My Backyard Boats:

The Flats Rat building log -- 2nd boat: single file

 

 

 

  

    24 September 03:After building a Flats Rat paddle boat, I decided that I wanted one for myself.

    I gave the first one to my wife, the Reverend, as a surprise. After trying her boat, I realized that I wanted to join in the fun. So I began again to build, and this time I kept notes as I went but did not post anything on my website. Now I’m going to post the entire log as one big file.

    In 14 consecutive days of work, with a total of 52.5 hours of building time, and a modest $122 in costs,I had a Flats Rat ready for the water. We launched two days later, and it was wonderful.

    The Flats Rat is one of a number of boats that are variations on a single-sheet, vee-bottom punt called the Mouse.

    The plans are free for download from the Internet. The designer, Gavin Atkin, has released the design to the public on the model of the Open Source movement in software development.

    Flats Rat is a kayak-like boat and is capable of all-out speed of 3.2 mph.

    Total cost: $122.

   Total time: 52.5 hours over two weeks

  

    24 August 03: I got two sheets of lauan and two 2x10x8-foot planks of hem fir from the friendly local home store. I had thought that I was picking through a pile of spruce and only found my error when loading the planks into the truck.

    The ply is good, with a reddish face I like for the interior and a lighter A-face for the exterior. The wisdom of using the A side in and the B-side out doesn’t get the nod with this lauan when I am going to be finishing the boat bright. The reddish face is far prettier and I like to see it on the inside of the boat. Also, putting the A-face out makes the painting go even quicker.

    As with the last sheets of lauan that I got, I again noticed a strong aroma of bananas – the mystery wood in the core layer, I suspect. It sure is different than the pine smell that I like but is pleasant in its own way. Suggests Banana Boat as a boat name ... . At any rate, it smells better than the hem fir, which has an unpleasant aroma when freshly cut.

    I’m going to rip the hem fir and see if the grain is good. The planks are fine, with only a few, big knots. At $6 each, the two hem fir planks were a bargain – if hem fir strips will bend without breaking, that is.

    I recall a reference to hem fir on the Internet, I think, as being a poor boat wood, but that was one comment. I’ll decide for myself. Building boats is really just solving design and materials questions, I believe, so my mistake in selection really wasn't’t a mistake. Something like an unexpected opportunity. I’ll also do a word search on hem fir to see what’s out there. Here is a link to a wood products industry site, which accounts for the lack of any mention of hem fir’s aroma. My Dad would have called it piss fir instead of hem fir. That was the usual nickname in the woods for white fir. Dad was a logging truck driver.

    The thing that tipped me off that I had not gotten the spruce that I had intended to get was seeing Tillamook stamped on the planks. Been there. Tillamook is in a prime Douglas fir zone, on the northern Oregon coast. I immediately had a mind picture of a sawmill that I drove by once in the Tillamook River Valley not too far from the town and the cheese factory of the same name. This mill was at a crossroads, where the coast road turned inland after miles and miles of tracing the seaward edge of the Tillamook Burn, an immense forest fire disaster caused by logging practices in the 1930s.

    My dictionary sez that hemlock fir is a term for spruce – genus Tsuga, family Pinaceae. The industry website says hem fir is a marketing category that includes five woods including silver fir and white fir that share certain characteristics. I noticed that the pieces that I cut were notably light, flexible, and strong. But that smell ... .

     After being around the smell for a while, I realized that it also reminded me of the times that my dad would take me to the mills or into the woods in his logging truck.

    When I had laid out the sides of the Flats Rat, I decided to sandwich the two sheets and cut both sides in one pass. I used the circular saw set for a shallow cut. The cut got away from me at one end, so I had to re-fair the line, losing a fat inch of depth. The curve looks fair, though, so I didn’t throw out the cut sides and start over.

    I’m curious to see if this boat handles any differently because of this error and fix. I figure that I’m close to prototype work here, so I’m going with the re-faired curve. The error is far greater than I would accept if following plans, especially on a bigger and more expensive boat, but establishing a fair curve is still fundamental to any lofting-type work such as this on a boat.

    I made the mistake because I’m still a novice, really, at using a circular saw to make a cut like this. I’ve been using the circular saw instead of the saber saw for cutting ply, because the cuts, though harder to control, are smoother and quicker with the circular saw. Just watch for kickback; the durned things kick back with almost no provocation.

    25 August 03: I’ve decided to cut the bow and stern transoms and the forward and aft bulkheads to fit the sides as adjusted for my error in cutting the bottom curve. If I take the measurements from the side pieces as cut, which I’ve scribed for the bulkhead placements, I should get away with a minimum of planing, or adding shims.

    I used the plans that are available from www.shortypen.com to have a reference point for the placement of bulkheads, but I moved them in slightly to partially compensate for the loss of the inch in depth, and to bring the center of balance forward some, too.

  I marked one vertical line and indicated the other edges with broken lines.

    Costs: plywood (two sheets of 1/4-inch lauan underlayment, which is actually closer to 3/16ths of an inch thick, or 5 mm) – $20; hem fir – $6; boat nails – $6.

    Time spent so far: 3 hours.

    I marked the transoms and bulkheads on the A-face of the plywood because it’s lighter than the ruddy red B-face. You use the factory edge as a reference point for drawing lines when cutting out. Also, I marked bow and stern because the ends were within 3/4 of an inch of one another.

    I put all the scribe lines on the inside of the side pieces. They won’t show much if at all because of the air chamber spaces. I was careful to account for the width of the bulkheads – 1/4 inch for the ply plus 3/4 inch for the frame sticks.

    I left about a 1/4 inch between each plywood piece as I laid them out, to account for the saw kerf and inevitable tearing. It’s always best to leave a margin, but not too much. Many times the plywood is allocated with the barest minimum of slop. If you make small errors, you can find yourself with too little plywood to make all the pieces that the plans call for.

