S2 11.0 Prop

[Spike033]

Last year I was considering getting a new prop and sticker shock (thought they would be around $400 at most) quickly detered me when I was told they would be more like $4000. I read an article in one of my magazines about the different types of Folding Props available. I would like to get a 3 blade folding type. I am not sure which one yet, but before I start pricing I would like to know what size, rotation direction and pitch I have. I looked at my prop before I put it in the water this year and there was an S2 stamp on it. It is a 2 blade. I am thinking it may be the original prop? Are there standard prop configurations that S2 used that would make this a definite answer or are there a whole bunch of variables I am missing?

I have a Volvo Penta MD17C Engine on a 1980 11.0A. I certainly would like to hear what is or isnt working for you. The reason for the change is I would like more control coming in and going out. I am not a racer so I dont need the .0001 knot difference with drag. I just want something that will reduce the drag better than the basic 2 blade and give me more control. The folding types seem to be the answer.

 

[Jtoben]

Do you have the sail drive?

 

[Spike033]

No it is not a saildrive. I have been asing around and nobody really has a definite answer. I get all sorts of answers, most contradict each other. My guess is that I will just deal with what I have and get used to it.

 

[BobM]

control issue

Perhaps control is the key issue rather than the propeller. Is there a specific problem you are having? I don't think that a different propeller is going to solve many control issues. Is the issue prop walk or are you having difficulty due to tides / winds preventing you from reaching hull speed?

Have you looked at the Campbell Sailor? Their fixed three blade props have about the same drag as a two blade stock prop.

http://www.westbynorth.com/CampbellSailer.aspx

 

[RussB]

I changed the stock two blade Michigan sailor prop on my 9.2A (yanmar 2qm15) with a Campbell sailor three blade fixed and it's like night and day. I am motoring at about 6.2 knots in calm conditions vs 5.5 knots with a lot less vibration. The prop is slightly strong for the engine and I get alot of soot in the exhaust if I over throttle. I could look up the diameter and pitch but I don't think that would be meaningful for an 11.

Russ

 

[RussB]

I just checked and my Campbell Sailor is an R14x8x1 (righthand rotation, 14 inch diameter, 8 inch pitch for 1 inch shaft. It cost about $550 in 2008.

Russ

 

[BobM]

Performance

I just checked and my Campbell Sailor is an R14x8x1 (righthand rotation, 14 inch diameter, 8 inch pitch for 1 inch shaft. It cost about $550 in 2008.

Russ

Hey Russ,

I was wondering about what RPM is it maxing out at with the new prop? This sounds like a great option for me, but I want to get the right size if I go this route. The proper sized prop should still max out at 3200 RPM. I bought a folding two blade, but it likely has too much pitch. It is a 12 pitch and my original is a 10. It would be nice to do hull speed under power. I max out at 5.5 now.

Thanks,

Bob

 

[RussB]

Bob,

I don't have a tach but would guess that the exhaust is showing black smoke at about 80%. At 100% it is smoking excessively. If I was getting the prop today I would get it with about 7.5 pitch. Although the issue with low throttle with diesels is overheating. My little 2QM15 has never acted overheated at 70-75% throttle. I am very happy with the prop.

Russ

 

[Spike033]

Thanks for the discussion. The "R14x8x1 (righthand rotation, 14 inch diameter, 8 inch pitch for 1 inch shaft. It cost about $550 in 2008." and the following comments helped me understand more. I just motored for 3 hours at 2600 RPM at 5.4 Knots (according to my ST60+)My Cell phone GPS app had me 7 knots. Control is the issue (My lack of control). When docking I enter the slip at about 2knots and as I close in to the dock if I off slightly the wind pushes back and I cant generate power fast enough to get the boat in reverse to correct. I know that there needs to be movement accross the Rudder to make the boat move. I just want more thrust on demand at a lower RPM. I have gotten better, but I am looking for the short burst power. I just figured if I was looking at a new prop, I would just get a folding prop. I just dont know the Rotation/Blade Diameter/Pitch/shaft diameter equation for the 11.0A. I was just looking for those numbers if anyone had an 11.0. That way I could compare all the options on the blade I would want. NOW, I am wondering if maybe just deal with what I have and put in a BOW THRUSTER (only kidding about the BT)... although it would help. Thanks again for the discussion

 

[BobM]

There is free program I have used in excel called propcalc or something like that. If you do decide to go with a major investment a friend of mine just bought a kiwiprop and loves it. He said his light air performance picked up amazingly vs. The stock 3 blade fixed.

