I have been pricing used motors for a while now. It seems that on occasion, bow mount motors can be had a fair amount cheaper. Being a motor novice, can a bow-mount motor be transom mounted, given a fair amount of creativity, or will it have negative effects?
The motor, shaft and most of the power head components are the same from a bow to transom mounted unit. I don't understand the difference in price, but would think the bow mount to be more expensive to produce.
In any case, the parts to change one from bow to transom mount should be available from the manufacture, if it's not too old. It would be costly to do it this way and I'd be inclined to try to modify it myself to work as a transom mount. Once fixed at the correct depth, the adjustable feature isn't necessary, so the only items left on the transom bracket to figure out are 360 degree rotation (I you want that, they do have reverse) and a tilt up feature. The hard part will be the controls on the bow mount, typically are different (foot operated) then the transom mount.
With some backyard engineering, it could be worked out. I have a butchered up trolling motor pushing my 23' sailboat about, as I dock or worm my way through, closely moored boats. The power head was removed, the wires extended and this whole assembly mounted under the tiller (still attached, but under it) The wires go to a bulkhead connector (the removable kind) so I can plug the motor to the power head and have the power leads go to the battery. The motor is mounted (on it's shaft) to the rudderhead on an aluminum bracket. This bracket is little more than a couple of 1/8" plates that sandwich the rudderhead (screwed to it) and have a couple of holes drilled through them. These holes align with an "up" position and a "down" position (matching hole in the motor shaft) and a captive ball type, quick release pin keeps the whole works together.
The process goes like this: I place the motor shaft in the bracket and insert the pivot pin (also quick release) and then insert the position pin in the up location. This attaches the motor to the boat's rudder. After I launch at the ramp, I plug in the bulkhead connector and make sure the battery is hooked up. She's ready for use. I have a lanyard attached to the motor and shaft so I can raise and lower the motor easily. In the lowered position the motor, being attached to the rudderhead steers the boat with the helm, making for very crisp handling with instant response. The rudder blade can't get hit by the prop, because it's behind the rudder and attached.
The best thing about this arrangement is the two tillers (power head controls and boat tiller) are within fingertip reach, no fumbling about, half twisted around with a trolling tiller in one hand and steering the boat with the other. It can be raised, clear of the water or removed quickly, by pulling a couple of pins and the bulkhead connector. I usually leave it attached to the rudder in the up position, but will remove it when I'm trailering. On a wheel steering, like most Weekender's, I'd still remove and relocated the power head, but I'd stick it in a cockpit locker or have the tiller part of the power head sticking out in a convenient spot. Having the motor steer with the helm is a joy.
That sounds similar to what I'd like to do for a rudder. My plan is to lay up a fiberglass rudder blade that has a pod formed into it's trailing edge for the trolling motor - no shaft. All movement will be in sync with the tiller. Same idea for routing the wires as well (b/h connector). Mount the speed control in the cockpit and you're good to go. Glad to hear the idea works well !
Brain, that was done on a boat in Wooden Boat Magazine, I have posted the link here a few times. It showed you how to set it up, run the wiring up the center of the tiller,etc.... The article was titled "A Motorized Rudder for Mia"....... you can probably find it in their archives.
Brian,
Here is how Sam Devlin does it on his "Nancy's China DC"
![[Image: nancyschinadc.gif]](http://www.devlinboat.com/nancyschinadc.gif)
- Steve
Fixing the motor in the down location is fine on boats that can't plane off. My sailer does plane and I couldn't live with that amount of drag, though the prop will free spool to a degree, still a lot of drag, right in a place it's very undesirable. The speed lose on a boat limited to displacement speeds may be negligible enough to warrant fixing the motor to the rudder.
http://www.messing-about.com/forum/download.php?id=3360