    I also attended to the grain direction, because I know from bitter personal experience how easy it is to lay out pieces wrong and end up buying an extra sheet of plywood to compensate. I like to use a wood straight-edge, a rafter square, and a dead-accurate engineer’s square that I paid about $20 for.

    If I can’t reference a scribed line from a factory edge on the plywood, I use the steel tape measure but not from the end. I either line up from the 1-inch mark or the 10-inch mark, etc., to get accuracy. Just double-check your marks; it’s easy to forget to calculate correctly in these cases.

Measuring trick: Use the 10-inch mark and read it as "1" to get an accurate measurement by avoiding the hook on the end of the tape measure, which can throw you off if you try to line up a mark like this.

 

    I cut the scribed plywood out by eye with the circular saw, leaving a margin. Then I used the bandsaw to cut each piece out, leaving the lines as reference points for placement of the frame sticks. I can either trim with a block plane or belt sander, or I can cut and nail/glue the wood frame strips to the line and sand after, which makes everything easier to assemble and more accurate, too.

    I’m still finding my way with the bandsaw, so cutting close to the line gives me a margin for error, since the blade wanders some. And at the same time, I get practice time on the bandsaw, which was a birthday present a few months ago.

    26 August 03: I set up a thin-kerf table saw blade that I got from Dave Carnell. The blade has carbine tips but only cuts a kerf 1/6 of an inch wide instead of the usual 1/8 of an inch that regular carbide blades cut. The first cut in the hem fir smelled like Dad’s piss fir. The grain is good, though. I got 11 strips of 3/4 by 1 ½ inches by 8 feet from the 1x10x8-foot plank that I cut.

    These ripped pieces will be the external chines, the gunwales, and the frame stick stock for the transoms and bulkheads. I’ll leave the frame sticks that will be beveled the full width, and I’ll leave the sticks that won’t be beveled at 3/4 by 1 ½ because the wood is light and the extra won’t make much difference.

    The chines will be 3/4 by 1 inch and the gunwales will be 5/8 inch by 1 1/4 inch. Make that 3/4 by 3/4 for the chines. I discovered that the bigger piece can’t make the bend. I also can cut so the grain is helping make the bend – using flat grain instead of vertical grain. A slash or flat grain board yields vertical grain ripped boards, which are generally superior except when the vertical grain inhibits bending to a curve.

    Cutting to 3/4 by 3/4 yields an off-cut of 3/4 by 11/16s. There are uses for these off-cuts, such as laminating paddle blanks. The gunwales are cut to 5/8 inch to save weight higher up in the boat (probably more of an illusion than a savings, but it also looks less bulky on a boat of this size).

Chines and gunwales ripped to size from hem fir.

 

    Some of the ripped hem fir is warping already, which is actually preferable, because it helps make the curves when the boards are already bending in the right direction before being put into place.

     Time: 1 ½ hours to rip the hem fir.

    After I stopped for the night last night, I realized that I had not cut the bevel for the bow transom in the plywood sides, so I did that. I sandwiched the sides together and picked up the angle of the bevel from the plans, using a sliding bevel gauge.

   I’ll have to cut a new bow transom, because I picked up the wrong dimension when I forget to take the bevel into account. I made sure that there was enough plywood left to cut a new bow transom and still have enough left for the decks.

    I decided to true up the bow and stern transom pieces so that the A-sides will be on the exterior of the hull. The bulkheads are scribed on the A side, so I can use the other method of nailing the frame pieces to the scribed lines, but I decided to true them up, as well.

    The belt sander made it a quick job. The block plane works well, too, but you have to watch for tear-out on the corners.

    Time: 1 hour.

    The next step was cutting the bevels for the frame sticks. The bow and stern transoms have beveled sticks on the sides and the bottom. The bulkheads also have bevels on the sides and bottom.

    You need to take care to cut the bevels in the proper directions. I use the table saw to rip cut the bevels. Since I had to change the bottom curve to fix my cutting error, I picked up those bevels from the side pieces with the sliding bevel gauge.

    I generally cut the top and bottom frame pieces full width and piece in the sides to fit. By cutting long, I can trim with the Japanese pull saw to make it nice all around. I tried to orient the wood grain so that any cupping would bring the stick closer to the plywood instead of opening a gap. This takes some effort but is a good thing to do.

    An alternative way to cut the frame bevels is to nail and glue up, then cut to lines drawn with a straight-edge. The side bevel needs to be cut before the sides are joined to the transoms and bulkheads, but the top and bottom bevels can be cut after. Or you can use a circular saw or handsaw. I like the table saw for this job.

    If you make errors, you can usually fix them. Think it through first, and visualize the boat’s various angles. Study the plans. Then sin boldly! It’s your boat. Set your own standards.

Glue and boat nails attach beveled wood strips to the bow transom. Bevels were cut before the piece was assembled. The Japanese pull saw will make short work of the excess on the top and bottom strips.

 

    I used 3/4-inch silicone bronze ringed boat nails and Elmer’s Probond glue to assemble the transoms and bulkheads. I used a two-one-two pattern in placing the nails. The glue is waterproof and nontoxic – and much cheaper than epoxy – $52 per gallon vs. $12 per gallon.

    I put epoxy over the joints and seams, in and out, if I want to increase the waterproofing, though on this boat I’m not planning to use any epoxy.

    Fifty hours of work and $100, more or less, will give me another such boat, so I’m opting for no epoxy at this point. It’s a test of the ability of the Elmer’s glue, too. (Note from later: I did use epoxy on the interior joints).

    Since the top frame sticks for the two bulkheads don’t take bevels, I nailed and glued those pieces before cutting the bevels for the side and bottom pieces. That gave me a substantial and accurate baseline. I left the top pieces full width for a touch of extra strength for the decks.

