I have considered the same thing. Can't find anything retractable that I
would consider a long term propulsion rated device. Thus a permanent
sail drive install of either electrical or diesel inboard have survived
sufficient test of time. But we agree minikeel essential to protect the drive
leg while addressing the leeway issue and rudder control.
Electrical is nice as it could be applied in a mode to regen the battery bank,
or run with very modest thrust as a motorsail. Motorsail is the method most
commonly applied by electric propulsion as it takes some of the surge out of
the puffs and minimizes the full drag impact of the prop. Also nice is electric
is down ready to go with no warm up. Crisis knocks and the aux is
prepared to move you, now!
But diesel would be OK too.
Not sure the retract functionality is worth the cost or complexity.
The necessity for leeway control does make the prospect for permanent
propulsion within the lee hull more appealing. Agree too with the
analysis that CLR is moving around needs to be better localized at all
points of sail. AS a cruiser I don't want another "thing" to be managed on
every shunt.
Now option #3 is saildrive for main aux, AND retractable electric bow thruster for
maneuver, like swing thruster and others. Prices have dropped on those due
to competition. Then you can really have some fun.
JT
--- In harryproa@yahoogrou
>
>
> One thing I have debated for a while is going with a propulsion-rated
> retractable thruster in the lee hull for the boat's motor.
>
> On one hand, I realize that this carries a $10,000+ penalty when
> compared to outboards, as well as some weight (once you figure in a
> genset and any propulsion batteries).
>
> On the other, it would have a number of benefits:
>
> - Convenient collapsing without having to worry about 000 cables,
> outboards, or other apparatus. Everything could be in one hull, with
> just house power going to the windward hull.
>
> - A highly cavitation-resistan
> beaten up or swamped by waves or chop.
>
> - The ability to drive forward or reverse without issues.
>
> - The option of charging batteries, either propulsion or house, while
> under sail.
>
> - The option of using diesel, or fuel cells in the future, instead of
> gasoline.
>
>
> But retractable thrusters are expensive, and they likely won't take
> very well to grounding or running into logs.
>
> A mini keel could be a nice way of making sure there's something
> sturdy to take impacts that would wipe the thruster out. There could
> be either two mini-keels in tandem, each with its own foil shape, with
> the thruster in the middle, or the keel could be one piece with the
> thruster angling out to windward.
>
> There would be less need for a keel if the boat had a deeper draft and
> the thruster could poke out above the hull bottom on the side, but
> that's not likely to happen with a proa that has any reasonable performance.
>
> - Mike
>
>
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