The hull is characterized by a low wave
piercing bow which is only now being adopted by the most high tech
racing multihulls. The other defining feature is the high raised
stern. These two features work together well to make it both
seaworthy and fast.
The high raised stern has been adopted by
the many modern replicas of Polynesian voyaging canoes and besides
the obvious advantage in a large following sea, it counterbalances
the bow and prevents it from diving too deeply under the water. I've
found this to be true also with my 6M [20'] hull described in this
Light weight modern beach catamarans and
early modern multihulls can sometimes be difficult to tack through
the eye of the wind without stalling. The most delightful surprise
from this va'a motu is that the problem has totally disappeared. It
tacks as quick as a little dinghy, with or without the optional jib,
and even in steep head seas.
However, all boat design is a bundle of
compromises. That high sweeping stern does not contribute to the
load carrying capacity when sailing in smooth conditions or at rest.
The rocker of the bottom panel in the
stern may prevent you from reaching the highest multihull speeds but
12 knots is still easy to attain in the right conditions.
The ama also has a low wave piercing shape
with a vee deck to shed water and enable it to quickly climb out of a
wave. Flat ama decks are fine on larger multihulls where the ama
buoyancy can be two to three times the displacement of the entire
craft, but with a smaller single or double outrigger where the
buoyancy is much less, you want an ama that climbs out of the water
as easily as it passes into a wave face.
This ama also has sufficient rocker under
its stern to enhance its tacking ability.
You will see banana shaped amas especially
in Hawaii where the ability to land in high surf is most important. For
most of the sailing that is done in this size of canoe, a
straighter wave piercing ama is faster and will throw less spray back
at you at speed.
The ama in this manual is built like a
foam and fiberglass surfboard with a central web of thin plywood. It
is ultimately the safest solution because no matter what the extent
of damage, there will still be some buoyancy there to keep your canoe
The ancient va'a motu used a large counter
balancing beam on the non-ama side to allow crew members to use their
weight to prevent the solid log ama from submerging. With modern
light and buoyant foam amas it is no longer necessary , but there are
hiking seats on both sides and their use does improve performance.
The ancient rig used by the Tahitian va'a
motu was a very high aspect ratio vertical sail that with modern
materials would still be competitive today. It had a interesting
hook at the top that I know was being investigated by a university
wind tunnel but I don't know the results. The main disadvantage of
the ancient one's rig was that it was like a gigantic windsurf rig. It
had to be fully rigged and tipped up or down with no reefing or
furling. The performance was good but the practicality was low by
The design in this manual uses a modern
high aspect fully battened sail but has an unusual sheeting
arrangement. Narrow high aspect sails with a fat head would twist
too much without a powerful vang under the boom to pull it down. Both
the Chinese with their junks and the Tahitians found a lower
stress way to do it. Multiple sheetlets are attached up the
leech of the sail at several points to control the twist at the top.
This doesn't really work very well if the leech of the sail is almost
above the stern of the hull, but in the case of a junk or a va'a
motu, the extra length and height of the stern provides a perfect
location to anchor the sheet without too much down pull on the leech
of the sail. The tension on the sheet (and the pain in your hand)
are reduced with this system. A ratchet block on the deck also helps.
Reefing is as easy as with a junk rig,
just lower the halyard. You can re-hook the downhaul but it's not
Most Tahitian outriggers still use a
crossbeam system where the forward beam is quite stiff and
substantial but the aft beam is flexible. This allows for some
independent movement of the ama in response to the waves, and has
been adopted in different ways in other island designs such as the
The design in this manual uses a smaller
section crossbeam aft and you can readily see the effect when
The Safety Ama
The safety ama is a modern day Hawaiian
innovation as the result of racing their sailing canoes through very
rough conditions between the islands. It will not completely prevent
a capsize but will slow it down to the point where it can usually be
It is also easily removable in the event
of a 180 degree capsize so that the canoe can be more easily righted.
How long? How much?
favorite questions. I've been doing this for a long time and I have
every tool you could want so that when I build a new prototype, there
is little wasted time or motion. This one took about 220 hours to
get sailing, including cutting down a bigger sail to make mine. I
bought the mast second hand and I would recommend this too as there
are many unused centerboard boats and beach catamarans sitting in
backyards. Buy the whole thing and you'll have a box full of blocks,
cleats, rudders and many more miscellaneous parts that you can use.
Don't ask me how much it costs to build
because it's almost meaningless considering the many countries where
builders live. Just study the materials list and price it out for