    In placing the nails, I tried to anticipate the possibility that some trimming may be necessary. I left a bit of extra space on the top sticks because if I attach the sides to the transoms and bulkheads right side up, any extra will stand proud of the gunwale lines. Bronze boat nails sand well but can nick tool edges. I usually have to sand some nails to get fair lines. We’ll see how it goes this time.

    I didn’t use any clamps because the boat nails are spaced closely. And clamps are a pain sometimes and leave dimple marks if you don’t fiddle with wood blocks to protect your work from the clamps’ tendency to leave depressions and dimples. Sometimes I just clamp and deal with the dimples later.

    I put the bottom frame sticks on wrong on the aft bulkhead, so I’ll have to re-cut it after the sides are attached. Didn’t check twice.

    Time: 4 hours to finish the transoms and bulkheads.

Centerline marked clearly on table that will be the strongback.

 

    27 August 03: I set up my 2-foot by 5-foot plywood-top workbench as a strong back. First I drew a centerline, then a line for a batten to hold the aft bulkhead true and untwisted. I remembered to make centerlines on the transoms and bulkheads.

    I decided to build the hull upside down, so that the strong back will maintain trueness while I bend on the chines and bottom. I tried to glue as I went but had to switch to dry-fitting first with deck screws, which work perfectly for dry-fitting because they are self-tapping. There is almost never a need to pre-drill for the deck screws except for douglas fir, or at the ends of boards. Be careful not to overdrive the deck screws if you use an electric driver or drill with screw bit. This will split the wood.

    I used some cord to pull the sides in so that I could dry-fit the forward bulkhead. Then I nailed the aft bulkhead to the wood crosspiece that I cut to 3/4 by 24 inches. Then I nailed the forward bulkhead to the table at the centerline to get a pivot point, and nailed a crosspiece to the table and the bulkhead, lining up the centerlines and positioning the crosspiece with the square.

Light cord makes a windlass to pull in the sides at the bow and hold them in place while I attach the bow transom.

 

    Since I was at the bow, I dry-fit the bow transom first. I attach the side to the inside of the bow piece, which left both plywood edges exposed. I’ll treat them with epoxy or glue then round them. If I were to go first class, I’d epoxy putty and fiberglass tape all the outside seams.

    After I glue and nail what I’ve dry-fit, I’ll attach a wood batten at the centerline, to make sure the transoms stay true and untwisted, and to make sure that I have as much bracing as I’ll need when I bend on the external chines.

    Time: 2 hours.

    I pulled the boat out of line when I attached the batten, so I pulled the screws in the bulkheads and re-trued the bulkheads vertically, then nailed them. The boat is within 1/32 of true now. I can live with that!

    I’ll glue the dry-fit stuff tomorrow when I’m rested.

    28 August 03: I backed off the deck screws on the bow and the forward bulkhead to glue and nail them. Then the other two on the same side, then the same drill for the other side.

After assembling the hull with deck screws, I backed off the screws one joint at a time and glue and nailed.

 

    Double-check the alignment. Deck screws can tap new holes without much warning. Use index pencil marks, and leave the screw points out enough to find the proper holes. You get used to feeling the tip find the hole as you slide the pieces.

    Use paper towels to wipe up excess glue – and use a lot of glue. Be mindful that glue will affect the appearance of wood finished bright, even with varnish alone. The glue can cause a mottled appearance. If it is necessary, you can use a wet paper towel to remove the glue.

    Since the exterior of this hull is to be painted, I drew a line to show where to nail. I used 3/4 inch boat nails on 3/4-inch centers. The wood behind is soft, and the glue needs help since I’m not clamping. Boat nails have the holding power of screws because of the rings on the shank. The deck screws will come out when the glue sets. I’ll putty the holes they leave with glue thickened with wood flour.

    I glued and clamped a shim to the aft bulkhead – no nails, though. I’ll plane it flush with the rest of the frames to prep for the bottom piece of plywood.

    Time: 1 ½ hours.

    Costs: $10 for varnish and $6 for nails.

External chines clamped in place.

 

    29 August 03: The next step – bend on and glue/nail the external chines. I chose to use external chines because they require no notching of frames, unlike internal chines. In a displacement hull, any water flow problems are negligible. And some say that external chines actually improve water flow past the hull.

    I used more of the hem fir for the chines, 3/4 by 3/4, which let me use the grain direction with the greater amount of flex. The first one went on easily, in fact easier than the high-grade pine chines on the first Flats Rat that I built. The idea is to bend on both chines to minimize forces that lead to hull twist. When you glue and nail, you remove clamps equally from each side and reapply them as equally as possible, too.

    I like to install half of a chine at a time, and to this end I double-clamp at the midpoint, and I use a pencil mark to line up the side and chine at each spot where a clamp goes. Careful marking of carefully place clamps will ensure that there are no gaps between the chine and the plywood. I have about 15 clamps, and I usually wish that I had a few more. I used 3/4-inch boat nails to secure the chines to the plywood.

    The fair curve of the clamped chines revealed a hump of plywood that was out of fairness on each side aft. I planed the sides to match the chines. Also, I placed the chines to favor the line they curved to rather than the curve cut into the plywood. This is a second check of fairness.

    I used two hammers to drive the boat nails – one to hit with and one on the other side to absorb the blows and protect the wood from flexing and possibly splintering. Remember to run a pencil along the chines to show where the glues goes on.

    I quickly switched to using a pair of pliers to hold the nails while giving the first taps with the hammer. That speeded up the job, and saved my fingers.

    Time: 2 ½ hours.

    Cost: Epoxy at $10.

Straight-edge board shows high spot on bulkhead.

 

    The next job was to use the belt sander to fair up the chines and the bottoms of the transoms and bulkheads. I used a straight board to make sure that all was true in preparation for the bottom piece of plywood.

