I did some research and understand that the cavitation plate has to be just below the water. Now with the adjustable height bracket, why does it make a difference to buy a short or long shaft if you can mount the bracket at an appropiate height to achieve the depth in the water? Or am i missing something stupid and obvious here... haha
- Access - being able to pull the starter cord. The motor bracket can usually be raised, so perhaps you can start motor with it up and then push it down? Hopefully still get at controls?
- Mounting the bracket low so it does not interfere with rudder when both are turned toward each other could be a challenge depending on transom geometry. I have seen too many rudders with prop gouges!
- Prop needs to be in clear flow of water from under boat.
- Prop needs to be submerged more than on a power boat so it will stay submerged in waves.
You can/could get motors designed for sailboats that have the exhaust outlet higher than standard. The engine can be mounted deeper without excess back pressure on the exhaust. On those motors, the normal exhaust outlet behind the prop is blocked off so when going astern gases are not sucked into the prop. Regular motors don't work well in reverse. Prop pitch is normally lower on these motors.
Have a walk around a few marinas and have a look at boats with similar transom height. Might give you some ideas of just what will work. I found the picture below. That boat has a 9.9HP Yamaha, but doesn't say if it is a long shaft/ This looks like same boat: 26 foot Mirage Sailboat East Regina, Regina
. Looks like the bracket gets the motor far enough back so it doesn't interfere with the rudder.
One of thos electric outboards might be better, but kind of expensive for one big enough.