A modular approach to
SOT kayak sailing and paddling
Sit-On-Top (SOT) kayaks are easy boats on which to
learn to paddle. They have none of the “get
inside the coffin and drown” psychological identity
that one finds in the Sit-Inside boats and they’re
amazingly adaptable to a wide range of paddling activities.
It also doesn’t hurt that they are pretty straightforward
boats to rotomold, which makes them very cheap to
produce in large numbers.
I didn’t envision just one boat for this niche
in the home-built kayak market. Instead, it came to
me that there would need to be at least three models
that could address the wide-ranging styles of boating
interests in this area of the kayak world. The result
was a couple of very clean, SOT models at 14’
and 16’ called the Corona and the Back Bay.
The third model was going to be called the Wahoo,
as it was specifically designed for the folks who
spend a lot of time fishing with their SOT’s.
I’ll get to the Wahoo in the next article for
kayaks have none of the “get inside the
coffin and drown” psychological identity
that one finds in the Sit-Inside boats.
As a canoe and kayak sailor and a guy who had just
been out for a test drive on the Hobie Island, which
is based on their 16’ SOT Adventure model, I
wanted to offer my own take on what makes for a truly
fun and stylish, sailing SOT kayak. The result was
that a fully integrated system of component parts
was designed for the basic Back Bay. This modular
approach allows the Back Bay to go sailing by simply
adding a system of light weight, easily built elements
that quickly convert the SOT to a single aka sailing
boat called the Scorpion, OR a double aka sailing
boat, called the Doubloon.
The Corona and the Back Bay are virtually identical
models, save for their respective lengths. For the
purposes of this article, I’ll focus on the
Back Bay version and all the potential add-on systems
I’ve incorporated in the design.
The Back Bay SOT kayak
|The Back Bay can
be configured with a large, open tank well set
aft of the cockpit, or built with a watertight
hatch cover for internal storage in a conventional
Beam overall main hull
Depth of hull max
|48 lbs. or less
This boat is built in the S&G style of construction
in 4mm marine ply with 6 oz. plain weave fiberglass
set in epoxy on the inside and outside of the hull
for full laminate sandwich strength. The build process
uses external cradles as strongback supports, ensuring
that the hull goes together with minimum hassle when
handling the rather slender and longish hull panels.
The boat is bulkheaded internally at three key points.
These bulkheads create not only integrated strength
in the design, but they also cleanly separate the
hull cavity into four unique volumes for gear storage
and watertight flotation.
The Back Bay can be configured with a large, open
tank well set aft of the cockpit, or built with a
watertight hatch cover for internal storage in a conventional
Scorpion Sailing SOT
This is a Sit-On-Top
design for fun sailing, paddling, or Mirage
peddling, as the builder desires.
|56 sq. ft.
Draft (board down)
This is a Sit-On-Top design for fun sailing, paddling,
or Mirage peddling, as the builder desires. The sailing
daggerboard drops through an insert in the Mirage
trunk. (if the peddle function is chosen during construction)
The owner can omit the Mirage capability if so desired
and a simple slot for the daggerboard will substitute.
Having the aka gull wing form set well forward permits
a full paddle swing arc. This setup will allow the
owner to power sail in light air with both the paddle
and the sail providing thrust. It is also possible
to offset the daggerboard trunk and utilize the Mirage
drive for a power sailing option.
The amas are positioned to optimize capsize resistance
when sailing off the wind and have sufficient buoyancy
to resist capsize with full sail up in a 20 knot breeze.
The amas do not touch the surface of the water at
rest and provide only minimal wetted surface drag
when underway by paddle or peddle.
The aft deck can be configured as a watertight hatch
with full access to the aft sections of the hull,
OR a large, diving tank well with self-draining ports.
The cockpit is fitted with self-drain ports under
the seat as well as forward, in addition to the daggerboard
slot. There is a watertight deck plate just forward
of the seat, between the knees of the sailor/paddler
to provide secure storage for critical items that
may be needed on a routine basis. The foredeck has
a watertight hatch cover for bow storage needs.
|The amas are positioned
to optimize capsize resistance when sailing off
the wind and have sufficient buoyancy to resist
capsize with full sail up in a 20 knot breeze.
The rig is a fully battened Dacron sail with two
reef points and a multi-section, self-supporting mast
which steps into a sealed mast socket in the hull.
