Others have mentioned commercial systems like Searay "Zeus" which is diesel powered.
I would have thought someone would have made an off the shelf version by now. There are definitely times when it would be handy just to have station keeping active while you work on something else.. especially if you are short handed.
--- In electricboats@yahoogroups.com, "leemurs72" <jt.yahoo@...> wrote:
>
> What you are looking for is called "station keeping" in autopilot speak. http://www.yachtingmagazine.com/article/Best-New-Autopilots has some tidbits on various autopilots. The ComNAV autopilots have station keeping abilities, but I think that requires a bow thruster...
>
> I am sure you could spoof a stay-put request by feeding a tight circle of waypoints to your autopilot over and over again. Of course, your anchorage neighbours would not be too pleased.
>
> How about adding a strain gauge to the anchor line feeding info to a computer which can then have the propulsion system stry to keep the strain within certain limits? this dumbs down the requirements and complexity a lot since there is no steerage involved and no need to coordinate control of multiple motors, just straight thrust with feedback from a strain gauge. It's a bollard pull. That could go a long way to improving holding and not consume too many watts hours. In bad conditions, it would certainly redus the stress of an already stressful situation.
>
> Mike, you were recently anchored and on board at the tail end of a hurricane. Would something like this have been useful to you?
>
> Cheers,
>
> /Jason
>
> --- In electricboats@yahoogroups.com, "Galstaf" <richard@> wrote:
> >
> > Thx for the heads up, Hans! Very good point. One other thing I thought would be useful for the articulating drive is the possibility of having a virtual (or active) anchoring system.
> > As the boat I am planning will have pretty substantial wind turbines/solar to keep the battery bank topped up and the motors powered (planning a 20kW system), I am hoping to either find a gps based system that one could basically tell the boat to "stay put", and every time the tide or wind push it out of its given gps position, it fires the directional motors to push it back into place.
> >
> > I don't know whether such a controller currently exists or it is something that I would have to work with some of my electronics buddies with to program.
> >
> > Anyone know of such a beast? If no one is yet selling something like this that anyone is aware of?
> >
> >
> > --- In electricboats@yahoogroups.com, Hans Kloepfer <hanskloepfer@> wrote:
> > >
> > > Hello Galstaf.
> > >
> > > I read your post about catamaran drive and maneuvering systems and thought I may put in my two cents. I work for a charter boat company called Adventure Cat in San Francisco Bay which operates sailing catamarans in the size range you are contemplating (www.adventurecat.com). On a normal day we take the boats on and off the dock at least three times in most any conditions. The boats have conventional inboards with spade rudders. I also sail my own boat, an electric auxiliary 32 foot full keel pearson vanguard sailboat.Â
> > >
> > > The interesting thing is, I can honestly say that with some basic twin screw operation skills, it is probably easier for me to dock the 65 foot cat than my own 32 foot monohull. This is because of the tremendous maneuverability afforded by twin screws so far apart. With a little practice you can pretty much walk the boat sideways if you want. You can spin around on a dime by employing contrary port and starboard thrust. If the screws are counter rotating you can pretty much ignore the effects of prop walk.
> > >
> > > If I were to build an electric cat myself (which I would love to do) I would not ever bother with the extra cost, complexity, or weight of articulating drives because you just don't seem to have that much to gain. Catamarans with hulls spread so far apart with twin screws are already spoiled for maneuverability.
> > >
> > > I can see the advantage of articulating drives on a single screw boat which does not have the luxury of the twin screws. I have seen installations with trolling motor pods mounted on transom hung rudders. I think that looks like a pretty cool and effective concept.
> > >
> > > All things considered though, if that is the system you want, and you can afford it then go for it. You are in the position to build your dream boat (something I have always wanted to do) and you should do it however you want.
> > >
> > > Good luck,
> > > Hans K.
> > >
> > >
> > >
> > >
> > >
> > > --- On Sat, 11/6/10, Galstaf <richard@> wrote:
> > >
> > > From: Galstaf <richard@>
> > > Subject: [Electric Boats] Long Range Boating with Multidirectional Docking Electric Motors
> > > To: electricboats@yahoogroups.com
> > > Date: Saturday, November 6, 2010, 5:16 PM
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Â
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Hi all... been following the group for a couple of weeks now with interest and am putting together my plans for an electric catamaran around 50 feet in length, 17 foot beam and about 25000-30000 pounds total weight. Estimated draft is about 20 inches.
> > >
> > >
> > >
> > > I am working on control systems and have heard of these "easy docking" systems that consist of an electric motor that can rotate in any direction and is guided using a joystick type "drive-by-wire" situation (no mechanical connection between steering control and the actual rotating rudder/propulsion mechanism).
> > >
> > >
> > >
> > > What I am wanting to do is use this type of system with electric wire controls for long distances (hours at a time) *instead* of having a docking system and a main drive/rudder setup.
> > >
> > > Ideally, when coming into dock, the same system can then be used to drive the boat sideways, forwards, backwards, whatever for easier docking. It could also be a great system for emergency maneuvers if ever necessary.
> > >
> > >
> > >
> > > So for those with far more experience in these matters, I have a few questions.
> > >
> > >
> > >
> > > 1. Is it possible to put together one of these systems to power the boat full time... i.e. drive the boat in a mostly forward direction for hours at at time with no ill effect?
> > >
> > > 2. Can these motors be used effectively up to around 10 knots without excessive drag on the hull? Would the propeller size/style need to be changed? (Typical target cruise speed is going to be 4-6 knots).
> > >
> > > 3. Can anyone that is actually using a system or is intimately familiar with one in actual usage make a recommendation for a brand and type of these docking motors for a craft of this sort of size?
> > >
> > >
> > >
> > > Thoughts and comments from experienced mariners is sincerely appreciated!
> > >
> > >
> > >
> > > My Best,
> > >
> > > Bill
> > >
> >
>
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