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For simplicity I was thinking about putting two yamaha's on both sides of stern ramp to get max manueverability and right hight to water for outboards has anyone else tried/seen this work?

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Seems very high from the water to me: you may have to build strong brackets to have them right, then they will be low and get exposed to the seas, unless you have a lifting bracket (what a pain...). You will also lose the fact that when mounted forward, the propellers do not cavitate when hobie-horsing: they are close to the center of gravity. Maneuverability is also better when center mounted.

You will have to reach the rear beam to lift/lower/manipulate the engines which can be difficult and dangerous. A 9 hp Yamaha is 100 lbs...

With the boxes mount, engines are hidden and when boxes and engines are up, lids are closed, you forget about them and not worry about the drag, they have completely disappeared. All operations on them are done safely at deck level and between the hulls.

In other words: I like very much the engine boxes mount on my Tiki38.
Jacques said:
Seems very high from the water to me: you may have to build strong brackets to have them right, then they will be low and get exposed to the seas, unless you have a lifting bracket (what a pain...). You will also lose the fact that when mounted forward, the propellers do not cavitate when hobie-horsing: they are close to the center of gravity. Maneuverability is also better when center mounted.

You will have to reach the rear beam to lift/lower/manipulate the engines which can be difficult and dangerous. A 9 hp Yamaha is 100 lbs...

With the boxes mount, engines are hidden and when boxes and engines are up, lids are closed, you forget about them and not worry about the drag, they have completely disappeared. All operations on them are done safely at deck level and between the hulls.

In other words: I like very much the engine boxes mount on my Tiki38.

I was thinking about lowering the ramp to get the outboards to the water. How do the boxs work amidship do they have a lowering bracket?
If the attachment points of the motor brackets to the catamaran are in the back, the motors should be turnable - at least 25° on either side. In this case there will be good maneuverability in slow motion too(can be done also with one motor - like on a dinghy)
if you mount those motors aft,and you are motoring in any kind of a seaway,those engines will be out of the water cavitating most of the time.
Don, look on my pictures, there are some of my engine boxes.
We have a Tiki 46. Our motor sticks back a few inches farther than the plans call for. We get some slight "cavitation" as the bows dip down. I would not move them any farther back. In fact if I were to do it again I would consider moving them amidship to help keep them in the water. And I would put more of a "keel" or sharper wedge on them to help them break the waves.
My 5hp Nissan long-shaft is fantastic for steering the boat with in tight quarters:


I do have to watch it if I am in a bumpy sea, but I really prefer to only use it when inside the harbor.
I can really pivot the boat nicely by pointing the screw in the direction I want to go when I have no way on. Two screws is another matter, of course.

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