When I designed my boat I thought I could place an outboard in the stern of the boat mounted as a "saildrive". Well into the building project
I learned that the propeller
would not work in that position. ROGUE's 1' draft
and the pointy underwater shape at stern would not keep the prop covered with water. It would suck air at the least provocation as a similar design did. I also decided that ROGUE had enough wetted surface in the form of leeboards and I don't want to drag a propeller
through the water. I've spent more than ten years trying to decide on a permanent solution for auxiliary power. I have considered a Yulo (Chinese sculling or of unusual efficiency), water pump as a jet drive, hydraulic motor and folding prop mounted on my rudder
(elegant but expensive and inefficient even if I could find someone to design and build the thing), various ways of mounting a four stroke, and electric outboards. I'd be a lot wealthier if I had been paid for all the time I have spent investigating these various options. I've been using a dinghy
with outboard as a tug and that may well turn out to be my best permanent option if I create a more elegant solution than the one I have been using. I have some ideas about that.
Until the Torqeedo, there were no adequate electric drive options. Because of electric storage
problems electric propulsion
must be very efficient. Inboard mountings are unlikely to meet this criteria because of bearing losses and the likelihood of inefficient propeller compromises, and that assumes not having to gear
the motor down to prop speeds. (Using an electric motor
in place of a transmission
so as to be able to move the weight and accessibility of the engine
to another location may be viable; trading mechanical transmission
inefficiencies for electric inefficiencies. When fuel
cells become reliable, and long lasting in the marine environment
, electric drives will be the way to go.)
Torqeedo outboards are elegant and efficient designs, far superior to anything else on the market (I've been looking for years and considering various options.) The lighter weight and small visual impact of the Torqeedo may make mounting it on ROGUE's tiller practical, though it would still affect the steering
when heeled. ROGUE is so well balanced I can leave the tiller to go do other things while sailing to windward. The convenience of flicking a switch to motor back to port when the wind dies may be worth it to avoid the inflate the dinghy
, launch and secure it as ROGUE's tug, mount the outboard and gas tank, start the engine scenario.
There are other mounting options as well, all of which are more elegant with the Torqeedo than a four stroke mounted the same way. Solar
cells and a nice quiet honda
generator could be used to top off the battery and extend range for the few times I would want to motor any distance.
The biggest question is, what size Torqeedo would provide adequate propulsion
for my boat??? Or yours Ericsn25Chespk
I have not been able to find any reliable information about what the actual usable thrust of various gas outboards would be on my boat. A six HP two stroke has been adequate. However, matching outboard horse power figures with electric horse power figures provides no comparable information about performance in the real world. Even thrust figures are not relevant because they are measured in various ways, and what is relevant is the ability to move a displacement hull
along at less than 6 mph, so even real measures of static thrust is not terribly relevant except when it is not enough thrust to exceed the efficient speed of my hull
. Even Torqeedo's technical information stating in the same chart, propulsive equivalents and thrust equivalents to gas outboard HP and the horse power are different from two terms I would interpret as synonyms, but they quite apparently are not, so I have no ideal what it all means in terms of my needs. (My boat is a sailboat. Auxiliary propulsion is for bridges, canals, and when there isn't any wind.)
If anyone has any information about real world performance of Torqeedo outboards in comparison with the gas outboard that had been propelling a particular sailboat, I sure would like to hear it. I talked to a dealer who used (I believe) an 801 mounted on a 19' full keel
sailboat along the coast of Maine
. It handled waves and current "like a six hp gas outboard". That motor was a beautiful design. LONG shaft. Can be tilted up. Can also slide up the length of the shaft.