Best Servo/Motor for job?

[kevinisnekkid]

Ok, I'm waiting on my AVR chips. And I thought of a cool project to do. I am overhauling my boat. It's a 14ft fiberglass boat with a 55hp outboard motor. I would like electronic controls. Doing a speed control should be easy enough, the cable for the carb is easy to move. How would I go about figuring out what it takes to turn the outboard motor? I haven't had this engine running yet so I don't know how hard it will be to turn.

For starters, I just want electronic controls. Later, I want to be able to program in a course, and have the boat take me there.

[ArcMan]

I would go with a DC gearmotor turning an acme lead screw.  The acme nut would be attached to a bracket on the motor out a ways from the outboard motor pivot.  Attach a multi-turn pot or resolver to the lead screw shaft for position feedback.  You'll need a pretty beefy gearmotor for this.

[kevinisnekkid]

I see the direction you're heading. But I have a few concerns.

First, the steering mount travels in an arc, not a straight line. The mount is about 10 inches from the pivot point.
Second, it seems like it would be hard to have a manual override with that design.
Third, I'm not sure how it would work with tipping the motor up while the boat is being towed.

I took a further look at what was left of the old steering system. Attached to the steering wheel was a small gear that turned the big gear that pulled on a cable. The big gear probably makes only a half a turn. It has 2 placed where the cable comes out. If I had the cable & other parts, I would connect a geared motor to the steering wheel. Alas, that is not the case. But perhaps I can use the same concept.

-Kevin