the two rails. Your first attempts won't fit well. But you made the rails 12" too long, so you can adjust the bevel square and recut the angles many times, until you get it right. The two gussets have a 1"x4" notch cut into their top inside corners. These notches are there to receive the two rails. Place one of the two rails into the notch in the gusset, and slide the rail backward until the compound angle at the rear end of the rail slides into the side of the boat. Hold a spirit level on the rail to help locate the rear end of the rail. The length of the rail should be level with the top of the rower's seat gusset. Repeat on the other side. At this point it is usually necessary to re-adjust the rear end positions of both rails slightly to insure that both rails are the same length, parallel, and level. Use the block plane to make any necessary fitting adjustments to the rear ends of the rails. Re-mark the two rear end positions of the rails, and screw them temporarily in place with drywall screws that are driven in from the outside of the boat. The exact distance between the two rails is not critical as long they are parallel and level. When you make the rower's seat in a later step, the seat will be custom made to fit tightly between the two rails. Once the two rails have been located and fitted, it is time to fit the two pie shaped "rail-bottom pieces." It's easy to see that these pieces fit into the pie shaped spaces left between the rails and the sides of the boat. These bottom pieces are fastened to the bottoms of the rails. Reach under the rail with one of the two bottom pieces and hold it up onto the bottom of the rail. Scribe the curved edge of the bottom piece where it meets the side of the boat. Use a block plane to hand fit the curved edge. Once the curved edge has been fitted, run a pencil along the edge of the rail (the edge closest to the middle of the boat) to mark the straight edge of the bottom piece. Cut tight to the line. Repeat on the other side. The two rail assemblies form a parallel raceway on which the rower's seat is mounted, and on which it can be adjusted forward and backward as needed for different payload conditions in the boat. The rower's seat gussets

    Preparing the interior parts for installation

    At this point all of the interior parts have been cut, hand fitted, and tacked temporarily in place. Draw a pencil line around each part to mark its location on the hull of the boat, and then remove these parts and set them aside. The next step is to glue the rear seat to the rear seat cross-beam, and the front deck to the front deck cross-beam. After gluing the front deck and the rear seat to their corresponding cross-beams, glue the four rail bottoms to their respective seat rails, and set these pieces aside to cure for a few hours. Once the glue joints have hardened sufficiently, these parts are ready to be installed.

    Part Four: Installing interior parts

    Cutting and fitting the interior parts is the hard part of the job. Once all the rear seat, front deck and rower's seat gusset parts have been cut, fitted and tacked temporarily in place, you can glue them in place with thickened resin and a few strategically placed nails or screws. After the resin has hardened you can fillet the corners and then use fiberglass tape to lock these parts securely and permanently to the side of the boat. Install the rear seat first. Remember that the two C-clamps and the clothes line are still in place holding the rear end of the boat square. You won't be able to remove these clamps until the rear seat has been successfully installed. To install the rear seat, wet out the mating surfaces, and then spread a second batch of resin, thickened with microfibers, onto the edges of the seat itself. Use drywall screws driven in from the outside of the boat hold the seat in place while the glue cures. Don't get upset if a few of these screws miss their mark. All of these screws will be removed, and the screw holes patched at a later date. Install the front deck in the same manner, holding the parts temporarily in place with drywall screws until the glue cures. Glue the seat gussets in place with the help of temporary drywall screws, and then the rail and rail-bottom assemblies.

    Filleting the interior parts

    Once the resin has cured, pull all the screws and putty the holes. Then fillet the interior parts into place. Fillet the "underside-edges" of the rear seat, the front deck and the rail- bottoms first. Use a particularly stiff filleting mixture for these "underside" fillets. Then fillet the top edges of the interior parts. Use a slightly thinner filleting mixture for the "top-side" fillets.

    Make the seats

    The (above) roped rower's seat frame is fourteen inches wide, and approximately 38.5" long. The actual length of the rower's seat is determined by the distance between the rower's seat rails. So you have to install the rails first, and then measure. The frame is a simple rectangle, with two intermediate crosspieces added in the middle of the frame for extra strength. Butt joints glued and screwed are strong enough. Dadoed joints are stronger, but not absolutely necessary. The outside edges of the roped rower's seat get two 1x3, horizontally oriented "wings" screwed on top, that form a lip that fits over top of the rower's seat rails.

    Making the Hole for the Boat Plug

    Most boat plugs consist of a rubber cylinder that can be expanded slightly by some mechanical means. Usually, a one inch rubber cylinder is expanded or contracted by twisting a metal "T" handle, or by lifting a metal cam lever. A one inch hole can be drilled right through the bottom of the boat to receive the plug. The best location for this hole is at a bottom corner of the transom. However, any plug that is simply stuck into a hole in the 3/8" bottom of the boat will stick out past the outside surface of the boat, where is subject to damage from passing rocks. The best solution is to increase the thickness of the boat at the bottom corner of the transom before boring the plug hole. To do this, cut an equilateral triangle from plywood or from a scrap of Formica that is approximately three inches on a side. Use a wood rasp to custom fit the edges of this triangle so it can be fitted over the triangular corner formed by the junction of the chine and a bottom corner of the transom. Mix up about a cup-full of very thick resin. Mix the resin with micro balloons and microfibers until it reaches the consistency of peanut butter. Then trowel this thickened mixture into a bottom corner of the transom. Then place the hand-fitted triangle over the cup-sized glob of thickened resin to make flat surface over a thick, solid mass of resin. Clean up any squeeze outs. Once the resin has hardened, bore a one inch hole through the bottom edge of the flat triangle, downwards and outwards, and out through the chine to the outside of the boat. The bottom edge of the one inch hole should be flush with the bottom of the boat. Coat the inside edges of the hole with resin. This completes the drain hole for a one inch, expandable plug.

    Preparing the boat for paint

    Remove the two adjustable seats, and sand down any glue bumps or drips. Fill any dents with resin and micro balloons. Spread finish coats of resin (sanding between coats) as necessary to produce a clean, smooth finish. Then paint the boat. Follow the manufacturers instructions for applying the paint. The best looking paint jobs are achieved with a spray-gun and standard auto-BODY techniques, but excellent results can be achieved with a good china bristle brush and ordinary oil based paint.

    Wrapping Oars

    Use 9' ash or spruce oars. I prefer ash.

    Use rubber oarlock stoppers to hold the oars about two inches apart in the middle of the boat so you don't smash your thumbs together when rowing. Sand off any varnish from the shank of the oar on either side of the rubber stopper. Wet out the sanded area with unthickened resin. Wait about thirty minutes, and then brush on a fresh coat of fresh resin that has been slightly thickened with microfibers. Wrap 3/16" nylon rope around the oars on either side of the stopper, pulling the wraps tightly into the thickened resin on the shanks of the oars. Wrap four or five wraps on the handle side of the oarlock stopper. Tack the ends of the rope down with carpet tacks. Wind many more wraps around the oar on the blade-end of the stopper. Keep winding around the oar until a minimum of twelve inches of rope wraps are built up on the blade side of the stopper. Tack the ends down with carpet tacks. Repeat on the other oar. Now it's time to load up the boat and take some friends for a ride!