I tend to agree that the outboard option will get you on the water earlier. It has the added advantage of being fully removable for service etc.
As a financial option it is certainly the cheapest.
As a building option it is the easiest
An interesting quirk with the rudder system is that if you split the direction you can very easily crab at 45deg(both rudders pointing the same way)
I was dumbstruck when I first saw rob do it on Harry.
I'm not aware if this is possible on the bigger versions but it makes docking a breeze(even with a single outboard)
If you have twin outboards you won't need a bow thruster anyway.
If you have ferrys there of the cat variety they are great to watch and learn how to dock without any steering.
Bow thrusters? they seem to be mostly on big commercial boats here
I watched a 100ft sailing schooner dock the other day against a beam wind blowing 20kts
It only had a single prop and no bow thruster. The skipper did it with what looked like ease.
He took his time, did a dummy run to access the angles required, then proceeded to slot it into a marina berth only marginally wider than the boat(you could get off either side onto the floating dock)
My point I suppose is the skill of the skipper can sometimes make up for alot of additional things(albeit things that make a task easier)
One more suggestion if I may. Nozzel attachments for the honda prop will probably cure the grip in reverse problem.
Kind Rgs
Tony
----- Original Message -----From: jjtctaylorTo: harryproa@...Sent: Thursday, October 28, 2004 12:51 PMSubject: [harryproa] Aux Drives for Visionarry
Been so long nearly forgot my password !
With the progress so far with Johnnie's boat, the visionarry in
latest stage of development, the aux drive has left me with some
questions and possibilities for input from our distinguished
forum. Albeit a quiet forum.
Outboards is the current plan, a pair of 15 horse honda's which
is a highly reliable 4-stroke. Certainly the most economical
choice and most likely to succesfully get it in the water.
The question I have,... is there better choices ? Lot's of history
with swamped outboards and propulsion woes with prop out
water in sloppy seas. I find the outboard closest to the WW hull
most at risk since it is not really close to the hull itself but
suspended part way across the beam due the WW hull
expansion. Yes OB's are a workable solution in moderate seas,
and perhaps a little awkward with initial manuevers in close
marineas cause the motor is not evenly spaced across the
beam, but functional. Rob's & Mark's plan includes 24 hours of
fuel aboard.
As food for thought to kick off the discussion I suggest a single
electric drive near the LW hull either as outboard or extendable
from inside the LW hull. Must be kept close to the hull,
upstream of the rudder to insure better helm control and the prop
stays in the water. At the other end would be a bow thruster
likely just aft of the leading rudder. An electric drive is sufficient
to replace both outboards (an equivalent 20-25 HP diesel) and
slow speed maneuvering can be deftly handled by the bow
thruster.
Anybody ever had a bow thruster ? Some issues remain such
as the thruster tube nacell, will it cause excessive drag in a
bi-directional shunting kind of mode ? There are retractable
options but much more costsly than an electric thruster and 2
batteries. (est 210-220 Lb force required)
Taking input, preferences, previous experience, or technical
saavy !
Regards,
JT
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