    I don’t bother with leveling my building forms or boats, because in 30 years of woodworking paired with a certain amount of moving about, I never have had a wood shop with a level floor. I make sure that the boat is true to itself from side to side. I use a straight board to eyeball surfaces for fairness, and I use various tools such as sanders and hand planes to br9ing surfaces into readiness for plywood sheathing.

    My eyeball is accurate to 1/64th of an inch.

    Time: 1 ½ hours for fairing.

    There is a point in any boatbuilding project where you must decide what angle to cut various pieces such as the ends of the chines and gunwales. For the first Flats Rat that I built, I chose 45-degree angles for these cuts. I’ll use the same angle here.

    These angles are actually compound angles. You follow the edges of plywood as a guide while cutting to the 45-degree angle scribed on the tops of the pieces.

Checking the fairing of the chines in preparation for scribing, cutting, and nailing and gluing the bottom onto the hull.

 

    30 August 03: The bottom of the hull:

  • Scribe centerlines on each transom and bulkhead if sanded off during the fairing process.
  • Scribe centerline on plywood to be used for the bottom of the hull.
  • Clamp plywood to chines and scribe a cutting line around the perimeter.
  • Cut the plywood, staying about 1/8 of an inch outside the scribed line.
  • Remove tools from the space inside the hull before attaching the bottom.
  • Clamp the plywood and scribe a line for nailing. This is especially important if you leave a generous portion outside the scribed line and if your margin is unevenly thick and thin. Rather than continually guessing where the nails should be placed, you always know where they go. You can make a special scribing guide from a scrap of plywood. Basically, you cut a groove about 1/4 of an inch wide, leaving a piece on each side of the groove. One side is cut to ride on the edge of the chine and the other side is cut to the desired nail line, which bisects the chine width. You can eyeball, but you’ll get a few nails that miss the mark and stick out inside the hull along the side seam. I borrowed this trick from designers of the Weekend Skiff.
  • Reach in and wipe excess glue from the sides of the boat, and wipe the exterior, too.
  • Start nailing at the midpoint on each side to tack the ply down without humps or gaps. When you get near the end, nail the end from the center out to avoid humps or gaps.

This simple guide sets an accurate nailing line on an irregular edge. You only have half of 3/4 of an inch to play with when nailing into the chine.

 

    Remember to scribe a line to guide the nails that go into the bottom of the bulkheads.

    I decided to take up the hull so I could get all the excess glue wiped up. This saves a lot of work in sanding later. I had to pry the boat from the strongback because I couldn’t get at the nails that I had driven to attach the frames to the strongback. Something to watch out for.

     Luckily, I used a total of just five finishing nails so the prying went well. I had two spots of damage on the forward bulkhead, but I glued the slivers back in place.

    By turning over the hull now, I was able to re-attach the wood batten on the centerline to fight twist now that the hull was completed and removed from the strongback. After I attach the gunwales, I’ll flip the hull again so that I can attach the two 3/4 by 3/4 keel strips, which I’m trying instead of a skeg, to make for better tracking while keeping the bottom from oil-canning when one gets into the boat. The Reverend’s boat oil-cans; this one won’t.

Those glue runs cleaned up with a paper towel. Left to dry, they would have required scrapping and sanding, and still the finish would have been ruined. Pic also shows the slight damage on the top of the bulkhead from prying the hull off of the strongback.

 

    Time: 2 hours.

    Costs: $10 for screws and hardware.

    The gunwales: I used 5/8- by 1 1/4-inch hem fir for the gunwales. I clamped on the strips equally from side to side to fight hull twist. I scribed a glue line and nailed and glued the gunwales with 3/4-inch boat nails.

    I made a pencil index mark at each clamp spot to make assembly easier when I do the gluing and nailing and to avoid gaps between the strips and the plywood sides. After assembly, I cut the ends of the gunwales to the same compound angle as the chines.

    Keel strips: I scribed a line 5 inches on each side of the centerline on the bottom of the hull. The 3/4 by 3/4 keel strips go to the outside of these lines. The combings for the hatch covers will be set on the same measurements.

    Since the keel strips are 3/4 by 3/4, I could choose the side to bend. The easier bend came from using slash grain instead of vertical grain.

Gunwale bend in place and clamped.

 

    General note: When attaching the chines, gunwales, and keel strips, I was careful to dry-fit the pieces. The boat is 8 feet long, and the various strips are the same length. Placement is critical; I had about an inch to play with.

    For the keel strips, I drilled holes every 6 inches through the hull. I was careful to drill on the outside of the scribed lines. After driving deck screws through pilot holes into the transoms and the bulkheads, I flipped the hull and drove 3/4-inch screws into the keel strips to pull the strips and the hull together. I wiped off the excess glue before flipping the hull.

    Time: 1 ½ hours.

    31 August 03: I took the deck screws out of the keel strips on the bottom side and replaced them with steel screws bedded in Elmer’s Glue to give the wood some protection from moisture where the screws have compromised the wood.

    I found some cash, so I’m able to use epoxy thickened with wood flour to seal the seam on the interior of the hull. The first thing to do is use masking tape to outline the places where I want the epoxy confined to. Then I cover the rest of the interior with newspaper. This makes a good bead of epoxy with no mess or fuss – no sanding of glops that drip off the brush, for example. If I have it – and I do – I prefer 3M blue masking tape to define the epoxy beads. Duct tape will work, too.

    The prep time is surprising but what one avoids is runs, ripples, and globs of epoxy that can’t be removed without damaging the face of the plywood and running into hours of sanding, in the worst case.

Keel strips in place. Line of nails holds hull to bulkhead.

 

    Time for prep: 2 hours.

    Time to apply epoxy: 1 hour.

    This is the third boat that I’ve finished with epoxy on the interior seams. I’m getting better with each repetition.

    This one went extra well.

    Better than ever.

    I used about a pint of epoxy and 1/4 pound of wood flour. I like the epoxy to be thick because of the vertical surfaces that are involved, especially, but also because epoxy runs thin without some sort of thickening agent.

