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Capt. Neal® January 5th 05 04:20 PM

Hey all you stupid people who don't have a clue about aspect rations
 
Hey all you stupid people who don't have a clue about aspect rations, read this:

Aspect ratio:
"The rig aspect ratio affects the pointing ability of the boat. A taller rig produces more drive at a given wind angle and for the
same sail area than a lower one. Try a very high aspect ratio P= 17.35 m E= 5.00 m, and compare with the default rig (Reset). There
is a catch with high aspect ratio - heeling moment goes up - this puts a practical limit to the tallness of the rigs we use on
contemporary boats. Low aspect ratio also performs better off wind."

In the case of "the Bat" is is clear it is always going upwind at speed. It does not have to worry about heeling as it is a
hydrofoiler and the foils can be adjusted to compensate for heel. It needs higher aspect ratio sails than shown in the picture and
the head of the sail should not be flat like that because it produces a large tip vortex which causes drag.

CN


Jeff Morris January 5th 05 07:37 PM

Capt. Neal® wrote:
Hey all you stupid people who don't have a clue about aspect rations, read this:

Aspect ratio:
"The rig aspect ratio affects the pointing ability of the boat. A taller rig produces more drive at a given wind angle and for the
same sail area than a lower one. Try a very high aspect ratio P= 17.35 m E= 5.00 m, and compare with the default rig (Reset). There
is a catch with high aspect ratio - heeling moment goes up - this puts a practical limit to the tallness of the rigs we use on
contemporary boats. Low aspect ratio also performs better off wind."

In the case of "the Bat" is is clear it is always going upwind at speed. It does not have to worry about heeling as it is a
hydrofoiler and the foils can be adjusted to compensate for heel. It needs higher aspect ratio sails than shown in the picture and
the head of the sail should not be flat like that because it produces a large tip vortex which causes drag.

CN

Its pretty clear you know nothing about high performance boats. Here's
a proper picture of the bat:
http://marine.bdg.com.au/spitfire_dimensions.html

I find it hard to call that a "low aspect" rig.

Heeling is indeed a big problem with hydrofoilers - that's why they use
the twin rig.



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