| What is foremost in my mind is that I have seen
novices reduced to tears by the difficulty and danger
of trying to control a powerful high aspect rig. Having
spent the time and effort to build a family cruising
yacht, the family doesn't want an air of fear and
frustration. Hence my attitude was to design yachts
which go very efficiently under easily serviced 4-stroke
outboard power, and get builders mobile as an affordable
motor cat adding sail to taste. We are not talking
about a conventional fishing power cat, trailerable,
25 x 8 feet with high deep hulls. and twin 200 HPs
on the back giving 45 knots and scoffing juice like
Billy Bunter..
28' Gumboots Motorsailer with
Lateen Rig
click image for larger view
In the Gumboot
28 case we are talking about longer lower
and wider. Sail cats motor well, and tris even better
if you can afford a sail drive with feathering or
folding prop. We have
- standing & elbow room galley (2 burner, sink
and big chopping board at cooks height),
- A self composting head in a sealed ventilated
aft room with a shower big enough to dress in, &
a sink,
- an office big enough to work in,
- a double bed and twin capsize bunks,
- a warm lounge-viewing-navigation pilothouse where
4 people can eat or play cards,
- a sheltered 8 x 6 cockpit, and 4 stowage holds.
Having built all this (or the smaller
Alleycat) you can spend 20k on sails and come home
from your first sail shattered, disillusioned, and
angry with the designer. Or you can say - "hell
I'm about stuffed I'm going to forget the daggers,
rudders and rig for now and motor for a season".
You'll be on a mooring and surrounded by other far
more expensive boats. Off to Ebay for a 4 stroke motor
from 15 to 60HP, or the dealer and drop it in to the
cockpit nacelle, hook up the wheel in or outside or
both. Or use the tiller thru the door where the nacelle
joins the cabin.
You can now overcome windage and tide, clear your
mooring and motor for 50 nautical miles on a jerrycan.
You can learn the local waterway, where the winds
blow, when & how hard, how the bar works.You will
have a great time and any reluctant members of the
family will be converted or seasick, at least you'll
know. You can get to know & charge your electronics
and how your boat handles, practice "person overboard"
drill and check how much lee drift she has. You can
check how she takes steep waves and balance her.
You can cruise about economically, and accumulate
a tender with a motor big enough to act as an emergency
main. A modern 6Hp is ideal, weigh 25kg and use 1/2
gal per hour pushing Gumboots at 6 knots. You can
set up a bracket for it on the rear beam, and stow
it in a hold. (Alleycat is its own tender but you
could use a spare light motor, even an electric with
a bracket so you can run it thru the dunny hole in
a storm.)
In these boats you can cruise at 10 miles in an hour
on an American gallon. and depending on the engine
a top speed of 12 to 20.
You'll have a great time and be real glad you built
the boat.
As you cruise people will want to look her over. You
say sure but I'd like to look at your rig. Do so At
the yacht club you'll find racing keelboat types who
change rigs like we change clothes. They will possess
discarded rigs with masts "too heavy" and
sails ditto. Some hardly used. The owners wont want
much, the gear will be stuck in shed roofs and out
in the yard. Inspect it closely, measure it up and
post the dimensions on the JGBuilder's
group with Urgent in caps. I'll see if
it works., calculate speeds for force 2, 3, 4 , 5
and 60 percent of capsize windpeed. Replace all wire
if you use it.
As Gumboots/Alley barely need boards and the dagger
design will be flexible, you can set a second hand
jib and main on the huge mast step area provided,
raising it on a halyard box if it wont clear the pilothouse.
If you buy it off a local they should be curious enough
to come out and help you tune it
Or you can build wooden, or adapt a couple of alloy
20 (Alley) or 25 ft ('boots) masts to set up the twin
raked splayed "lateen jib" rig. You can
sew sails or flip over second hand genoas.
I also should point out that if a conventional rig
borrows from aircraft theory (half a plane on its
side) then this is the equivalent of a delta wing.
Its notion is to obtain the necessary lift area while
decreasing the wingspan (mast height). This makes
the plane more aerodynamic, or in the boat's case
makes it easier to motor upwind. Without a slot effect
(low aspect blade jib directing high speed spillage
around the outside of the main to create low pressure)
this rig isn't going to point high but that's the
thing - you'd only choose it for a motorsailer. Gumboots
(like most cats) presents so little frontal area at
such narrow angles that it can be driven directly
upwind efficiently under power, instead of clawing
your way upwind at 40deg tacks, with the bows being
blown off course every time you come over a wave.
You'll go a hell of a lot fatter in Vmg going straight
upwind using a gallon an hour than you would with
the best of rigs. Even if your course isn't directly
upwind I'd consider motoring straight upwind for an
hour, so that the rest of the days sail might become
a fast beam reach. It's very like cross country skiing
to a higher point - you take your downhill skis and
catch the lift to a higher point than your destination,
then enjoy a days downhill skiing instead of a days
slog.
You'll also notice this rig has a separate forestay
so you can drop the furled sail to the deck, coil
it up and put it in the fore-hold, still attached
forrd if you wish. It would also be possible to rig
a small battened beach cat main on each mast if you
cant live without them.
The rig is not dissimilar to what Volvo Ocean Racers
(VOR) do when they break a mast - they rig a lateen
(usually no 2 jib ) off the boom or mast stump. It
gets them home, often at 7 knots, but its far under
standard sail area. It is used because its easy to
rig and control, and it does the job. The longest
sail edge is controlled and you can de-power, drop
the sheet without hurting the rig Most ocean Multihull
capsizes occur because sailors can't get to the rope
cleat quickly enough to let go the sheet - they can't
de-power the rig before the gust puts the rope clutch
out of reach as hanging on becomes a priority. . .
I think it would be possible to use light battens
parallel to the forestay (luff).. I also think the
TLJ would work best if the foot and leach were equal
length so that the stay is close to 45 degrees and
the sheeting angle is constant no matter how much
you roll up the windward jib. Because of the incredible
wind pressure the rig can take without lifting a hull
sails should be cruising dacron or even canvas. Other
possibilities are stowing a jib and hoisting the other
on its "wrong" mast, thus angling the rig
up to 40 degrees across the boat.
A sophisticated version would see the tack on a
forebeam traveler and the head on running tackle between
mastheads. The fore and backstay could go thru a masthead
block so that each rig could be tensioned by tightening
the backstays, and bending the masts slightly. Note
this also tensions the mastheads which are slightly
inboard of the hull C/Ls/. The mast steps are
4 feet from the cat CL and the heads are at 7 feet.
It would be incredibly efficient to hang the foot
of the lee genoa right outside the hull so that the
clew is lashed to the boarding step. Every last puff
coming across the boat (usually at 45 degrees). One
of the biggest losses of power (and sources of annoyance)
is the high speed wind funneling thru the space where
the humans are, between the sails (usually the boom)
and the sea or cockpit.
Jeff Gilbert 2007.
Other Articles by Jeff Gilbert:
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