cioto wrote:
I managed to modify the joint, and found a way to install on the right side.
But before drilling holes in my kayak, I want to ask you: is it right that the motor is more efficient at the stern, compared to a mounting in the mirage drive cassette?
The cassette mounting would be a lighter installation... but I would lose the ability to use pedals and motor together... and I think the motor is less efficient in that position...
Excellent observation, many people fail to consider this. I've brought this up before but I'm not sure if anyone took note of it.
A motor is usually most efficient where you see it mounted on the vast majority of boats, in the exact center of the boat at the back of the stern. It was mounted there by boat designers for very good reasons. Other positions can still work well but may be somewhat less efficient.
For example, mounting a motor to the left or right of center will create a lateral acting torque that will tend to steer the boat in the opposite direction. The further from the center, the greater the torque. This force must be offset by the rudder and the hull, resulting in an efficiency loss of the desired directional force, i.e. forward thrust. In a powerful motor, this loss may be relatively insignificant, but in a very small motor with only 1-3 HP, it may be significant. This is why I prefer to mount the 403 Ultralight in the center. I tried to procure an 1103AC Ultralight last season but was not successful. I plan to contact Torqeedo again as soon as I return from vacation. If I'm successful, I'll try to engineer a rear center mount solution for the 3HP 1103AC on the TI as well.
Additionally, anything that might interfere with the ideal prop wash might also cause a loss of power. So if you mount a motor underneath or to the left or right of the boat near the hull and the resultant prop wash is disturbed and/or deflected by the hull, a loss of forward thrust might occur. Again, the loss might be small, but we're dealing with very small motors, so it should be considered. With a jet boat, the prop wash is purposely deflected to make the boat slow down and even reverse, so you can easily imagine the deleterious effects of anything that might deflect an ideal prop wash.
In the absence of an ideal installation, this potential and unavoidable loss must, unfortunately, be accepted. Any loss in efficiency is undesirable but no motor configuration is 100% efficient.