 

[sailcruiser]

We just bought an 11.0a and the prop is a 3 blade fixed 14" LH (pitch unknown at this point). That prop pushes us at 3.5kts at idle speed. At 80% it's about 6.2. I believe it is a MaxProp. It's a little scary trying to dock but it will stop the boat. SC

 

[Jtoben]

Thanks for the discussion. The "R14x8x1 (righthand rotation, 14 inch diameter, 8 inch pitch for 1 inch shaft. It cost about $550 in 2008." and the following comments helped me understand more. I just motored for 3 hours at 2600 RPM at 5.4 Knots (according to my ST60+)My Cell phone GPS app had me 7 knots. Control is the issue (My lack of control). When docking I enter the slip at about 2knots and as I close in to the dock if I off slightly the wind pushes back and I cant generate power fast enough to get the boat in reverse to correct. I know that there needs to be movement accross the Rudder to make the boat move. I just want more thrust on demand at a lower RPM. I have gotten better, but I am looking for the short burst power. I just figured if I was looking at a new prop, I would just get a folding prop. I just dont know the Rotation/Blade Diameter/Pitch/shaft diameter equation for the 11.0A. I was just looking for those numbers if anyone had an 11.0. That way I could compare all the options on the blade I would want. NOW, I am wondering if maybe just deal with what I have and put in a BOW THRUSTER (only kidding about the BT)... although it would help. Thanks again for the discussion

You might research a feathering prop if what you are looking for is the thrust and control in reverse. That changes the pitch of the prop so that it has the same pitch in reverse mode as it does in forward mode, thereby giving you the same control in reverse as when you are in forward. That is something a fixed and possibly a folding prop won't do. That was our problem with our 11.0 as well and why we pried open the wallet for the feathering Max Prop. We have the sail drive, so our specs wouldn't be helpful, but the reverse performance of the boat is amazing and in the tight confines of our marina and often windy conditions, really helpful. Be prepared for sticker shock. Max prop folks can help you with the right pitch and size for your boat and engine, and we actually returned ours for a one inch smaller size once we fitted it and decided we should have had more clearance.

 

[sailcruiser]

You might research a feathering prop if what you are looking for is the thrust and control in reverse. That changes the pitch of the prop so that it has the same pitch in reverse mode as it does in forward mode, thereby giving you the same control in reverse as when you are in forward. That is something a fixed and possibly a folding prop won't do. That was our problem with our 11.0 as well and why we pried open the wallet for the feathering Max Prop. We have the sail drive, so our specs wouldn't be helpful, but the reverse performance of the boat is amazing and in the tight confines of our marina and often windy conditions, really helpful. Be prepared for sticker shock. Max prop folks can help you with the right pitch and size for your boat and engine, and we actually returned ours for a one inch smaller size once we fitted it and decided we should have had more clearance.

Would you share specs for this prop? I do have a sail drive as well. A feathering prop is on my list just not this year. My wallet needs to heal from the boat purchase. This fixed prop is a monster on forward, fuzzy in reverse and a drag under sail. Thx! SC

 

[Jtoben]

Would you share specs for this prop? I do have a sail drive as well. A feathering prop is on my list just not this year. My wallet needs to heal from the boat purchase. This fixed prop is a monster on forward, fuzzy in reverse and a drag under sail. Thx! SC

The prop is spec'ed for your specific engine and sail drive. If you have the Volvo MD17C engine and Volvo Penta sail drive, I can get the specs next time I go to the boat and pull the file. If you have a different engine, our info wouldn't be helpful. Let me know.

 

[sailcruiser]

The prop is spec'ed for your specific engine and sail drive. If you have the Volvo MD17C engine and Volvo Penta sail drive, I can get the specs next time I go to the boat and pull the file. If you have a different engine, our info wouldn't be helpful. Let me know.

That is the exact setup we have. SC