Does anyone happen to know the measurement between the prop shaft and the hull on a 1979 Hunter 30? I'm in the process of trying to determine the best prop size to put on my boat, and this is one of the pieces of information I'm missing. You'd save me having to dive over the side in a dirty canal to measure it... ;-) Regards, David.
Propeller clearance on 1979 H30
- Thread starter David Hoy
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Prop size
I sympathize. We have a 1976 Hunter 30 with a new 25 HP Vetus diesel. I Have been working on prop sizing for weeks, and I can't get the same answer from any two people. I know the distance between the tip of the prop and the underside of the hull has to be at least 15% of the diameter of the prop. Everything else is pls or minus (+/-) a hammer handle. I have heard everything from a two blade 13" 9 pitch to a three blade 14" 10 pitch based upon my motor size. Look for a place that has prop scan software, thats a little better than an guess. They need displacement, length at waterline, gear ratio, Horse power, RPM's at wide open throttle, and they can come pretty close. Sorry I couldnt help more
I sympathize. We have a 1976 Hunter 30 with a new 25 HP Vetus diesel. I Have been working on prop sizing for weeks, and I can't get the same answer from any two people. I know the distance between the tip of the prop and the underside of the hull has to be at least 15% of the diameter of the prop. Everything else is pls or minus (+/-) a hammer handle. I have heard everything from a two blade 13" 9 pitch to a three blade 14" 10 pitch based upon my motor size. Look for a place that has prop scan software, thats a little better than an guess. They need displacement, length at waterline, gear ratio, Horse power, RPM's at wide open throttle, and they can come pretty close. Sorry I couldnt help more
not sure your barking up the right tree.
You should give general propeller in bradenton florida a call. they can size a prop for that boat over the phone. they are very good folks and know exactly what the conciderations should be.
You should give general propeller in bradenton florida a call. they can size a prop for that boat over the phone. they are very good folks and know exactly what the conciderations should be.
Prop Size - David
I have such a program. If you would like to send me have the info listed in Bob's message I can let you know the result. Also required is the desired diameter. Usually the largest you can fit BUT leaving 15% diameter clearance to hull. This is to reduce prop walk and turbulence noise transmitted thru hull. Suggest we correspond outside of HOW so my e-mail is donalex@compuserve.com. It might just add to the confusion!!!
I have such a program. If you would like to send me have the info listed in Bob's message I can let you know the result. Also required is the desired diameter. Usually the largest you can fit BUT leaving 15% diameter clearance to hull. This is to reduce prop walk and turbulence noise transmitted thru hull. Suggest we correspond outside of HOW so my e-mail is donalex@compuserve.com. It might just add to the confusion!!!
Some dimensions
On my previous boat, a 1980 Hunter 30, the "aperture" or space between the prop strut and the skeg for the rudder was 12" long overall and 8" from the center of shaft to bottom of hull. I had a somewhat longer (51") shaft and there was 6" of clearance from the prop nut to the leading edge of the skeg. I had the Yanmar 2QM15 engine. The original prop (13 X 13) had a 6.5" radius, leaving only 1.5 - 2 inches from the tip of the prop to the hull. This represents only 11.5% - 15% of the prop diameter. Ideally there should be a space of at least 2.5 inches, or 18-20% of the prop diameter. Hope this is of some help.
On my previous boat, a 1980 Hunter 30, the "aperture" or space between the prop strut and the skeg for the rudder was 12" long overall and 8" from the center of shaft to bottom of hull. I had a somewhat longer (51") shaft and there was 6" of clearance from the prop nut to the leading edge of the skeg. I had the Yanmar 2QM15 engine. The original prop (13 X 13) had a 6.5" radius, leaving only 1.5 - 2 inches from the tip of the prop to the hull. This represents only 11.5% - 15% of the prop diameter. Ideally there should be a space of at least 2.5 inches, or 18-20% of the prop diameter. Hope this is of some help.
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