Power/Sail Sail/Power Cruising discussion. Simple Jib-Stay Sail-Lateen rigs
- So whatcha think?
The neat thing I am writing about is that Jeff Gilbert has, in the
Yahoo group jgbuilders photo section, sketches of a couple of his
cats, Gravel Truck and Gumboots, using what he calls a lateen rig. He
sets the mast (masts) rearward and rigs a jib to it. The sail is
loose footed (no boom) and is intended for downwind runs only. He
suggests setting 2 of them, side by side, on his catamarans. Makes
sense based on his note below.
The following is from JGBUILDERS group, which is for those interested
in Jeff Gilbert's catamaran designs. He supports the concept of low
cost cruising w' motorsailers that are more motor than sail oriented.
1. Mercenary thoughts on Sail versus power- the gravel truck etc.
Posted by: "jeff gilbert" jgilbert@... jgilbert49
Date: Thu Jan 31, 2008 3:18 am ((PST))
Much to tell about the decisions that saw me wish to design a powercat
which can sail, as opposed to a sailcat which can motor.
The point is that many people own the latter, but use it as the former.
When they add up their season's "sailing":, they find that an
astonishing proportion of their on-water time is spent positioning
themselves under power.
The crew of "Sunstome" (40ft Spark Stevens Mono), tying the knot in an
80,000 mile10 year circumnavigation, said in "Yachting World" that
their most important piece of on-board equipment was their long-range
Food for thought.
Fuel may reach as much as 2 bucks a litre soon.
The whole point about powering is that the fuel you use in your
20-something-foot cruiser isnt creating the crisis. The crisis is
caused by the showoffs who can't get on the water without a 1000 HP
planing beast which consumes a average families yearly car supply in a
day trip. They can afford it, but the planet cant.
If you have a 20 -odd boat that needs 12hp to get along nicely at 6
knots (say Gartsides "Wayfarer", or a Redwing) you have a choice, and
you should use it.
You can pay $10,000 for a lovely Yanmar and drive train and do it on
just 3 litres an hour of Diesel
You can pay $ 3000 for a nice 18HP Tohatsu 4-stroke OB and use 4
lites an hour of gas.
You can pay 500 bucks for an old 2-stroke OB and use 6 litres an hour.
Which one, or which combo pays depends purely on how much you will use
the boat, whether the diesel smell will piss you off, and reliability
considerations. Remember an auxliliary OB isnt so much use if it uses
different fuel from your main.
One power option Gilbert leaves out is an air cooled lawn & garden /
commercial engine, IE Briggs & Stratton or similar power. Yes, such
gas inboards are a difficult to manage, because of fuel fumes, heated
cooling air, and noise. But that's not my main point.
Gilbert shares a philosophy similar to one stated many years ago by
Bolger/PB&F. Also Jim Michalak in a recent newsletter, espouses a
similar view that simple and less is better. I'm sure both Michalak
and Gilbert are influenced by the senior Bolger.
I have a copy of Bolger's "Folding Schooner" which has a chapter about
a 25' motor sailer with outboard power. Bolger designed it for a
contest. It won. In the essay, he says pretty much the same thing
Gilbert says above about sailing a powerboat, rather than powering
sailboats. Bolger followed this design with the 26' sailing Diablo
that Bill McKibben built and named Ada. In BWAOM Fast Motor Sailer
chapter, this boat is called the first Fast Motor Sailer. The 2nd and
current FMS is an interesting boat with a full dipping lug rig. It is
intended to sail OR motor, and Bolger is very proud of this boat's
ability to do both pretty well.
Bolger's SMS, small motor sailer with an inboard diesel and a dipping
lug is also an interesting boat. It is not a completed design but a
concept published in MAIB? In the essay, Bolger states he intends the
diesel to be running all the time, with the sail rig assisting. The
combination would yield high performance (always as fast as a World
Cup racer?) and efficiency. SMS is a 22' boat. The implications of
its design board efficiency translated to a Loose Moose size sharpie
The 100' Sir Joseph Banks in BWAOM is also a motor sailer which uses
power 100% of the time with a sail assist. Again the intent is
performance and efficiency. JB is intended to keep a delivery
schedule at minimal operating cost.
IMO, a Martha Jane, or the Delaware cruiser (Jochems Schooner hull) or
most any Bolger sharpie could be rigged with the JG proposed Jib only
rig. The lee boards could be eliminated or at least reduced in size.
In an MJ, with the low CE of the Jib, I would go back to the original
design water ballast only, but I would add the cabin, and keep the
sponsons, even though they look odd. With a 10hp 4 stroke, water
ballast and the easy to manage Jib only rig, it could be fun, cheap,
and easy to motorsail with much more manageable trailering and storage
than an 8' wide catamaran.