    I have used microballoons (expensive and staining) and silica (expensive). Now I use only wood flour, which is cheap and effective.

Blue masking tape defines the size of the epoxy bead that will seal the hull on the inside.

 

    After apply masking tape, I cover the rest of the interior with newspaper. This catches all the drips and mistakes that occur during the job.

    I used a 2-inch disposable brush to paint unthickened epoxy onto the seams before troweling on thickened epoxy with a tongue depressor. The corners are the hardest to get right, but I find that it’s better not to overwork the application. I just apply a lot and smooth it out once.

    1 September 03: To get ready for the decks, I used a belt sander to make the tops of the transoms, bulkheads, and gunwales ready for the decks. Then I ripped the remaining plywood into strips of the proper widths plus a little for the decks and hatch covers.

    I lined up the square edges of the plywood with the bulkheads and scribed the other edges. First I marked an opening 10 inches wide on the transoms and bulkheads.

    The side combing pieces are attached to the decks before the decks are glued and nailed to the hull. Also these combing pieces are half-lapped on the ends to accept the transversal combing pieces. And because of the decks, a shim of the same 1/4-inch plywood is nailed between the deck pieces on top of the transoms and bulkheads. These pieces help stiffen the hull at the ends. The combings are 3/4 by 3/4. I used hem fir and spruce.

Side combing pieces lapped and glued and nailed in place. At right in pic, you can see the shim that levels the space on top of the bow transom between the deck pieces.

 

    I cut the laps on the table saw by setting the blade for the proper depth of cut and using the rip fence to define the length of the lap. For example, to make a lap 3/8 by 3/4, I set the blade to cut 3/8 deep and positioned the rip fence 3/4 inch away from the blade. The first cut defines the joint; the next cuts remove the rest of the wood. You can cut in both directions; just be careful. I used a piece of wood off-cut for the shims because it was already the right dimensions.

    Time: 4 hours.

    Costs: $5 for boat nails.

    Hatch covers: I used off-cuts of 3/4 by 11/16s hem fir with half-lap joints on the lateral pieces of the locating cleats. The locating cleats go inside the combing pieces.

    To put the cleats in the proper position, I scribed centerlines on the cleats, the plywood hatch cover pieces of plywood, and the transversal combing pieces. After cutting the lap joints and all the pieces to fit, I nailed the cleats into a rectangle and checked the fit with the combing pieces. Then I drilled a holes through the plywood and the two transversal cleats, and screwed them together but without any glue. After checking the fit, I glued and nailed the cleats to the plywood.

    I made a saw kerf in each hatch cover and the combings as an indexing mark. I can tell at a glance which way a hatch cover goes by locating the kerf.

Bow combings in place. Hatch cover locating cleats at left and hatch cover at right are ready for assembly with screws and nails.

 

    Time: 2 hours.

    2 September 03: The first job was to nail and glue the cleats to the hatch covers. I used brass screws to dry fit the two. I applied glue and reset the screws, after running a countersink bit to make the screw heads flush. The brass screws, though pretty, are useless as screws. They did plug the holes, though, and boat nails supplemented the screws nicely.

    Time: 1 hour.

    Costs: 2x6x12-foot spruce at $6 for paddle blanks and 15 feet of 3/16-inch shock cord at $7 for the hatch covers.

    With the completion of the hatch covers, the hull done, too. What remains is to sand the plywood flush, finish-sand, do any sealing of seams or exposed plywood edges, fill any screw holes made by temporary use of deck screws, and install the eyebolts and shock cords to seal the hatch covers; make double paddles for both boats; and prime and paint, and varnish.

    I want to be done in a week so we can have an outing in our little paddle boats. I’m on track. I got the 3/16-inch black shock cord and a beauty of a 2x6 plank of spruce for the paddle blanks this morning.

Ends of gunwale and chine have been cut to 45-degree angles.

 

    The final sanding presents opportunities to decide how to fair edges and seams. It is a hands-on bonding with the boat. I use 60-grit papers for my belt sander and random-orbit sander. This gives a good level of finish as well as an aggressive capability.

    I sometimes use finer grits for hand-sanding between paint coats, or I just grab a well-worn piece of 60-grit paper.

    For nasty hand-sanding, such as messy epoxy squeeze-out, runs, or ripples, I have three large sheets of 20-grit, 36-grit, and 80 grip heavy-duty papers. The 20-grit cuts like a steel file, the 36-grit is a workhorse grade, and the 80-grit is so long-lasting that it seems to cut like a much coarser paper.

    I have large sheets of these three grits that were left over from a floor-sanding job I did years ago.

    Time: 2 ½ hours.

    Since I’m not putting fiberglass tape on the exterior seams, I’ve decided to sand the chine edge only enough to remove the knife edge. I’ll be interested in whether a square chine edge affects the flow of water around the hull. (Note from later: It doesn’t). To maintain the visual balance, I sanded the gunwales the same way, removing just the knife edge; I’ve seen this described as taking off the curse.

I brushed on epoxy on the gunwales, chines edges, bow, stern, decks, and interior of the hull.

 

    I decided to paint some epoxy on the outside seams. I moved the boat outside to the garage, with the Reverend’s help. I could have done it alone, and did with the first Flats Rat, but I decided to give my tendons a break and to avoid the dings that happen when I go it alone up the stairs from the basement with a finished project.

    It’s crowded in the garage bay that I use for building. There are three boats in a space 8 feet by 16 feet.

    The epoxy went on well. I had enough mixed to paint the decks and gunwales, too.

    Time: 1 ½ hours.

    Cost: $5 for epoxy.

     3 September 03: I had a little bit of Interlux white primer and thought that it was enough for the whole boat.

     By the time that I got done with the job, I felt like I was trying to feed the 5,000 with one pat of butter spread very, very, very thin.

