This is a story of building a
boat in 2.5 hours. I was twisting my sister's arm, trying to get
her to build a PDRacer.com.
She was interested, but wanted to build a small kayak first, something
like my flats rat, which is a flat bottomed version of Gavin Atkin's
Mouse, only it can carry a lot more weight. We were talking about
a few building techniques like chine log construction and stitch
& glue, but they all seemed to take too much time. Then I
rememberd that back in the 1950's, there were a lot of boat plans
in Popular Mechanics. A number of them were very simple little
boats that used "plank construction" technique,
where a 1x12 or similar plank of wood is used for the sides and
sometimes the bottom. A couple of examples are the Paddle
Pusher and the Wheeled
). This is a VERY FAST method of construction, it is as simple
as chine log construction, but you don't have to make all the
chine logs -- all you do is cut the sides
and glue/nail on a bottom. The day after we talked about
this type of building, she went to the hardware store and started
building a regular flats rat, with plank sides.
I started kicking around the idea of a very small kayak for me,
something that was small enough to carry inside my minivan, yet
was big enough to carry both me and one daughter. Would use it
as a tender for my larger sailboat, and also as a boat to use
in the small fishing ponds. A little drawing time later and I
discovered that with 2 of the 8' planks, I could make a kayak
that was 5'5" long, 32" beam, and a 350 lb load would
have 4.5" freeboard left. Wow, that is a lot of load carrying
for such a small boat! So the project went on "the list",
and it looked like I wasn't going to build it anytime soon.
Then all of a sudden I got the opportunity to help a friend raise
a sunken boat. One catch though, the boat was near the shore,
but possibly far enough off that the suction hose of a gas engine
pump wouldn't reach, and we would need a small dinghy to carry
the pump near the boat, possibly pumping as we towed it to the
ramp compensating for a possible hole in the bottom. I didn't
have any other boats at the time that would be suitable, so what
a perfect opportunity to build this little kayak!
Not much to this boat, just get yourself 2 of the 1"
x 12" x 8' planks. Cut 30.5" off the ends of each,
you will use these for bulkheads. The remaining portion is
to make your sides.
(click thumbnails to enlarge)
With these dimensions, you will end up with a boat that
when loaded with 350 lbs, it will have a 6.5" waterline,
leaving you 4.5" of freeboard left. If you want a boat
that will carry more weight, consider making the sides longer.
32" is a really good dimension for the beam, if you
want to paddle it, I would suggest keeping it that same
make the curve in the end of the sides, start by drawing a
straight line that starts from 2.5" down, and goes to
11" back on the bottom. Next you will draw a series of
tick marks, starting from 7" back and 3-1/4" from
the bottom, and continue till you get to the last mark at
17" back. Each of the tick marks are 1" apart. Connect
the dots, cut the curve, and that is the tightest bend that
I could make 1/4" BC pine plywood bend around.
|Here I have cut the ends off the planks and saved them for
bulkheads later. Also I cut the curves in the ends of the
Glue and screw the transoms
on, they really are just 2.5" pieces. I didn't even
cut a bevel in them, just 2.5" x 3/4" strip of
bottom is 6' long, from end to end around the curves by
32" wide. I didn't have a piece of 1/4" plywood
that big in stock, so I used a couple of smaller pieces,
here is the bigger one. Lots of titebond II glue on the
sides, if the glue isn't squeezing out of the joint and
dripping down the sides, then you aren't using enough glue.
I figure that 50% loss of glue to dripping and mopping up
with paper towels is perfectly acceptable, especially at
how cheap titebond II is. The nails I use are 3/4"
bronze ring shank nails, they hold like a screw, but are
fast to install like a nail, and if you need to cut thru
the board later they won't mess up your saw blade.
I nailed the flat part on first, then leaned on the plywood
and nailed along the way to get the plywood to hold it's
curve. I am often asked by new builders how I was able to
bend the plywood. Well, if you try to bend it in the air,
it is difficult. But if you are bending the plywood around
a form (like the sides of this boat), it will adhere to
the form. The most important thing to do is bend it a little,
and put in a nail, then bend some more, put in another nail.
This boat uses a very simple curve that is very easy to
get the 1/4" plywood to match.
|The middle was flexing up a bit, so I put in
a couple of screws to hold it down. Later I'll remove these
I put the other half of the
bottom on, and it is really looking like a boat.
|To join the bottom pieces, I put a butt strap
across the inside which is really just a strip of plywood
that is glued on. The water bottles are to put some pressure
on the joint when it is curing.
To save time, I didn't cut
a bevel into the transoms, I just used rectangular boards.
I sorta missed on this one, and created an even bigger gap.
No problem, I am going to just tape up the seam, and put
an epoxy fillet in there.
thing I need is a stick with a round end, sort of like a large
tongue depresser. I chuck a 5" sanding disk into my drill
press and use it like a bench disk grinder. Now that I think
of it, I probably spend more time using my drill as a sander,
than for drilling. I sand all sorts of stuff like this, really
is handy to use.
I need to figure which filler I am going to use. I only had
a little bit of talc left, and I have a couple of repairs
on my fiberglass boat to do, so I didn't want to use that
up. So I took some sawdust and ran it thru my blender. I mixed
this 50/50 with wheat flour to make it less rough. I have
previously used 100% wheat flour for fillets, and while it
is VERY smooth, it is also a bit on the lumpy side and takes
a lot of flour. The sawdust will help bulk up the filler quicker.
Next time I think I'll use 70% flour, because the 50/50 mix
was a little rough.
|Give it a good shake, and that is some good
looking filler. Notice how there is less of the mixed filler,
than of the original unmixed portions. What is happening is
that the flour is filling in the space between the sawdust,
so when mixed it is a smaller volume.
Mix enough into the epoxy
that it makes a peanut butter like substance. I mixed in
a little too much filler, but it will still work OK.
|Smear some into the joints, and preso they are
I didn't do the inside of the chines at this time, I was
in a hurry to get the boat done and on the water. Later
I'll come back and fillet those too.
To stiffen up the ends, I
screwed on a couple of scrap pieces of plywood as decks.
Later I'll add in the bulkheads and fully deck over the
bow and stern so they are floatation chambers.
Now for the skid. The skid is an important
structural member, it prevents the bottom from "oil
canning" - that is when the bottom flexes around. My
first skid was 1/2", but when I tried to bend it around
the bottom, it snapped right off.
The next skid I made was
only 1/4" thick, and it was able to take the curve
just fine. Lots of glue and screwed right thru the skid
into the bottom. Later I pulled out the screws and filled
up the holes with thickened titebond II glue.
quick coat of latex exterior house paint on the outside and
bottom of hull, a total of 2.5 hours of labor
and I take my first spin on the water !!!
Wasn't sure if I was going to like it, so it was nice to
stop and take it for a test paddle. Not only do I like it,
I love it. I can really see how this is going to be a fun
boat to use.
Lots of other details to finish up, starting with airboxes
to make it self rescuable....