Wondering if anyone has a boat out for winter or knows what the centerline of the shaft to hull clearance is on a 78 era vintage hunter? I am repowering my boat and considering options for a new prop. My boat is currently in the water and as such is hard to measure. any help would be greatly appreciated! R. Paquin
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Colin
You could try this.
Find out from Hunter what lengths they used and buy one too long. You could then cut it to length when you get the old one out. One end is almost certainly plain.
Find out from Hunter what lengths they used and buy one too long. You could then cut it to length when you get the old one out. One end is almost certainly plain.
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Ed Schenck
Why change?
Not sure I understand. Why would the diameter of the prop change with a repower? The strut and shaft relation to the rudder should remain unchanged. If you use the recommended prop size then clearance is not an issue. Are you thinking that you want more diameter because of more horsepower? In that case you are right, you need to know that clearance. I would opt for pitch and not diameter so as not to worry about it.
Not sure I understand. Why would the diameter of the prop change with a repower? The strut and shaft relation to the rudder should remain unchanged. If you use the recommended prop size then clearance is not an issue. Are you thinking that you want more diameter because of more horsepower? In that case you are right, you need to know that clearance. I would opt for pitch and not diameter so as not to worry about it.
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Brian
I agree with Ed
I agree with Ed, you shouldn't have to worry about the clearance if you are keeping the same size prop. I have to confess that I am not entirely sure I have all the info on what you are trying to do. But I have some knowledge and understanding of what is involved with changing engines. If the dimensions of the new engine fit in your existing space, there is clearance for engine service, and the motor mounts will line up close enough for proper alignment, then the next thing to compare is the distance from the rear motor mounts to the coupling on your transmission. This will tell you if you need a longer/shorter drive shaft. You may be able to find the length of what you have in the boat specifications part of this website. I hope this helps.
I agree with Ed, you shouldn't have to worry about the clearance if you are keeping the same size prop. I have to confess that I am not entirely sure I have all the info on what you are trying to do. But I have some knowledge and understanding of what is involved with changing engines. If the dimensions of the new engine fit in your existing space, there is clearance for engine service, and the motor mounts will line up close enough for proper alignment, then the next thing to compare is the distance from the rear motor mounts to the coupling on your transmission. This will tell you if you need a longer/shorter drive shaft. You may be able to find the length of what you have in the boat specifications part of this website. I hope this helps.
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R. Paquin
prop shop is recommending 16x9
the prop shop is recommending going to a 16x9x3 to get the best out the new horsepower, I'm repowering from a YSB-8 to a new yanmar 2gm20. they gave me a formula of 15 percent of new prop size plus half diameter of new prop plus three inches for clearance from the hull. So for a 16x9 prop I would need a total of 13.4 inches of clearance from the prop centerline to hull. thanks!
the prop shop is recommending going to a 16x9x3 to get the best out the new horsepower, I'm repowering from a YSB-8 to a new yanmar 2gm20. they gave me a formula of 15 percent of new prop size plus half diameter of new prop plus three inches for clearance from the hull. So for a 16x9 prop I would need a total of 13.4 inches of clearance from the prop centerline to hull. thanks!
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Ed Schenck
Guessing here, but. . .
I cannot visualize that much clearance on an H27. If I can remember I might measure one for you tomorrow when I am at the marina. My H37C has an honest 20HP and uses a 15" prop.
I cannot visualize that much clearance on an H27. If I can remember I might measure one for you tomorrow when I am at the marina. My H37C has an honest 20HP and uses a 15" prop.
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R. Paquin
that would be great!
I'm thinking a 14" will have to do... I had no idea I was gonna have to change so much stuff when repowering.. it keeps adding up.. new controls & cables, new vlift, new return lines to the diesel tank, new exhaust lines and thru hulls etc
I'm thinking a 14" will have to do... I had no idea I was gonna have to change so much stuff when repowering.. it keeps adding up.. new controls & cables, new vlift, new return lines to the diesel tank, new exhaust lines and thru hulls etc
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David Foster
Careful!
The prop on our '77 h27 is 12 inches. The specs on this site say 13. We have moved 2 1/2 hours south of Lady Lillie, so I can't go out and measure for you. But I took our prop off to be reworked and add winglets at Bay Prop in Alameda, CA two months ago, and there is not way a 16 would go in there with the minimum 20% clearance. Why not tell the prop shop 13 is the old spec, and see if they can do the job in side that diameter? If not, I'd propably find a diver to go down and measure it for me. Or buy a wet suit and snorkel down myself. It's not something I'd want to get wrong! David Lady Lillie
The prop on our '77 h27 is 12 inches. The specs on this site say 13. We have moved 2 1/2 hours south of Lady Lillie, so I can't go out and measure for you. But I took our prop off to be reworked and add winglets at Bay Prop in Alameda, CA two months ago, and there is not way a 16 would go in there with the minimum 20% clearance. Why not tell the prop shop 13 is the old spec, and see if they can do the job in side that diameter? If not, I'd propably find a diver to go down and measure it for me. Or buy a wet suit and snorkel down myself. It's not something I'd want to get wrong! David Lady Lillie
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