No wonder it went like stink, what size of prop’ did it have?
The whole thing was cobbled up outta stuff that was laying about, it was a bit of a floating junk yard.
I don’t recall the details of 30 odd years ago but the gearbox was a Coventry out of an ancient lifeboat it was an island type design, meaning it was mounted separately from the engine.
Originally as fitted to the lifeboat it was powered by a bloody great crank handle running the length of the boat with all the survivors winding it by hand! Thing thing that got me was why they thought they needed a gearbox with forward neutral and reverse….. if you needed to idle, just stop turning the crank and to go backwards just wind the other way. The whole concept was totally mad!
This allowed me to place the weight of the engine a bit further forward to held keep the bow down under full power. Which it needed as that arse would dig in deep, under full power and made a huge bow wave and a seriously churned wake.
Mind you it never had any cavitation problems.
The cooling was seawater pushed though the system by a Jabsco impeller pump, the rubber engine mounts were 4 Holden gear box mounts, these things were as common as arseholes ( everyone had one ) they were normally used in suspension with one holding the weight of the back half of the engine and gearbox.
I flipped them over and used them in compression, and with 4 of ‘em, more than strong enough for the jod.
The fuel tank came from an old Fiat 850 Sport. A bit small but adequate for what I used it for.
The prop was @ 2’ at a guess it had a fair amount of pitch, I got that from an old bloke who had the ability just look at a boat / engine combination and guess the optimal size and pitch of the “fan” required….. at no time did this bloke resort to fancy mathematical equations….he probably had trouble counting to 20 without tacking his shoes and socks off and would then need to take his pants off to get to 21!