Inboard engine idea

[Dieselboatman]

One thing that I´m guessing needs to be looked in to is that a gearbox from a car isn´t made for the force that the propeller causes to the outgoing shaft of the gear box

That's why I realise a thrust bearing would be required to stop it smashing the car gearbox apart

As for the book, will have a look
That's a different approach to the issue, I do like that idea actually!

A lot of newer gearboxes have reverse directly opposite 5th, so actually could leave gearbox intact, and simply have a selector rod on a sort of Z gate
So 3rd, then back and right and back further for reverse

Would actually prefer having a separate throttle and gear lever anyway (would choose that over the common single lever throttle and gear setup)

And with not modifying the gearbox it would be stronger than the chain setup
Clutch would need connecting obviously, if kept
But that could simply be a hydraulic setup using a motorcycle clutch or brake master cylinder
On the actual gear lever

 

[dava]

That's why I realise a thrust bearing would be required to stop it smashing the car gearbox apart

As for the book, will have a look
That's a different approach to the issue, I do like that idea actually!

A lot of newer gearboxes have reverse directly opposite 5th, so actually could leave gearbox intact, and simply have a selector rod on a sort of Z gate
So 3rd, then back and right and back further for reverse

Would actually prefer having a separate throttle and gear lever anyway (would choose that over the common single lever throttle and gear setup)

And with not modifying the gearbox it would be stronger than the chain setup
Clutch would need connecting obviously, if kept
But that could simply be a hydraulic setup using a motorcycle clutch or brake master cylinder
On the actual gear lever

The book is great, my dad even made gearboxes in a frame with thrust bearings in front and behind so they could be totally independent of the engine and simply connected with a prop shaft, we used to use land rover ones.
I had a 38' pinnace once that we converted to twin-screw, since she only had 9' beam he set both engines up in line in the centre with 1 back to front and improvised a vee drive from another box, both 127hp ford cargos, she absolutely flew, was a bit of a handful with 2 gear levers, clutch pedals and throttles like but really the possibilities are endless as long as you have determination and a decent mechanical brain. Good luck.