    I think that I got a fairly uniform coat, though, and I did use up all the extra primer.

Primer coat used up every bit that was left over from the last boat project.

 

    A boat like this is fun because you can do whole jobs with stuff left over from bigger projects. I paid special attention to the cracks along the chines, gunwales, and keel strips. It will take two coats of green Interlux paint to finish the job.

    The epoxy that I applied last night was well-behaved. I didn’t have any significant spots to sand.

    I first gave all the epoxied surfaces a light sanding so that the primer would stick.

    I’m going to flip the boat and varnish the interior and the forward and aft air chambers. I’m going to leave the 3M blue masking tape on between coats of green if I can. I do worry about it sticking too well, though. I seem to want to rush things and cut corners when I get to the painting and varnishing stage.

    I put some blue masking tape on the keel strips before flipping the hull. I did re-decide on the blue tape. I took off what was there and put on new tape so that I could varnish everything that I wanted to varnish rather than leaving the tape on from the painting.

    Time: 3 ½ hours.

    Cost: $6 for varnish and $5 for primer.

    I think that tomorrow I’ll put on the first coat of green paint and no varnish. The second coat of varnish can go on whenever; the paint would benefit from some time for curing. I just remembered that I forgot to bring the hatch covers outside from the basement .... . Stuff happens.

The paddle blank takes form. This one had a lot of curve in the shaft.

 

    Double paddle: I’m making two double paddles.

    The one that I made for the Reverend’s Flats Rat broke on our way home from our vacation in August. I didn’t tie it down, and it bounced on the highway and broke.

    I used the broken paddle to make a template from plywood to use when scribing the ends of the paddle blanks to set the arc of the blades. I designed this double paddle by coping the arc from Mac McCarthy’s Wee Lassie double paddle and from Jim Michalak’s double paddle design for his Toto kayak design.

    From Jim I copied the narrow-blade approach; from Mac I copied the 3/4- by 1 ½-inch blank to accommodate an arced blade. Jim specified a plywood blade; Mac specifies 3/4 by 1 ½ sticks cut to the proper arc and laminated to a shaft blank.

    I bought a beautiful 2x6x12-foot spruce plank that I ripped into 7/8- by 1 ½-inch boards. I three pieces long enough to yield Select grade blanks 8 ½ feet long. I make the blanks long by kayak standards because the Flats Rat has more freeboard than most traditional kayaks and a heck of a lot more beam – 32 inches plus vs. 22 inches or so.

    I cut the first blank on the bandsaw and used it to scribe the arc on plywood for the template. I’ll also use the bandsaw to cut the blank to 3/4 by 3/4 or thereabouts. If you don’t have a bandsaw, you can use a saber saw and some kind of sander – belt or random orbit.

Plywood blade is bent in place and glued.

 

    I used a piece of 1x12 pine to cut a template for the blades. I wanted something that wasn’t cupped.
I used the bandsaw to cut the shaft blank to 3/4 by 3/4. The blank has taken on an interesting but possibly helpful warp. I figure that a stick that takes a bend will be stable. The only way to control this would be to cut sticks that could be laminated.

    I like surprises, too, though, and I’ll go with this blank and see how it comes out.

    If all this sounds like a big pain, you can always buy a double paddle or make a simple one form 1-inch fir closet rod stock and a plywood blade. It’s your paddle. Got $75? Mine cost $10.

    I checked the paddle blank and the plywood blade. The blade can make the bend.

     Time: 2 ½ hours so far on the paddle.

    4 September 03: I put a second coat of varnish and a first coat of green Interlux Brightside on the boat. The varnish is disappearing rapidly, since it is both seal coat and top coat.

    The green paint went on unevenly, as is the nature of this green paint. I have enough left over for a second coat, which will fix the unevenness. The paint is left over from the painting of the Piccup Squared project that I finished this summer in time for our vacation.

    I had a few visitors today. One guy said that he did a lot of work with fiberglass boats and aluminum boats. Yesterday the gas meter reader was interested. The guy today was part of a crew paving our street.

Leftovers on the menu again; this time its green marine enamel paint.

 

    I cut out the second double paddle blank. The first blank has the blades glued and clamped in place. A sliver broke from one end of the second blank, so that is under the clamp, too.

    I glued but didn’t nail the blades to the blank. I may put on a coat of epoxy before varnishing the finished paddles.

    I have confidence in the glue alone after road-testing the first double paddle. When the paddle bounced on the highway at about 40 mph, the shaft broke at a know, but the blade glue lines held. Two cars ran over the paddle before I got to it to pick up the pieces.

    Time: 3 ½ hours.

    Costs: $10 for varnish and $5 for paint.

    05 September 03: I started with the double paddles. It’s been in the 60s F., so the glue had not completely kicked from the work that I did last night. At warmer temps, the Elmer’s glue should kick in about four hours, and the label says to wait overnight before sanding or painting.

    This morning, I glued and clamped the second paddle blank to the plywood blades. I was satisfied with the repair of the sliver that had parted form one end of the blank. In fact, I couldn’t locate the glue line.

    I’m interested in any differences between the two paddles, since the first one that I glued up has a pronounced reverse curve in the shaft and the other one has only a slight arc.

    After I put on a second coat of green paint on the hull, I’ll shape, sand, and epoxy-coat the paddles. Tomorrow I’ll varnish the paddles and install the eyebolts that accommodate the shock cord that secures the hatch covers. We’re planning an outing on Monday. Still on track to be done by then.

    Time: 1 hour.

A second coat of green paint does wonders.

 

    Painting: As was the case with the primer, the green paint barely stretched for a second coat – but it did, just.

    I’m pleased with the overall quality of the paint job and preparation.

    The fishes won’t complain, anyway.

    The hatch covers need a second coat of varnish. They soaked up the first coat.

    Time: 1 ½ hours.

    Costs: $5 for paint.

