On Tue, 23 Nov 2010 06:15:07 -0500, Wayne.B
wrote:

On Tue, 23 Nov 2010 17:46:50 +0700, Bruce
wrote:

Out of curiosity, why chain the shaft? Are you running on one engine?
And, if you are how is it working for you. I tried it and it simply
dropped the speed by about half :-(

On our boat we can improve fuel efficiency by about 25% running on a
single engine assuming a speed of no more than about 1.1 SQRT LWL.

We have Detroit 6-71 2-cycle diesels which are not efficient at low
speeds. Running single engine gets operating RPMs up to a normal
level. This is useful on long passages in relatively light winds and
calm seas. If the wind kicks up we need more power to maintain speed
and stability.

I've got littler engines and at cruise are running about 2,000 RPM on
both. Cutting one engine reduces speed by about half.

But you have, I believe a Grand Banks, which has a semi-planeing hull,
I think the company calls it, that can benefit from larger engines. My
boat is a displacement hull so additional H.P. isn't going to make a
vast difference.

You say "maintain speed and stability", do you have active
stabilizers?

Cheers,

Brice