Combo railing and swim step mount for dinghy motor on TC 255

[thataway]

I had mentioned that I was making a mount for the dinghy outboard (3.5 hp Mercury [Nissan]) for the Tom Cat 255. The goal was to put the motor on the inside of the cockpit (or outside of the transom--anyplace which fits what we are doing) and be able to use the dinghy motor for very slow trolling or pushing the boat in 15" to 17" of water, during extreme winter low tides which occur over the sandbar into the bayou behind our home.

We used 3/4" Starboard (from an old Swim Step) for the basic mount. The upper part was backed with another 3/4" to give a 1 1/2" support for the motor clamps to attatch to. The mount was made longer than the engine bracket, so that we could clear it with the 1/2" diameter, 1 1/2" U bolt we used for attatchment to the railing. The two U bolts are easily removed if we want to put the bracket on the swim step ladder mount. The photos in "Thataway" gallery show the mount still in developement--and the 1/2" bolts will be cut shorter--but length is pending if we need to add another layer of Starboard, or brace the entire bracket with metal plate (probably a 5000 series Aluminum).

The mount for the Armstrong swim ladder, which is part of the "diving" option package (highly advised for all of the Tom Cat 255's), consists of 2" SS carrage bolts which fit into a slot on the back of the Armstrong bracket. The bolt head is too large to slide in the "U" of the ladder support bracket, so it has to be ground down on the sides and on the very bottom. The 1/2" nuts are brought up hard against the shoulder of the square 1/2" of the carrage bolt. A washer will not fit here, but the nut gives adequate bearing surface. The starboard is sandwiched between two washers and nuts, which are snugged tight. There are other 3/4" starboard pieces used to "bury" these nuts, when the U bolts clamp this to the railing. The engine will have a slight "up" thrust, but the prop should be well below water. The lack of effeciency is not of major concern, since we don't expect the engine to push the boat more than a knot or two.
I have used this same engine to push a 9,000 lb boat drawing 22" (outdrive up) over this same sand bar a number of times and is plenty of power. It will also be ideal for very slow trolling--such as Salmon--where we want to go 1/2 to 1.5 knots.

Any comments are appreciated!