One double paddle is done and the other is being clamped.

 

 

    Paddles: I’m done with both double paddles. The first one that I made, with the reverse curve in the shaft, I rounded equally. The other paddle, which has a slightly arc only, I rounded on the face looking at the paddler and rounded less on the face looking away from the paddler. This improved the balance some.

    I compared these two paddles with the one that I built originally, the one that broke during road-testing. That paddle is much heavier, because I had shaped the shaft at 3/4 by 1 inch and rounded it to an oval profile.

    The new paddles have shaft dimensions of 3/4 by 3/4 and the blades are made of lauan instead of the much heavier and stronger bc pine plywood that I used on the road-tested paddle.

    I’ve decided to skip the epoxy coating and go directly to a couple of coats of varnish on the paddles. I notched each of the paddles at the center on the face looking at the paddler. This is a visual and tactile cue for persons new to boats. They often don’t know which paddle face goes where, even with the spooned blades ... .

    Time: 2 ½ hours.

    Later: I decided to make a third double paddle. I don’t like the balance of the paddle with the reverse curve. It takes too much muscle just to keep the blades perpendicular. I want to have some options, and the practice at paddle construction is good, too. I cut out the blank and blades and glued them together in about an hour.

    Tomorrow I’ll finish all three paddles. I did some more planing on the one paddle, thinking that it would reduce the weight at the ends, but the curve in the shaft is the problem and that can’t be fixed. Still, I’ll try it out in the boat sometime. Who knows ... .

     Time: 1 hour.

     06 September 03: I’m glad that I made a third double paddle blank. This one is beautifully balanced to the point that I’m being careful about how much wood that I remove while shaping and finishing. In varying degrees, the other two double paddles are not balanced; I feel that the pull and strain of maintaining the blades in the vertical position.

    This latest paddle blank is 3/4 by 3/4 to 7/8. The greater dimension faces the paddler. This must be helping the balance.

    I filed a center mark and I also filed a notch all around 12 inches out form the centerline on each side, for tactile index marks for hands placement. I’m going to leave the shaft squarish for now.

    I’m going to round up the Reverend’s double paddle, though; she expressed a preference for that after checking out the blank.

    Time: 2 ½ hours.

My fears about re-fairing the curve were unfounded. I can't tell any difference between the two boats.

 

    Finishing up: I put both of our Flats Rats side by side out on the sidewalk and took some pictures.

    I was interested in seeing if the profiles were different, in view of the extra fairing that I did on the second hull. I couldn’t detect any difference.

    I double-nutted the eyebolts that go one each side of the hatch covers. I had noticed that the nuts on the other Flats Rat were loose.

     There was a gotcha when I put long eyebolts instead of screweyes on the sides of the openings for the hatches. Because the hatch covers couldn’t shut because of the nuts being in the way, I had to cut notches in the locating cleats on the hatch covers to clear the nuts.

Black shock cord, 3/16ths of an inch, adds a nice touch to my little boat.

 

    I used the black 3/16-inch shock cord that I got the other day from Obersheimer’s to finish the hatch cover job. It looks great.

    I had a wood cleat – 3 inches – left over from the Piccup Squared project, so I attached it to the forward bulkhead on the centerline (and noticed a few days later that I had attached it to the aft bulkhead by mistake; it will need to be moved to the intended spot).

 

 

 

 

 

  

We must be in heaven, man! No powerboats allowed at Mendon Ponds Park near Rochester. The Reverend took this pic.

 

    08 September 03: We had almost perfect weather for the first launching of my little Flats Rat paddle boat.

    A high-pressure zone has been giving us day after ay of blue sky and fall-tinged warmth with 60s and 70s F. and a hint of tingle. It’s been T-shirt-and-shorts weather on the cool side.

     We went to Mendon Ponds Park south of Rochester near Pittsford and Locks 33 and 34 on the Erie Canal. Mendon Park is out in open country. There are three kettle ponds – glacial lakes – and we paddled on the largest of them, Hundred Acre Pond. There was a strong wind just short of white caps. That gave me a lot of information to ponder concerning the skeg vs. keel strips question that I posed for myself.

    We launched at a simple dock (no power boats allowed!!!) and were on our way in minutes.

    I carried a small, round ice cooler between my extended legs, and the Reverend had a six-pack-size cooler in her little boat.

    The lake is approximately ½ mile wide and 1 ½ miles long, by my estimate. Because it was formed by glacial action and the kettle-pond effect, its margins are regular and the overall shape is oval/circular.

Lily pads and beautiful white flowers graced our time on the water at Mendon Ponds Park.

 

    The depth is sufficient for paddle boats; aquatic grasses grow almost to the water’s surface all over the lake, and lily pads were present, too, but only in patches.

    A few white flowers persisted among the lily pads.

    We had the lake to ourselves except for a fellow old guy in a plastic mini-kayak of the sort that the Flats Rat gives some competition to.

    The old guy paddled across the lake then flipped onto his back and drifted with the wind.

    Our paths crossed once.

Goose gets goin' when we paddle too close by.

 

    As we paddled up the shore against the wind, we came near a gaggle of geese. After splitting into two groups moving in two directions, one group of four or five exploded into flight, honking, flapping, and generally complaining and accusing.


    As we made the turn and began to go downwind, I discovered that my boat with the keel strips had what at first seemed like a counter-intuitive habit of trying to round up into the wind if I paddled normally, dipping one blade, then the other, etc. etc., etc.

    At first I was puzzled, and I noticed that if I paddled on one side only I could maintain my heading, or would need to switch to paddling for a while on the other side only.

    I decided that the stern, which has a bit more volume than the bow, with my upright torso adding to the weathervane effect, and my weight establishing a pivot point aft of center, was accounting for the boat’s desire to round up.