The mast and boom sections can be aluminum or carbon,
as budget permits. The sail choice is open for the
customer as long as it can be balanced with the fixed
positions for the mast and dagger board. The Cunningham
is run to the deck of the gull wing aka to keep the
rig on the boat in the event of a capsize.
With 56-sq. ft. of sail on a 90-pound boat, this
will be a decently speedy boat without being in over
its head all the time in a stiff breeze. I suggest
two reef points in the sail to allow for sailing in
a wide variety of conditions.
This will be a wet boat at speed, yet there are no
worries at all for flooding and sinking save for a
truly nasty trip over a reef that shreds the entire
underside of the craft. The bow, cockpit and aft hull
volumes are all independent, sealed compartments,
as are the ama volumes.
Reentry from a swimming session will be easy with
a simple, sling ladder much like those used by rock
climbers, called etriers.
ft. of sail on a 90-pound boat, this will be
a decently speedy boat without being in over
its head all the time in a stiff breeze.
Sliding foot pedals in the cockpit control the rudder.
The rudder flips-up when it encounters an underwater
obstacle, returning to the deployed position once
past the obstruction.
The boat is constructed in a multichine, marine plywood
style with epoxy glass laminates inside and out in
a stitch and glue style. Stainless T-Nuts are embedded
in the hull deck surface from below to provide a secure
set of mounting points for the aka wing. The amas
are held in place on the aka tips by large bungees
and a notched lock system. This system provides for
quick setups on the beach.
You just fit the aka to the foredeck, insert four,
1/4" threaded stainless screws with comfortable,
knobbed grips and screw down the aka wing. The amas
slip onto the ends of the aka and you lift the pair
of 3/8" bungees up and over two raised hooks
on the aka ends to secure the ama in place.
Doubloon Sailing SOT
|The Doubloon is
essentially a solo craft and it carries the same,
56 sq. ft. sail, but the overall potential of
the boat is expanded through the use of dual akas
and full side trampolines.
The Doubloon is the second variation on the central
SOT theme of this group of boats. In this design,
I am looking to provide a more expansive utility application
for the base, Back Bay SOT version. The Doubloon is
essentially a solo craft and it carries the same,
56 sq. ft. sail, but the overall potential of the
boat is expanded through the use of dual akas and
full side trampolines.
The akas on the Doubloon are spaced to allow for
a full paddle stroke with the boat setup as a trimaran.
There are two sections of tubing that span the opening
fore and aft between the akas from which the tramp
is mounted. The trampolines are designed to roll-up
on the outer tube section, much like a window shade
and they are deployed by an endless loop of light
halyard line. With the tramps fully deployed, the
inner tube section lifts up and over a holding pin
in the aka and the sailor applies as much tension
to the tramp as he feels he needs by hauling-in the
endless loop line and cleating it off. If a paddling
session is desired, he simply pops the jam cleat and
pulls the line to roll-up the tramp on the outer tube
section. This procedure applies for both port and
Like the Scorpion, the Doubloon can be built to utilize
a Mirage drive in the center well and the need to
roll-up the tramps for paddling is essentially negated,
(though it is nice to have the option once in awhile
as Mirage drives are hard to maneuver in tight places)
The aka beams are held to the deck of the Back Bay
hull with the same, threaded knob strategy for quick
setup and takedown times. Similarly, the amas are
held to the aka ends with hefty bungee cords for the
simplicity of use. There’s another, rather invisible,
benefit to using the bungee cords for ama mounting.
Because they are being held in place through a fairly
dynamic hold-down system, the amas can move about,
ever so slightly, while underway. This allows the
amas to have some structural “give” and
the result is that the banging and thrashing that
is typically experienced by the ama, is somewhat dissipated
through the flex of the joining system.
The Doubloon configuration allows the sailor/paddler/peddler
to bring along extra gear, which can be lashed to
the tramps in waterproof bags. They can also take
along kids, or perhaps someone special, who could
lounge out on the tramp surface while lazily sailing
along for a sunset cruise on a warm summer evening.
All in all, I think the Back Bay SOT should be a
really fun boat to own for warm water/warm weather
boating adventures. It has the capacity to carry enough
gear for several days out on the water. When rigged
with a sailing system of your choice, it can also
cover some pretty good distances if the winds are
favorable. Plans for this boat and all its variations
will be available from Duckworks.
Articles by Chris Ostlind: