Hypothetically Speaking

[WoundUpMarine]

Hypothetically speaking, what's the thought of dropping a 42p, 240hp Volvo in my 23 seaway? Right now it has a 55hp Perkins, unknown gear ratio(definitely not 1:1 though) and a 14x10 prop and makes about 12knots. There was never a tachometer on the boat so I have no idea what the engine was turning to make that speed. I'm picking up a 1:1 ratio 72C BW gear for the project. Plan would be to use a 1.25 shaft, and a 15x? wheel, the Volvo spins up to 4200. The prop aperture is 18 inches and I'm fine with the clearances. What size wheel would I need? Boatdiesel prop calculator says a 15x15 wheel, but I'm not sure, should be easy to find one to test it out.

 

[Genius]

watching....

looks like a bronze shaft?

 

[xbskt]

How much does the Volvo weigh?

 

[WoundUpMarine]

How much does the Volvo weigh?

around a thousand pounds

 

[xbskt]

around a thousand pounds

I think it would be doable and cool but you might need more fuel aft for balance and maybe some lifting rails.

 

[WoundUpMarine]

I think it would be doable and cool but you might need more fuel aft for balance and maybe some lifting rails.

I'll shove the engine as far back as possible just to keep the weight aft. When the time comes I'd probably float test it with no fuel to see how it sits and then use a couple saddle tanks. I'd like to keep the stern open if at all possible.

 

[chortle]

Hypothetically speaking, what's the thought of dropping a 42p, 240hp Volvo in my 23 seaway? Right now it has a 55hp Perkins, unknown gear ratio(definitely not 1:1 though) and a 14x10 prop and makes about 12knots. There was never a tachometer on the boat so I have no idea what the engine was turning to make that speed. I'm picking up a 1:1 ratio 72C BW gear for the project. Plan would be to use a 1.25 shaft, and a 15x? wheel, the Volvo spins up to 4200. The prop aperture is 18 inches and I'm fine with the clearances. What size wheel would I need? Boatdiesel prop calculator says a 15x15 wheel, but I'm not sure, should be easy to find one to test it out.
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Sounds like fun but I would keep looking for a lightweight Yanmar, might be more zoom.

 

[WoundUpMarine]

Sounds like fun but I would keep looking for a lightweight Yanmar, might be more zoom.

I agree about rather having the Yanmar, but the Volvo is sitting in my shopping just waiting for something to do.

 

[[email protected]]

Ok, first, to me, it's a cool idea. Second, run what you brung. Yeah, Yanmar is OK but if there's a Volvo around use it, it's not like they're no good. The tach thing, $50 Stinger. Worth every penny and you'll use it before and after the project. Check crank and shaft speed. As for prop calculator, I gave up on it. Ran 2 boats through 4 different engineering spreadsheets and they all overwheeled the shit out of them. I would borrow any wheel i could and go from there. Shitty old Bronze can be repitched 2 inches and if you like the boat enough you can treat her to NiBral after a few seasons.
As for pushing the weight aft, I'm all for it. But I own a JC, if the weight isn't aft the boat decides where you're going, not you.

 

[[email protected]]

Also, looks like a great little boat, worth redoing. With a big diesel my son would probably finally let go of his Ken Craft to get this.
Now I'm rereading some of this. Are we like drug addicts convincing ourselves that our habits are OK?

 

[Diesel Jerry]

A definite go in my opinion. You have a long history of running boats so I have no doubt you can handle it.
I mean we see boats that are twice as long but with 4 or 5 times the hp.

 

[Quik Fix 16]

Whatcha doin wit da Perkins

 

[traditions]

Whatcha doin wit da Perkins

There was a 4 cylinder perkins with a hurth gear on FB marketplace this morning for 300$

 

[WoundUpMarine]

Whatcha doin wit da Perkins

Perkins is locked up tighter than Fort Knox. It’ll come out and then who knows. If I can free it up I’ll sell it, if I can’t I’ll part it out and scrap the leftovers.

 

[the_Bartender]

I see you have an engine waiting, @WoundUpMarine , but I thought I would throw these out there in case someone is looking. I do not have any affiliation with these engines.

Volvo Diesel engine - boat parts - by owner - marine sale

Volvo Kamd 42 230 hp purchased as spare Runs on stand Injecters turbo and exhaust elbow new With gear 2:1

norfolk.craigslist.org

1984 Perkins 4 cylinder diesel engine 4.108 - general for sale - by...

45 HP Perkins diesel with less than 500 original hours (since new!) Engine was taken off of RV generator that had electrical issues with the generator. Engine has an exhaust manifold heat exchanger...

norfolk.craigslist.org

 

[samhop]

If you can get enough wheel on it and the gear will take the power why not. you know what i think its a good idea even if you have to go new shaft, gear, wheel, drop the skeg and move the engine bed for weight.

 

[PatriciaLynn]

Rebuild one of those 305's with a stroker cam. In fact, I should have done that.