[Public-List] hull speed

[Mike Lehman]

Scary times huh George? But consider this...when over-powered by sails , you 
are healing over 20, 30, 40 perhaps more degrees. This increases your LWL 
and reduces your wetted surface. In fact, when the boat is laying on her 
side she starts to take on the properties of a planning hull, which is why 
she is able to achieve the speeds under sail. I wouldn't recommend reaching 
with a spinnaker in 35 knots, it's too....

-----Original Message----- 
From: George Dinwiddie
Sent: Monday, November 14, 2011 8:46 PM
To: Alberg 30 Public List -- open to all
Subject: Re: [Public-List] hull speed

Jeffrey,

On 11/14/11 6:45 PM, Jeffrey wrote:
> Gordon,
>
> With respect, I don't think it is possible to power an A30 hull to 7-8
> knots. Hull Speed is somewhere around 6.2 knots. My 20hp can power the 
> boat
> to just over 6 knots at max rpm, but the noise and fuel consumption is
> wicked. I've hit 7 knots and more for very brief periods of time under 
> sail
> when hit with a gust, but never under power. These speeds clocked with 
> GPS.

Oh, you can go faster than hull speed.  It's just that the power
required to do so goes up quite fast as the boat starts climbing it's
own bow wave.

I've been on an A30 going in excess of 10 knots (sometimes pegging 12 by
the knotmeter), but they get pretty squirrelly with that much of the
boat out of the water.  This was night-racing on Kittwake in 40+ knots
going wing-and-wing with a reefed main and the #2 genoa poled out on the
spinnaker pole.  It tore the spinnaker pole track off the front of the
mast and the tiller head twisted off the rudderpost twice.

And ask Mike Lehman about the 10 knot spinnaker deathroll.

  - George

-- 
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   When I remember bygone days                         George Dinwiddie
   I think how evening follows morn;            gdinwiddie at alberg30.org
   So many I loved were not yet dead,           http://www.Alberg30.org
   So many I love were not yet born.                          also see:
                'The Middle' by Ogden Nash     http://idiacomputing.com
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