So, whatcha think?
> So, whatcha think?Why not use one or two crab claw rigs? They lift the hull rather than
add downward pressure like most other rigs, and this would improve fuel
efficiency by making the boat lighter.
- Hi Don,
my two cents worth. I agree with you and think the concept is a
worthy one, however the rig may be best left with dipping (SMS FMS),
or balanced (MJ) lugs as originally chosen. Bolger went with these on
bigger boats of similar motor-sailer, or powered sail-assisted
passage intentions too, like on his own RESOLUTION, and the REIVER
recently posted about here.
These four-sided rigs are unstayed, with an easily lowered mast that
makes riding out or motoring into a blow respectively more relaxed or
fuel efficient. Also, any large true lateen rigs I've seen have been
The rigs JG has shown aren't lateens however. They are staysails (big
jib-like sail on rear set mast) with some similar desirable
attributes of lateens in being a lifting sail, with a relatively low
CoE for their size when fully deployed.
Most photos I've seen of large lateen rigs reef to the yard; this, I
think, due to it just being easier to tie the heavy materials of old
to the lowered yard before re-hoisting, and the requirement to keep
the decks free. JG's staysails are also shown furling upwards to to
the stay. I see some issues here: the masts will be harder to design
for the benefits of lowering them and the rig out of the wind
altogether; the weight of the sail is raised aloft as reefing
progresses (this may reduce rolling however, and even capsise by
increasing the moment of inertia); and the CoE is raised with that
reefing, when ideally it would be better lowered.
Another attribute of the staysail is just that: it needs staying. I
realise that JG has shown only sketched ideas, but IMHO there is
rather insufficient staying shown - take a look at Bolger's STAYSAIL
CAT (BWAOM, p149), or his staysailed CRUISING CATAMARAN (Derek
Harvey's book or MAIB Vol9 N013) to see how much staying is required
to stiffen the mast! The staying and stiff mast are required in turn
to tension the luff.
All that staying tension places great compression loads on the mast
which the hull must resist - or the mast will be driven through the
bottom, or the hull will "banana". This extra hull strength in turn
may require the hull to be considerably heavier (and more costly in
build and fuel) than otherwise.
The common bermudan rig with main furled and poled out twin jibs from
the single forestay is a well proven self-steering down wind cruising
type. The lug may require just that bit more watching, but simple
sheet self steering would even relieve much of that. Big lateens have
to be watched carefully down wind as an accidental uncontrolled gybe
can be disasterous.
The lug and lateen are good reaching and not bad to windward.
However, a lot of the above may not apply to your or JG's sail assist
if the wind is often with you. The twin staysail rig shown by JG may
not require all that staying, with the other inherent acccomodations
I've mentioned, if it is absolutely to be used only for dead down
wind work. If this is all it's to be used for then it won't matter if
the luff sags somewhat, but sail assistance is given up for anything
more than a very broad reach off the true wind. This rig may just be
for the most refined of gentlemen ;)
--- In email@example.com, "donschultz8275" <donschultz@...>
> So whatcha think?
> The neat thing I am writing about is that Jeff Gilbert has, in the
> Yahoo group jgbuilders photo section, sketches of a couple of his
> cats, Gravel Truck and Gumboots, using what he calls a lateen rig.
> sets the mast (masts) rearward and rigs a jib to it. The sail is
> loose footed (no boom) and is intended for downwind runs only. He
> suggests setting 2 of them, side by side, on his catamarans. Makes
> sense based on his note below...
- Hi Graeme,
> All that staying tension places great compression loads on the mast...snip...
> which the hull must resist - or the mast will be driven through the
> bottom, or the hull will "banana". This extra hull strength in turn
> may require the hull to be considerably heavier (and more costly in
> build and fuel) than otherwise.
An excellent example of this is the America's Cup yacht that literally
snapped in two and sank in seconds several years ago. I can't imagine
wanting to pay for and maintain all of that rigging on a cruising boat,
especially since one failure anywhere in the rig of even a single
component could cause the whole thing to come down. I would love to
try out a dipping lug someday.
> An excellent example of this is the America's Cup yacht thatliterally
> snapped in two and sank in seconds several years ago. I can'timagine
> wanting to pay for and maintain all of that rigging on a cruisingboat,
> especially since one failure anywhere in the rig of even a singleAnd here's the story:
> component could cause the whole thing to come down. I would love to
> try out a dipping lug someday.
Looks like I was off a bit - it took all of a minute and 40 seconds to
- --- In firstname.lastname@example.org, Kenneth Grome <bagacayboatworks@...>
> Why not use one or two crab claw rigs?The prime argument against about any other rig is that it adds
additional spars to buy and handle, and learn how to use.