DSK wrote:

Anyway, long narrow boats like the IACC class and the old 12s too
tend to sail at higher angles of heel than more normally proportioned
boats. I still think 30 degrees is a bit of an overstatement.




Nav wrote:
Wot only a 'bit' now is it? Just yesterday you rubbished it! Doug,
lots of boats are only fully powered up at 30 (or more) degrees heel.


OK, I am still not sure what you mean by "powered up." It sounds to me
like you are relishing the feeling of heeling too much. It's fun, but
it's really not fast.

.... Of course as a dingly sailor you wouldn't know that but it's
really true.


Spoken like one whose experience in racing class dinghies is limited to
embarassing capsizes within 100 yards of the club dock.


Let me paint a typical picture for you: At that 30 degrees heel the
boat is alive and really punching through waves to windward.


At 30 degrees heel, the boat is heeling too much. It is "punching"
through waves because the hull presenting a set of awkward angles. Other
boats have depowered a little and are going faster.

Have you done any big boat sailing or been in a race in windy
conditions? Why not read the book whose URL I posted and then come back
on it. Better yet go back to the classic literature and look at the
tests of the Gimcrack. She was fastest at 30 degrees and was no faster
at 35 degrees. That's still a correct rule of thumb for most fast
cruiser racers today.

Perhaps Donal would like to post the figs. for his boat -if he's got them?

Another slam dunk.

Cheers

Nav wrote:
Have you done any big boat sailing or been in a race in windy
conditions?

Why, of COURSE not, Navvie. Never!

But then you are a liar, so you think I must be one too...


.. Why not read the book whose URL I posted and then come back
on it.

So you're saying that you base your judgement solely on what you've read
in books?

... Better yet go back to the classic literature and look at the
tests of the Gimcrack. She was fastest at 30 degrees and was no faster
at 35 degrees. That's still a correct rule of thumb for most fast
cruiser racers today.

Not in my experience. Most boats like about 12 degrees of heel. The
Soling (a relatively narrow boat) sailors I know say their boats like
18. I would generalize to say that narrower & heavier boats like more
heel, but in cases where the keels and/or rigs get dramatically less
efficient with increased angle, it would be beneficial to take some
serious sailing tests to determine the desirable range of heel for most
conditions.

One big limiting factor is the helm. Increasing heel increases weather
helm. That has to be counteracted with the helm. A slight weather helm
is nice, a lot is bad. It's slow and it can make the boat hard to control.


Perhaps Donal would like to post the figs. for his boat -if he's got them?

Another slam dunk.

Maybe you should be less concerned with "slam dunks" and more concerned
with actual sailing? Just a suggestion.

Fresh Breezes- Doug King

DSK wrote:

Nav wrote:

Have you done any big boat sailing or been in a race in windy
conditions?


Why, of COURSE not, Navvie. Never!

Well it's good to know my suspicions were correct.


So you're saying that you base your judgement solely on what you've read
in books?

It was you that was seeking references wasn't it? Don't you like
definitive references that support my views? How strange. Perhaps you
are the sophist Jax suggested?

Cheers

Nav wrote:


DSK wrote:

Nav wrote:

Have you done any big boat sailing or been in a race in windy
conditions?



Why, of COURSE not, Navvie. Never!


Well it's good to know my suspicions were correct.

Just as correct as most of your other assertions.



So you're saying that you base your judgement solely on what you've
read in books?


It was you that was seeking references wasn't it? Don't you like
definitive references that support my views? How strange. Perhaps you
are the sophist Jax suggested?

Because I show that you are wrong, does that make me evil or sick in
your opinion? Besies, if I am as stupid as you say, then I could not
have the intelligence & subtlety to be a sophist.

DSK

DSK wrote:



Not in my experience. Most boats like about 12 degrees of heel. The
Soling (a relatively narrow boat) sailors I know say their boats like
18. I would generalize to say that narrower & heavier boats like more
heel, but in cases where the keels and/or rigs get dramatically less
efficient with increased angle, it would be beneficial to take some
serious sailing tests to determine the desirable range of heel for most
conditions.


