hi all,
I'm a newbie to this, but just a thought ..
if you went to five cogs, with 1 - 2 - 4 - 5 in a row, but with 2 & 4 not touching, then fitted cog three to the motor, and positioned it above this row, and meshing with 2 & 4, you would get the two props, on cogs 1 & 5 counter rotating, and still be able to keep the motor on the centre line of the boat.
depending on how you lined up your shafts the motor could also be below the line of cogs, or in line with them.
on the plan for the psv I'm building, it shows the propshafts as parallel to the bottom of the hull, so getting the motor low enough to be in line may be a problem. the real engines obviously drive from the crankshaft at the bottom of the engine.
I assume cog 3 could be a different size to either slow down or speed up the props compared to the motor.
does this sound right, or have I made a mistake somewhere ?
having a great time reading all the posts, and learning loads !!
cheers
alan