Subject: Re: [harryproa] Re: under over buoyant or weight
From: Rob Denney
Date: 9/16/2011, 10:31 PM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

BD's lee hull is huge compared to any trimaran lee hull, and plenty big enough for the immersions it sees.  There may well be an optimal cant angle for a particular boat speed, but when the boat has to perform from 0-20, it has to be an average.


rob

On Sat, Sep 17, 2011 at 1:55 AM, tsstproa <bitme1234@yahoo.com> wrote:
 

In the drawing the vertical line above hull represent the rotation of leeward hull due to either sail induced heeling or improperly aligned hulls. I can show incremental heel angle on paint for any unless I draw each one. Still referring to Blind Date and its smallish looking leehull.

Put a up another diagram in same folder see both set at vertical static positions no induced preset canting. Each are set as loaded ready for sailing.
Each leeward hull in diagram will have a different canted angle when under sail heeling loads while sailing at same speed.

When at desired speed range say 16 knots the force exerted on leeward hull requires buoyancy to restrict further sinking/squatting to reduce further canting of hull to maintain optimum performance. If you are already at max canted angle due to low buoyancy or misaligned hulls then performance of hull/boat will suffer.

Todd



--- In harryproa@yahoogroups.com.au, Rob Denney <harryproa@...> wrote:
>
> Sorry,which post does this refer to? All harrys so far have had pretty much
> level decks and vertical masts, apart from one of the early prototypes where
> it was canted to windward. Good for racing, not such a good idea for
> cruising (Sail force increases as the boat heels) or light air (sail falls
> to ww). The 15m in the shed at the moment has a canting/raking rig. will
> be interesting to see how it works out.
>
> rob
>
> On Fri, Sep 16, 2011 at 12:09 PM, tsstproa <bitme1234@...> wrote:
>
> > **
> >
> >
> > Hey Rob this is what I meant have a look in photo's under forces at play
> > just a thought the vertical lines show rotation due to precanting.
> >
> > Some might say INDUCED positive / negative for anticipation of.
> >
> > Todd
> >
> >
> >
>


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