A Bermuda Sloop, and basicly all sloops should have a M/F ~1 since
everything else fast incease other backsides.

actually old photos of Bermuda Sloop rigs show a very long boom and a small
curved gaff at the top of the mainsail.

the tall narrow sloop rig is usually referred to as a Marconi rig, after the
early radio transmission towers held up by stays which the sailing rig
emulated.



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On 14 Oct 2004 21:34:36 GMT, Stephen Baker wrote:

Morgan O says:

The
minimum CE is when M/F = 1

Actually, geometrically speaking, it doesn't matter what the Main/Foretriangle
ratio is - the CE is always at 1/3 of the height of the triangle. THis works
for catboats and genoa-only boats.

Steve

Perhaps I make a misstake, but two equally high sails must make the bigghest
area AND much lower CE compared to a Cat rig

So, without checking it all that in detail I say you spread a misconception.

The CE gets LOWER with M/F=1 compared to the extreme M/F = 10/0 = eternity

Sails with the same aspect ratio understould.


Morgan O.

On Thu, 14 Oct 2004 17:38:06 -0400, DSK wrote:

Morgan Ohlson wrote:
OTOH, high aspect ratio rigs have a
number of drawbacks for small boats... they require a bit more fancy
engineering,


???

In order to gain any benefits from the higher aspect ratio, the sail has
to be more carefully designed & made, the mast has to be longer

Naturally ;o)

& shaped
for less turbulence over the forward part of the sail, etc etc. A high
aspect ratio sail is a (relatively) high tech tool. You did not see high
aspect ratio sails back in the old days because they did not have the
engineering nore the materials to make them stand and get the benefit.

When saying that you should state at which level you mean this becomes
nesessary.

Aspect Ratio? 3? 4? or 6?

A good aerodynamic rig is always a pleasure, but at which levels doesn't the
"old solutions" work at all?


a somewhat more complex & more stressed rig,


Taller mast???
CG rais???

Yes but there will also be more compression on the mast, more tension on
the shrouds, greater loads on all parts of the rig. Greater loads on the
hull too including heeling moment.

ABermuda sloop with M/F = 1 has the lowes mast per m2


What wou write is definitely right, but your quick jumps doesn't make sense.

OK, that's why I'm back trying to explain a little better. I am not a
good explainer, sorry.

No rig can be optimized for all occations anyway. What can be done is to
avoid silly arrangements with the rig choosen.

Yes, that is very true.


A Bermuda Sloop, and basicly all sloops should have a M/F ~1 since
everything else fast incease other backsides.

That depends on your goals. A lot of very practical sloops seem to to
have a luff/foot of about 1.5 ~ 1.8 sometimes more. Of course there are
those with shorter rigs & longer booms, many of them sail well too. It's
a question of getting the right sail area, the right foils, and putting
them in the right place on the hull.




Making a small jib you could just as well use a Bermuda Cat (no jib).

Not necessarily. A small jib is helpful in several ways, including going
to windward, handling the boat in a chop, and helping the boat maneuver.


Explain how a very small jib will improve on a decreased Cat. (same total
area and both correctly balanced to CLA)

Why insist on keeping area constant?

No, that is not for The design, but for the rational thinking and
understanding of how things relate to each other.

You can't describe something to another person, and in your head, without
telling changeing other stuff... then it becomes totally irrational (not as
a fact, but for all others to understand).

The only real acceptable reason to step away from M/F=1 is if a cuddy
doesn't allow one sail to stand low or if you must avoid some stayes and
must reduce one sail of structural reasons. ...which naturally should hav
ebeen taken care of earlier in the design process (in a perfect world).


My point is that jib can help very much under some conditions (for
example, helping the flow across the lee side of the lower portion of a
low aspect mainsail), it's handy for maneuvering, it looks nice, and it
helps stave off boredom. It does add to the cost though.

Probably a good point.



FWIW I don't like self tacking jibs except on racing boats where you're
likely to be very busy with other more important tasks. Self tacking
adds rigging & clutter that a cruiser would probably be better off
without. Plus, no self tacking sheeting arrangement sheets the sail
effectively for a wide range of courses, for example you can have it set
up for going cloe-hauled (the most common arrangement) and it's all but
useless on a reach... when a racing boat would be setting a spinnaker
anyway, but you probably wouldn't be.


"going cloe-hauled (the most common arrangement)" ? sorry, don't
understand.

If you set up the self-tacking jib so that it can be trimmed to be most
effective when close hauled, it will not be anywhere near as effective
on other points of sail. This doesn't seem to bother some people.


