Subject: [harryproa] Rudder Harryproa
From: Doug Haines
Date: 4/4/2008, 5:48 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

Hi Rob,
 
I've built a few sorts, got Elementarry plans for another sort and seen a few more sorts but forget where I/we was going in the rudder department.
 
Summarizing current Doug view:
 
    No real problems, most of problems sorted out -
    -rudders are used one at a time only, because I can't steer two rudders together, the rudders don't rotate round the other way so you can't steer with the front one anyway.
    -the rear rudder is down but can and will kick up when coming in to shore/sliding over a sandbank, some elastic give lets it swing back a far bit first automatically on touching ground, the rudder wants to float up to the surface and unhooking the pull down lets it come up that far. Th epull up rope then lifts it up above the horizontal out of the way above the wave tops.
   - the forward rudder is now going to be the aft rudder, so shifting myself across to the the new aft end of the deck, I let free the pull up rope from its cleat and pull fully down on the pull down rope and hook the stick in behind its cleat blocks.
 
OK so better than it was, no real things problems, safe strong, fairly simple system.
 
What happens when going up to harry size?
 
- the rudders were designed to BREAK OFF at a pre-built weak point? I read this in the site I think.
-What I would like is to be able to sail Harry similarily to SideCar and not care if it goes from 6 feet deep to say 3 feet.
 
It is harder to steer when the blade swings back, but I still get over the and bank allright, then pull it down again.
 
If Harry rudders just lift straight up then there isn't too much diffrence in sailing with 3 feet rudder than 6 feet in that the bottom might stick up and still touch, so by breaking something. I can't imagine taking a dagger style Harry into any where shallow, thereby losing all the shoal draftness exceopt for coming in with just motors. Is this an expected sailing practice of most people - to only sail in deeper water, and only motor when in water less than I don't knoew exactly, when you aren't sure its deep enough for the 6 foot or whatever.
 
I'm distinguishing between marina to marina, deep anchorage/long tender journey cruising, and coming in to next to the beach ( where the shelter is the best). Plus sailing across short cuts or bays/ coastal sandy places which one might like to go to or through.
 
Just wondering if I can get something on a big scale to swing up, rather than breaking a pin every time grounding along the bottom. Of course my ones don't swing both ways so what does it need?
 
Thanks for your time and effort
 
Doug 

Rob Denney <harryproa@gmail.com> wrote:
G'day,

Blind Date is getting an electric motor this winter.  The 66'ter in Portugal and the 60' charter boat are both planning on having them as well. 

Putting them on the rudders solves the two way problem and gives amazing maneuverability.  Would only need one if it was powerful enough.   No real drawings yet, but the principle is a sleeve that slides up and down on the rudder blade with the motor attached to it.  Lift it clear of the water when not in use with a block and tackle, ease the rope to lower it.  Much cheaper and more reliable than the African Cats system.   Kicks up on impact and very accessible for clearing ropes and stuff off the prop.    Also (smug grin) not usable by boats without beam mounted rudders. 

Another version is the e jet  http://www.e-jet.org/html/typen.html 

regards,
Rob

On Thu, Apr 3, 2008 at 10:26 PM, chesapeake410 <chesapeake410@yahoo.com> wrote:
Hello,
I am planing on building a 12 m Harryproa and am thinking of using
electric pods. Pods would be mounted on swing arms similar to what
has been used on African cats. Take a look at the June 14,2007 press
release on Africancats.com website. Also check out RE-E-Power.com .
In the Re-E-Power Forum link in the photo section is a example of a
pod mounted to a long swing arm.

Has anything been done with electric power on Harryproa's ? I think
there was a recent reference to electric motors on rudders, does
anyone have more information or pictures on this.

I think a Harryproa would be unequally suited to a solar/battery
electric drive system since the sail is offset on lw hull. A solar
canopy over the seats a center area of boat would be less obstructed
by sail than a cattermaran.

The proa does have the problem of how to deal with going in both
directions with the electric drive. You could point one in each
direction and only use one in open water and lower both for
maneuvering in harbor or for extra power when needed. You could use a
prop designed for both directions but I do not know it it would be as
efficient as one designed for one direction.

I would like to hear any sugjestions and comments one this ?

One other concern would be the added weight of a battery pack which
could be as much as 1000lbs or more. I am hoping that newer battery
types will bring down the weight in the next few years to less than
600 lbs.
Valence Technology Lithium batteries would be great but the current
price is prohibitive. Firerfly batteries (a new lighter type of lead
acit battery) sound like a good bet but are not yet available. It
may be necessary to start with current lead acid and switch to
lighter batteries in the future. After Lithium batteries get
established in electric cars that will start coming out in the next
few years I expect availability and price to improve. I spoke with
Bob Lutz vic chairman of General motors at a special event a the New
York Auto show a week or two ago and he claims that they will have
the Chevy Volt in production by the end of 2010 ! It will run on
lithium batteries.

Thanks for any imput on this topic,

George Kuck
Chestertown, MD



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