    This is a desirable trait in a sailboat – weather helm – and I’m thinking that it’s a trait – a feature rather than a bug, in computer-speak – that I’ll hang with. The other option was to drag the paddle rather than paddle. This had the effect of controlling the boat’s drift downwind, too.

The Reverend's boat and mine both wiggle a bit as they are paddled; the difference between my keel strips and her skeg is mostly aesthetic; I like the looks of strips better. Keeps strips also fight oil-canning of the bottom.

 

     The Reverend’s little boat, which has a skeg instead of keel strips, did not act all that differently, except for slightly better tracking downwind. I’ll have to try her boat to see for myself. I noticed that both boats wiggle some when we were paddling normally, but it wasn’t any more pronounced in mine than in her’s.

      I like the keel strips and will continue to use them, because the lauan plywood that I used in both boats oilcans in her boat when you step in. I also noticed flexing when I tossed her boat onto the water while we were using it on our vacation a few weeks ago.

    This oil-canning is not a big problem, but the two single strips do give a lot of added structural improvement for the effort expended, and adds almost no weight. I copied the twin keel strip idea, which are aligned directly below the combing strips, from the Piccup Squared project that I recently finished. It’s a Jim Michalak design and a design element that he seems to use often.

The cockpit is such that I can comfortably rest my feet against the bulkhead while paddling. The Reverend will need some cleats to push against.

 

     One alteration in the Reverend’s little boat will be a few strips across the inside of the cockpit, forward, so she can have something to brace her feet against.

     When I built my little boat, I shortened the cockpit about an inch at each end after seeing that the best sitting position, leaning against the aft bulkhead, still made the boat trim a bit by the stern.

The Reverend could move her cut-down lawn chair seat four or five inches forward, but that would call for a more complex arrangement than just throwing in the chair and paddling away.

    Since I am taller, I find it comfortable to brace against the forward bulkhead and use a boat cushion to sit on, keeping out of the pint or two of bilge water I deposit in the boat when I get in (have to remember a big sponge to get rid of that water next time).

    I have noticed that sitting on one boat cushion feels right and sitting on two boat cushions feels like I’m in danger of bringing my weight too high for buoyancy.

    I’m planning on playing around with a simple built-in seat. I have several styles to pick among in my library of boatbuilding books.

    After drifting down the lake, we had lunch at the picnic area across from the dock; it’s called Pond View. We retraced our route around the lake, back to the dock.

    We had one of the most pleasurable times on the water that we’ve ever had together. I still have a smile on my face as I write this down the next morning.

Trim looks just about right.

 

    On the way home, we stopped at a bookstore or two. I got a copy of New Plywood Boats by Thomas Firth Jones. I have read and enjoyed another of his books, Boats to Go. I read some of the newer book this morning, about a kayak design of his. He mentions the downwind experience of paddling on one side only, the use of foot-braces, and his preference for stringer construction over stitch-and-glue.

    In fact, it was a reprint of an article of his, which appears in this book, that helped me articulate my own aversion to stitch-and-glue and got me thinking about ways to used stringers and frames.

    The reprint was on the Internet on the Boatbuilding magazine website, I believe. I've made a few attempts to find the article but so have not been successful.

    Jones uses half-round pieces of moulding spaced 12 inches apart, across the bottom of the kayak design in New Plywood Boats, to increase the strength. He believes that these simple sticks make the 1/4-inch plywood more like ½-inch plywood in strength. This is a trick to remember, and it could be used with or without keel strips. They would at a minimum add a pleasing design element. Square strips at the feet would provide foot-braces for paddling, and strips aft would give either a platform for a seat of plywood or cane, or whatever, or would simply keep a boat cushion out of the bilge water, which in the little boats I build collects right under the tailbone, since where you are is going to be to low point of the cockpit.

    Here’s what Jones sez about wind:

“It seems that there is no perfect kayak shape for every condition of wind and water, and for that reason my younger son in Italy owns half a dozen kayaks. A bottom with no rocker – and most designs form the legendary builder J. Henry Rushton have virtually none – produces the straightest running boat in light wind or with strong wind forward. With a strong wind aft the rockerless hull with its deep forefoot tends to slew around broadside, sometimes more than can be corrected by addling exclusively on one side, and the only way to control the boat is to drag a paddle blade."

    Jones also talks about the length needed to provide momentum between strokes. He believes that 12 feet “may be nearly the minimum length that a paddling boat should be if the owner expects to enjoy using it.”

    I’m fired up about single-sheet-length boats – 8 feet or less – that I can build in my basement and carry up the stairs when finished. Basement boats. One restriction is that stubby boats demand extreme rocker. Otherwise the ends are not clear of the water, which is generally not good. A pramlike boat with a flat bow would plow water like a tug if the bow were not elevated enough to stay clear. The ability to keep the nose in the air comes from rocker. Rocker makes for a lively little boat; skegs make it so there is better tracking.

    The length limits the speed at the top end, but the difference isn’t more than a mile or two her hour. And when you’re on the water, you’re already happy, so who cares about a mile or two an hour difference in speed?

I watched carefully while the Reverend paddled her boat, to see if there was any difference in her boat and mine. There wasn't.

 

    I carefully watched as the Reverend paddled her little boat. The boat doesn’t dig in at the stern, probably because of the wetted area – pram ends greatly increase wetted area, which erases the canoe/kayak stern phenomenon of digging down when the paddler takes a stroke.

    I also noted that her little boat had noticeable glide ability between strokes, upwind against a stiff wind, no less, and that on 8 feet of length.

    Jones would look to the amount of effort that it takes to use our boat vs. the effort it takes to use his. I’ll be checking on that when I build a strip canoe such as the Wee Lassie, which is around the 12 feet in length that Jones likes.

    The kayak design that Jones discusses in his book offers 225 pounds of displacement in 13 feet of length. Our stubby boats yield 300 pounds of displacement from eight feet of length. It's all about tradeoffs and compromises.

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