My boat is terribly slow under power and I suspect the propeller. I have not yet determined the size of the three blade prop put on by a previous owner. I was querying a prop dealer and he wanted to know the RPM that my Yanmar YSB8 diesel is rated at. I cannot find an answer. Does anyone know the rating on a YSB8? Has anyone researched propellers for a 1978 Hunter 27?
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target hp to weight ratio...
Ryberg: The target HP to weight ratio is about 500 lbs/1 HP. If you are over 4,000 there is not much that can be done. A three blade prop helps when the water is rough but slows you down when you are sailing. Unless you prop is just not sized for your boat, I don't think that there is much that can be done.
Ryberg: The target HP to weight ratio is about 500 lbs/1 HP. If you are over 4,000 there is not much that can be done. A three blade prop helps when the water is rough but slows you down when you are sailing. Unless you prop is just not sized for your boat, I don't think that there is much that can be done.
H27 Power
The H27 came with a one cylinder 8HP Yanmar for most of the production run. In 1980 or '81 they used a Renault engine (and this was reported to have many problems). I also think in 1984 they may have upgraded to a Yanmar 10 HP. The factory prop was a two-blade fixed prop. I owned a 1979 H27 for 15 years. Great boat, but woefully underpowered. As reported by someone else, the best you can do is 4.5 to 5 knots. Changing props won't help. Make sure the bottom is as clean as possible. Also, motor sail whenever possible.
The H27 came with a one cylinder 8HP Yanmar for most of the production run. In 1980 or '81 they used a Renault engine (and this was reported to have many problems). I also think in 1984 they may have upgraded to a Yanmar 10 HP. The factory prop was a two-blade fixed prop. I owned a 1979 H27 for 15 years. Great boat, but woefully underpowered. As reported by someone else, the best you can do is 4.5 to 5 knots. Changing props won't help. Make sure the bottom is as clean as possible. Also, motor sail whenever possible.
Sheet did not attach
The photo attach did not work, but it was ahuge file ~6 MB. I assume the YSM and YSB ratings are the same.
The photo attach did not work, but it was ahuge file ~6 MB. I assume the YSM and YSB ratings are the same.
Prop RPM is key
Thanks to all for the info. I think I have now seen that spec, too. My next question is how to determine which transmission I have. If it is the 3.1:1 then my prop is turning much slower than expected.
Thanks to all for the info. I think I have now seen that spec, too. My next question is how to determine which transmission I have. If it is the 3.1:1 then my prop is turning much slower than expected.
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