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[yoric]

as a new guy to all this i have a few question ... actually i have more questions than i have answers buy we'll take it slowly for now.

the project is a twin motor MTB boat from the '40's vintage which someone else is building a hull. my plan is to install a pair of props and run them off 2 separate motors and all will be hunky dory so here are the questions:

1) which way are the props supposed to rotate? I know hey are supposed to counter-rotate but does it matter which direction (towards the centre or away?)
2) angle of prop shaft? The plans call for a 10 degree angle from the bottom of the boat (actually they quote 169.98 but thats from the wrong direction and i don't think i can get it accurate to 0.02 degrees) but how much play is there in this angle and still allow a good planing?

and now we come to the killer ...

3) has anyone set up a twin motor system using IC motors? i know the difficulties in tuning 2 carbs to give the same output but luckily i have an expert on hand that is going to do it for me, at least out of the water. i also know there are going to be some fun and games when it comes round to mounting the motors as 1 has to be geared to rotate the shaft in the opposite direction and i have a plan in mind to do just that but i just wanted a little input from you experts on how you did it.

thanks in advance

p.s. i couldn't find the right forum for this so can the mods please move it to where its supposed to be.

Ta

Karl

[triumphjon]

silly question , rather than two ic engines would it not be easier to install one engine driving the twin shafts thrrough a gearbox ?

[longshanks]

When looking from the stern it is usual for left prop to turn anticlockwise. The right to turn clockwise.

Sillier question......why not install electric motors and have full control ?  OK2

[DickyD]

I'm assuming you have somewhere to sail an i/c boat ?

[yoric]

silly question , rather than two ic engines would it not be easier to install one engine driving the twin shafts thrrough a gearbox ?

i did look at the gearbox route (even designed my own with the aid of a catalog from someone who makes gears) but to make the gearbox strong enough against the water pressure of twin screws it would have to somewhat overdesigned bearing in mind all the other variables, plus with 2 motors i can retard one in conjunction with the steering controls to make for tighter turns

When looking from the stern it is usual for left prop to turn anticlockwise. The right to turn clockwise.

Sillier question......why not install electric motors and have full control ?  OK2

i wanted to get more than 10 minutes running time before i waded in to retrieve and replace batteries

I'm assuming you have somewhere to sail an i/c boat ?

i do