Bluster all you like but 30 degrres for max boat speed is still quite
usual. How about a designer of the Volvo 60:

"Roll, baby, roll …
Volvo 70’s must be designed to stringent large-heel-angle stability
criteria. While a canting keel increases stability (or righting moment)
dramatically under

typical sailing conditions (say 30 degrees of heel),

its offset CG actually works against a self-righting tendency at large,
knockdown heel angles. Accordingly, Volvo 70 Rule developers have
closely examined limitations on hull displacement and beam that affect
form stability, with additional limitations on keel weight and keel
swing angles. Each yacht shall have a designer-calculated limit of
positive stability greater than 115 degrees, with appendages positioned
in a worst-case scenario. In addition, each boat must successfully
self-right from a 180-degree inversion using only manual power to
articulate the keel."

http://www.perrottidesign.com/new_Volvo_Open70.html

Cheers

Nav wrote:
Bluster all you like but 30 degrres for max boat speed is still quite
usual.

So far, you seem to be talking about IACC boats and 'Round-the-world
racers.... now you're generalizing to all boats? These are pretty
specialized designs.

Find a quote from a racing skipper who says specifically, "Yes, we won
because we kept the boat at 30 degrees heel and more." Then maybe you'll
have something. If you are a member of a sailing club you can ask
around... oh wait, that's in the real world...

For the following quote, I'll give you 2 points (although Bart is the
official scorekeeper, he'll have to verify it) it still proves nothing
about the way 'most boats' sail IMHO.



....While a canting keel increases stability (or righting moment)
dramatically under

typical sailing conditions (say 30 degrees of heel),

its offset CG actually works against a self-righting tendency at large,
knockdown heel angles.

True because the canting keel will have similar CG geometry to a dinghy
with a hiked out crew... oops wait...

.... Accordingly, Volvo 70 Rule developers have
closely examined limitations on hull displacement and beam that affect
form stability, with additional limitations on keel weight and keel
swing angles. Each yacht shall have a designer-calculated limit of
positive stability greater than 115 degrees, with appendages positioned
in a worst-case scenario. In addition, each boat must successfully
self-right from a 180-degree inversion using only manual power to
articulate the keel."

This is rather ironic, Navvie, they are talking about LPOS not max
speed. Another oops?


http://www.perrottidesign.com/new_Volvo_Open70.html

Anyway thanks for the link. Cool pictures, I am looking forward to
seeing more forward-foil boats sailing.

Fresh Breezes- Doug King

DSK wrote:



... Better yet go back to the classic literature and look at the tests
of the Gimcrack. She was fastest at 30 degrees and was no faster at 35
degrees. That's still a correct rule of thumb for most fast cruiser
racers today.


Not in my experience. Most boats like about 12 degrees of heel. The
Soling (a relatively narrow boat) sailors I know say their boats like
18.


I guess you would not have overtaken the race leader -look at this:


http://www.sevenoceans.com/SoloAroun...Leg1/Day30.htm


Cheers

Nav wrote
I guess you would not have overtaken the race leader -look at this:


http://www.sevenoceans.com/SoloAroun...Leg1/Day30.htm

Great pics. But again.. a special case. Those boats are more like scows.
Besides, for publicity shots they like to heel the boats 'way over. And
the boat in the top pic is certainly not heeling at any great angle. I
guess you have to be *very* selective in choosing examples that support
your contention?

Fresh Breezes- Doug King

DSK wrote:

Nav wrote

I guess you would not have overtaken the race leader -look at this:


http://www.sevenoceans.com/SoloAroun...Leg1/Day30.htm



Great pics. But again.. a special case. Those boats are more like scows.
Besides, for publicity shots they like to heel the boats 'way over.
And the boat in the top pic is certainly not heeling at any great
angle. I
guess you have to be *very* selective in choosing examples that support
your contention?


No, these boats are faster at 30 degrees of heel when beating as I keep
saying. Are your seriously suggesting you are a better racer than
Thiercelin who talk about being at a permanent 40 degree heel?

You are dead wrong on this one -admit it.

Cheers

Nav wrote:
No, these boats are faster at 30 degrees of heel when beating as I keep
saying. Are your seriously suggesting you are a better racer than
Thiercelin who talk about being at a permanent 40 degree heel?

Key- 'these boats'

You keep picking expamles of extreme type and saying this is how normal
boats sail.


You are dead wrong on this one -admit it.

Nope, so far you have provided some interesting pictures and some
exceptional examples, but for most boats that is far too much heel for
best performance. The fact that you *think* you are proving something is
really kind of amusing.

Fresh Breezes- Doug King