On Sat, 24 Nov 2007 08:03:34 -0500, "Roger Long"
wrote:

Another nice thing about a shaft brake. You can hook it into the
transmission shift mechanism so it engages whenever you shift to neutral.
This lets you shift from forward to reverse faster and with less wear and
tear on the clutches.

Shaft brakes are also nice to have if you need to be towed. I've heard of
lots of cases of people down in the engine room trying to wrap chains and
ropes around their spinning shafts to save the transmissions while being
towed home.


This "running one engine to save fuel" story has been popular for
ages, but I have always wondered about it. If it takes X horsepower to
drive a hull through the water at Y speed then is there any real gain
in running on one engine since, assuming no loss in speed the single
engine must produce the same horse power as the two had previously
done. And the drag on the non powered propeller needs to be included
in the equation.

At least in my own case, twin 60 HP diesels with Hurst transmissions,
I find that shutting down one engine and locking the propeller on the
shutdown engine results in either losing speed or using a lot more
throttle.

I can't give any definitive figures but running both engines at a
reasonable speed seemed to give the best ratio of distance/fuel.

Have there been any studies made of shutting down one engine? I know
that Beebe published some RPM/Miles/fuel consumption charts but those
were for a single screw drive.

If there is any published data available it would certainly
interesting to know.


Bruce-in-Bangkok
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from address for reply)