[MHml] [Harrys, heavy weather and jordan drogues
proa at iinet.net.au
Wed Nov 29 14:00:07 EST 2006
Good advice, thanks. The boom with the sail furled on it will hopefully do
the job, although it will require a huge lump of ballast to move the cog
forward of the rotation axis. What is likely to happen if the cog is aft of
this? In conditions bad enough to not have any sails up, I will have a
drogue (the only piece of safety equipment which I consider necessary but
the committee doesn't) out, so the boat should be bows into the waves and
----- Original Message -----
From: "Tom Speer" <me at tspeer.com>
To: "Informed discussion of multihull issues" <multihulls at steamradio.com>
Sent: Tuesday, November 28, 2006 2:39 PM
Subject: Re: [MHml] [Harrys, heavy weather and jordan drogues
> rob dalton wrote:
> > ...Not sure about having the wing masts in a blow ....
> It may be useful to have some sort of tail you can attach to the mast to
> make it weathervane when under bare poles. I realize just going to the
> lee hull and messing with something like that is going to be very
> difficult. A wingmast that flutters in a high wind can produce a huge
> amount of drag and have the windage of a round section much bigger than
> the thickness of the mast - maybe even an effective diameter greater
> than the chord of the wing mast. But if you can keep it feathered, the
> wingmast should have far less windage than a typical mast. However, it
> must respond rapidly to gusts - if it lags, the lift will be
> considerable. Just having the pivot ahead of the aerodynamic center of
> the mast is probably not going to be stable enough or damped enough.
> It's also important that the mast be ballasted so its center of gravity
> is on or ahead of the pivot axis.
> Tom Speer
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