Question, My 1984 Hunter 31 does not seem to provide its full hull speed while motoring. I have plenty of rpm, just no power or speed. Im thinking my prop needs to be pitched 2". Does anyone own the same year/length with Yanmar 2GM engine, that could give me a suggestion. I need to be able to move out of the way, currently I have difficult time manuevering from dock during running tide in/out. I traveled thru the point pleasant canal this past summer against the running tide and went 2 knots, the bridge attendants asked if I was having engine trouble?, I think I should have had more power and speed. Please any suggestion would be helpful.
Prop Size
- Thread starter OceanDriver
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I was running a 2 bladed fixed prop on my 05 hunter 306 equipped with a 2GM20F. It handled horribly in tight manoeuvres around the dock and heavy winds under motor. I've purchased a three bladed maxi prop from PYI to resolve the issue. It's a lot of money, but worth the piece of mind.
A three bladed prop is the way to go. Prop walk in close quarters and reverse is increased but you get used to it and work with it.
If you have concerns about drag go with a three bladed folding or the less complicated fixed three bladed Cambell Sailor prop which is pretty good.
If you have concerns about drag go with a three bladed folding or the less complicated fixed three bladed Cambell Sailor prop which is pretty good.
You need to have a prop shop giv you an estimate of prop size for that size boat and for the 2GM20F engine. I have a 1990 H-33.5 that has a Yanmar 2GM20F engine. Hunter determined that that was under powered for a 33.5 and the following year put in the 3 Cyl 3GM27F engine. For my model year they "compensated" by putting on a 16 x 11 prop. I had adequate speed (5.5 to 6.5 Kts) but could not run it up to 3000 RPM without getting smoke out of the exhaust. I had the prop re-sized down to 15 x 11 and now can run uo to over 3000 RPM and stil have adequate speed. A good prop shop will be helpful to you in determining proper prop size.
Put a three blade prop on as suggested. On my 33 with a 2QM15 it made all the difference. Here is a good source to call for information.
http://www.discountprops.com/
http://www.discountprops.com/
Our '85 H'31 with a 2GM did well with a 15 x 10 2 blade. We had one of these (CDI Prop). http://www.sailcdi.com/ppmain.htm Boat was able to maintain hull speed 6+ kts. except in heavy chop.
Original prop was 15 x 12 (too much pitch)
Original prop was 15 x 12 (too much pitch)
Thanks so much for the info, looking forward to getting max speed in chop and against the tides.
I have same problem on my 320 so I requested some info on the Campbell. They responded with...
"Based on the information that you have provided, we would recommend a CS3RH13x7x1 for your installation. This is a Campbell Sailer, three blade, Right Hand rotation, 13" diameter, 7" pitch for a 1" SAE standard taper shaft. This size is recommended to give you a good cruising rpm and still have reserve for head wind and seas. We have completed a number of similar installations on the Yanmar 2GM20 engine with good success."
"The Campbell will provide greater thrust, improved reverse control / maneuverability and allow for a smoother running installation when compared to your existing 2 blade prop. Also, the narrow blade profile of the Campbell prop allows for reduced drag under sail, up to 35-40% less drag when compared to equivalent size props from other manufacturers."
I'm thinking about giving it a try.
Gareth
"Based on the information that you have provided, we would recommend a CS3RH13x7x1 for your installation. This is a Campbell Sailer, three blade, Right Hand rotation, 13" diameter, 7" pitch for a 1" SAE standard taper shaft. This size is recommended to give you a good cruising rpm and still have reserve for head wind and seas. We have completed a number of similar installations on the Yanmar 2GM20 engine with good success."
"The Campbell will provide greater thrust, improved reverse control / maneuverability and allow for a smoother running installation when compared to your existing 2 blade prop. Also, the narrow blade profile of the Campbell prop allows for reduced drag under sail, up to 35-40% less drag when compared to equivalent size props from other manufacturers."
I'm thinking about giving it a try.
Gareth
Just a reminder, if your prop is fouled, you'll have plenty of rpm and no thrust. Had that happen to me this year. 6 months after haulout (and had the prop treated), it fouled so bad the boat would hardly move. I thought I'd lost the transmission or something at first. Best of luck whatever you decide.
Maine Sail did a nice write up on the campbell sailor props, they are probably the best fixed blade prop made, and have the lowest drag of any fixed blade as well.
I tried searching the forum, but search says there are no posts in the last 3 years with the term campbell in them, this thread included... so you may need to contact MS if you cannot do better, sometimes I use Google to search the site, better results than the native search.
EDIT, just noticed my autocorrect changed it to cambell instead of Campbell, might have done the same when I searched
Yup, it was.... here's the write up
http://forums.sbo.sailboatowners.com/showthread.php?t=117606&highlight=campbell
I tried searching the forum, but search says there are no posts in the last 3 years with the term campbell in them, this thread included... so you may need to contact MS if you cannot do better, sometimes I use Google to search the site, better results than the native search.
EDIT, just noticed my autocorrect changed it to cambell instead of Campbell, might have done the same when I searched
Yup, it was.... here's the write up
http://forums.sbo.sailboatowners.com/showthread.php?t=117606&highlight=campbell
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