A self tacking boom arrangement attract me most. Someone called it "old
Petrus boom".

Never heard of that. Anyway, I hope this helps.

Some say that teachers learn as long as they have pupils, so I hope you
learn too.... )


Morgan O.

On 14 Oct 2004 21:32:17 GMT, Stephen Baker wrote:

Morgan O says:

I get a little tiered of those who call themselves designers and only whant
people to buy books or get stuffed...

If you'd like to pay the $50 per hour consultation fee that I usually charge
(and get), then I would be happy to entertain all your questions at great
length ;-)
However, if you are looking for free-ish info, then the book is as good as it
gets.

You know... usenet isn't really a market.

It's as simple as that!


I'm greatful for those who like a debate... but if anyone tries to embaress
me or others for not being educated enough before debating... he will get a
straight boot up his ass!

This is not an area ONLY for the already enlightened. It's as simple as
that!


Morgan O.

Morgan says:

You know... usenet isn't really a market.

Nor is it a place where advice must be freely given to all that ask. I am not
here to sell anything. Nor am I here to give free advice to those who complain
when I suggest that a book might be the best answer.

This is not an area ONLY for the already enlightened. It's as simple as
that!

That is very true - but it is an area where a great many people are giving away
the information that they usually get paid to know, for free.
Why do I offer free advice on Usenet, when this is my business and what puts
food on my table? Well, that's a damn'd good question right now.

Steve "think about it...."

Morgan Ohlson wrote
SNIP:

This is not an area ONLY for the already enlightened.

SNIP
Morgan O.

However, those who are resolutely UNenlightened and don't recognize good advice
when it's offered won't get good answers after a while.

Morgan Ohlson wrote in message ...

I get a little tiered of those who call themselves designers and only whant
people to buy books or get stuffed...
Morgan O.


Holy crap! You come here with basically nothing asking for free help.
You get two professional working designers helping you on your threads
and you respond with this? If I were Evan and Steve, I would tell you
to get stuffed... And to make my personal observation watching your
threads for the last few weeks, I would note that even folks like Monk
and Gardner say that is will be a matter of luck if you can get a
first try at balancing a sail on a new boat right the first time, even
with all the calculations. And screw me, but I hope you end up with a
hard lee helm. Spoiled children, geeeeze...

Yeah, the Backyard Renegade...

On 15 Oct 2004 10:00:40 GMT, Stephen Baker wrote:

Morgan says:

You know... usenet isn't really a market.

Nor is it a place where advice must be freely given to all that ask.

Ahaa, so we started flaming now!?

So utterly low.


Morgan O.

Morgan Ohlson wrote:
*** Jib size or Main/Foretriangle Ratio ***

If very theoretically 1 (equally large) must be the best. It lowers
(vertically) the CE to minimum and the shortest possible mast is needed.

1. What says that the main should be bigger?

2.Some boats have M/F-ratios of 4. That seems really stupid.

3. Is a self tacking jib a matter of importance when regarding the
M/F-ratio?

Ratio itself is just a number which in itself is not important.

Self tacking or not doesn't matter, really, except that self tacking
jibs must be smaller than the space in which they are flown, as the
jib club foot must pass between the headstay gooseneck and the mast.
It may also be required to pass in front of the foreward shrouds,
if other considerations permit using the club somewhat off the wind.

Interference with the pulpit bases while winged out is a
consideration. I prefer the longest possible club, so as to enable
flattening the jib in a constant way wrt the actual sheeting angle,
critical to good windward speed. All that depends on the geometery
and the system employed. The main advantage I find with a self
tending jib is really sheeting angle. Inboard sheeting angles permit
much better pointing, superior performance over a big baggy outboard
genny when there is enough apparrent wind. Off the wind I lower the
club and use regular outboard sheets, which are always attached even
when both are lazy, when using the "automatic" rig.

The actual ratio between sails isn't the key, here. It is a question
of balance overall and the relationship between sails in total verus
keel and rudder. A small jib may well improve weather helm over
going without.

Improve means reduce or increase, depending on your circumstances.

Terry K

On 15 Oct 2004 06:24:48 -0700, (Backyard
Renegade) wrote:

Morgan Ohlson wrote in message ...

I get a little tired of those who call themselves designers and only want
people to buy books or []...
Morgan O.


Holy crap! You come here with basically nothing asking for free help.
You get two professional working designers helping you on your threads
and you respond with this? If I were Evan and Steve, I would tell you
to []...
.....
Yeah, the Backyard Renegade...

What he (BR) said....

Brian W