Concept Boat competition
Comments submitted between
18th November 2000 and
Ten people completed the questionnaire during this
were male with ages ranging from 18 to 59 years
(mean age 37). Two classified themselves as beginners, four as
intermediate, and four as expert sailors.
about existing sailing rigs
|"Windsurfing rigs - Lots of fun.
Getting better all the time with weight reductions and a 'smoother' feel
due to better designs (plan form, flexibility, etc). They look good too
but there's no doubt about the fact that they are far to expensive. Also
the happiness of manufacturers to satisfy whims, rather than design
faster sails, is holding the sport back. Not my words, but those of Ken
Black (Tushingham sails and formerly North)."
"I have a number of boats. The easiest to use is a gaff sloop
because it is so easy to hoist and lower the main, although reefing is
exciting and windward performance is not brilliant. The hardest to use
is a fully battened high aspect Mylar sail on a catamaran, because it is
difficult to hoist, and has no reefing, but I don't mind because it
works very well. On our most recent 6m cat, also hi-aspect Mylar, we
have slab reefing which increases the range of true wind speed we can
operate in but the mast, being aluminium, is very heavy at 21kg. I would
like a carbon mast to make rigging the boat easier. I am completing the
write-up of a thesis on Chinese fully battened lug sails
("Junk" sails), and have some experience of them too. Done
well, they offer a number of advantages for long distance/short handed
cruising. Done badly they are a nightmare!"
"Laser - so crap materials -expensive - but they look all right
"Too heavy, too complicated to raise (mast), sails OK"
"Heavy, brings too much forces in the boat, aerodynamics could
"Could be improved."
"Takes 15 to 30 minuets to set up. Hard to rig when winds are
high. Difficult to transport long mast."
"Too conventional, too expensive."
do you think of the Transition Rig idea?
|"I'm studying at Oxford for a PhD in
the biomechanics of animal flight. I carry out wind tunnel experiments
to visualise the flow around insect wings by looking at the deflection
of smoke as it passes over their cambered surfaces. The concept that we
can design BETTER aerofoils than insect wings, the smallest, smartest
aerofoils is a little arrogant - they've been evolving for 250million
years! BUT we can learn a lot. Why engineers have not turned to
biomimetics (copying nature to solve engineering problems) before is a
mystery. After all, we want high lift structures, ideally a thin
membrane supported by lightweight battens that deform passively
according to external forces. The asymmetric twisting and necessary
alterations in camber are modelled perfectly for us in nature. So to
answer the question, yes, I like the idea."
||I believe many engineers and architects
have taken inspiration from Nature in the past, and no doubt will
continue to do so. However, I think understanding is essential - copying
in the absence of understanding may not be effective. Good luck with your research - we shall look forward to
hearing about your findings!
|"Interesting. I would like to make
some comments - I hope they don't sound too negative, but they will need
to be addressed.
1. The Market
From your replies to some of the comments already posted it sounds as
though you're not yet aiming at the racing market. It seems to me to be
an (unfortunate?) fact that sailing boat development is driven by
racing, with innovations trickling down to the cruising sailor. Since
the transition rig looks as though it contains some sophisticated
engineering (e.g. highly loaded carbon joint components), it is likely
to be expensive. This would not be a problem for racing but for, for
example a sailing canoe for pottering/exploring lakes and rivers (where
I think it would be great), cost and complexity may be a problem. If I
could build a small, 6 sq m Transition rig from bamboo and plastic
tarpaulin for a canoe that I could repair myself, I would be greatly
encouraged. I suspect the market for non-racing, expensive small sails
to be very limited. Demonstration of a performance advantage in an
appropriate development class (Redwing? Moth?) would, in my view, be the
best way to go.
2. The Concept
is definitely worth pursuing. As some of your correspondents have
indicated, there is a need from the high performance/skiff sailors for a
rig with greater tolerance to wind fluctuations than currently
available. A sail that can give a limited upper heeling moment by
lowering C of E yet increase the forward component of sail force in
gusts is a goal that has so far only been met by variations in sail
twist (and reefing, of course!). The Transition Rig may take these ideas
|Your comment about performance as a
driving force in rig evolution is an important and valid one. We shall
need to pay attention to this factor while developing the transition
rig. However, our market research has shown that the other qualities of
the rig such as adaptability in use and foldability are also of
interest, particularly to less competitive sailors.
We are looking into the possibility of
making simplified versions of the transition rig for smaller-scale
applications such as sailing canoes and kayaks. It would be pleasing to
be able to do this using readily-available materials of the kinds you
have mentioned in order to keep costs down.
|"Been needed for teaching sailing
|"A bit weird - I'm not sure how well
the windsurfer type boom thing would work on a dinghy."
||Whichever boom arrangement is used on
the dinghy version, it has to be able to support the trailing edge of
the sail away from the mast, and also allow the rig to fold when
required. The wishbone-boom currently used works well, but we shall
probably experiment with other types of boom to see if there is a better
|"If it works, it will be the best
concept, I have ever seen. I have seen it somewhere else :-) (eg.
birds), but learning from mother nature is the best way to learn:
||Yes, all credit to the birds and bats
|"Looks interesting. Will it look so
nice after sailing a season North Sea coastal cruising?"
|"I like it, but have some performance
|"I think it is a great idea. I'd like
to see you consider also incorporating controllable mast bending
(cupping) perpendicular to the planform, to enable active control of
spanwise twist distribution, camber, sail tension, and aeroelastic
number. This goes a long way toward overcoming some of the problems
associated with 'stretchy' membranes, and allows the 'stretchy' sail to
perform pretty well over a much broader range of speeds and loadings,
although I wouldn't speculate that it could perform as well as an
inextensible sail under perfect, invariant conditions. I work with the
biomechanics of a couple of large, late-Cretaceous pterodactyls which
used a somewhat similar wing with a visco-elastic membrane and short,
intercalated reinforcing fibers. They were marvels of efficiency. Quetzalcoatlus
northropi (the larger of the two) had a primary wing area of about
7.3 square meters with intercalated aktinofibrils in the outer wing that
could redistribute some local membrane compression loads, allowing the
membrane to fly at a reduced aeroelastic number before initiating
wrinkling or fluttering. The fibers also worked to allow active control
of aft camber."
||The two parallel struts that form the
middle segment of the transition mast are able to rotate in relation to
each other, in a similar way to the movements of the radius and ulna of
the forearm when we pronate and supinate our hand. This rotation has a
profound effect on the overall geometry of the mast, enabling a shift of
the 'cupping' effect that you describe from one side to the other when
I am quite envious of the ability of Q. northropi
to actively redistribute tensions within the wing membrane and reduce wrinkling when
the geometry changed. Modern-day bats have a similar ability. I
understand that active synthetic membranes are being developed, but I
have not yet been able to try them.
you buy a Transition Rig?
(Two respondents simply said "yes".)
|"That depends on the performance and
price. Do the joints and elastic sail cloth add a lot to the
||The transition mast is more complicated
than a conventional mast, so a weight penalty is probable. That will have to be minimised by careful design and
choice of materials. It should be possible to identify an elastic sail cloth that is
no heavier than conventional non-stretch sail materials.
"No I'm a student I avoid buying things at all costs!"
"I have to read all the infos first, but in general: why
"Wait and see what brings the real sailing days."
"Yes, but I want to try it first."
"If it works."
"If I were a windsurfer I would."
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