PIRAGUA18, SWAMPBOAT, 18' X 3', 90 POUNDS EMPTY
Rhett Davis brought this
prototype Piragua18 to our Midwest Messabout, hauling
it strapped to the roof of his compact pickup while towing
This is the basic 14' Piragua
stretched another 4' to gain a good amount of extra capacity.
The shorter boat is a bit loaded by two adults but this
longer one can handle them.
I had a chance to try the Piragua18
for a brief time at the messabout. It was about what you
might expect. I paddled it solo so it was far from fully
loaded. It feels "longer" than the shorter boat
of course, tracks straighter but is harder to turn. It
might be possible to reduce the depth of the bottom skid
to get faster turning but then again a lot of people want
the straight tracking. I'll bet it is faster in calm conditions
but maybe slower on windy days where the windage of the
extra 4' becomes a bother. I was able to stand up in it
but wouldn't do that regularly - it is too tippy as would
be any boat this narrow and light. Want to make it more
stable by going wider and heavier? Go ahead but then it
will be too wide to use a double paddle with any comfort
Piragua18 will float 500 pounds before
its bow and stern start to drag the water. The empty hull
should weigh about 100 pounds leaving 400 pounds for people
and gear and that should be enough for two grown men.
I've also shown on the drawing how I
would rig a boat like this with an electric trolling motor.
A typical trolling motor and 100 amp hour trolling motor
battery will together weigh around 100 pounds and this
hull will handle the weight of the rig better than the
shorter boat. I'm thinking that is no need to get a large
motor. The smallest I've seen for sale lately was 30 pounds
thrust which is usually rated at 1/2 hp. That should drive
the boat about 5 mph. Better would be to throttle to about
half power which should give about 4 mph. The battery
has to be a full sized deep cycle trolling battery. The
batteries should never be deeply discharged, in spite
of their name, and for long life they should not be discharged
more than 70% of their capacity, and they should be promptly
and fully recharged after use. At full power the 100 amp
hour battery should give about 1.25 hours of endurance
for a range of about 6 miles in calm conditions. At half
power the battery should give about 3.5 hours endurance
for a range of about 14 miles. Note that at high rates
of discharge a battery has inefficiencies that prevent
it from delivering its full charge. Anyway, power and
hull should together weigh about 200 pounds, still leaving
300 pounds for folks.
This hull might be a good starting point
for a beginner's sliding seat rowing boat. It has the
length and light weight and wide open interior that would
take rails for the seat. She's way too narrow for rowlocks
mounted on the wales. You would have to add riggers. No
doubt the best approach would be a drop in unit that has
rails and riggers and foot braces all bolted together.
You would have to secure it to the hull somehow but that
could be done in such a way that the unit could be removed
and the boat returned to its canoe configuration.
Anyway this is powered I think it would
be a good camper's boat assuming there is no real rough
water about. The ends are boxed in with buoyancy/storage
volumes and the center 9' wide open for sleeping. The
hatches into the storage boxes are small, only 6"
wide, in order to make them less likely to take water
in an upset.
Construction is simple nail and glue
like the original Piragua.
Three sheets of 1/4" plywood will do it. I don't
think these boats need epoxy coatings if they are stored
under cover. The chine corners need to be armored with
fiberglass set in epoxy and the inner seams given a fillet
of epoxy putty to keep water from creeping into the seams.