[MHml] Bearing away in a gust ...

[multihulls at steamradio.com]

 ...snip....
On Thu, 01 Feb 2001 23:32:18 +1100 nudd
<nudd at ozemail.com.au> wrote:

> My rule of thumb for which way to turn: when
spin is up bear away.
> When spin is not up - luff up.  Learned this
when sailing 470 dinghies
> and have applied it to 20 yrs racing larger than
otb multi's.

Yes - I confess to finding the discussion so far a
little
mystifying, but that may well be to personal
ignorance,
& the application of that to my sailing !   So....

As far as bearing away in gusts goes, this is
something I would
*only* do sailing off the wind, ie reaching or
running.
If I was on the wind, I would *not* bear away in a
gust,
I'd do something else.

rgds Pete McD
... end snip ...

I am also a bit mystified about bearing away in a
gust in a situation where the boat is overpowered,

and burying a pontoon in a tri or flying a hull in

cat.  I am hoping that someone can explain the
physics of this.

It seems to me that the heeling forces are all a
function of the true wind and not the apparent
wind.
The apparent wind is a product of the true wind
and boat speed wind.  The boat speed wind is
mostly from dead ahead and has no heeling force.
The amount of heeling force is related to the
vector
of the true wind perpendicular to the boat.

To decrease heel one needs to decrease this force.

When the true wind is forward of the beam it seems

that one would need to head up, into the wind
more,
luffing up and that decreases the force (an
alternative
is to ease the main which also lessens the heeling

forces).

It seems to me that bearing away at this point
would
increase heel. When sailing deeper with the true
wind
behind the beam, then bearing away would decrease
this force.

If this reasoning is faulty I would appreciate
some
guidance before I get myself into a pickle.

                      Rod Tharp ( Strider - F-9A)