Would you recommend a 3-bladed prop for a Yanmar YSM12 diesel? If so what size prop would you recommend?
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MaxProp
Jaan. 2, 2000 Dear Phil, I'm not enough of a gear head to recommend an actual prop size, but PYI is, and I can't recommend highly enough their 3 bladed MaxProp. Because it has three blades that can be pitched to suit your boat and engine you can adjust it using PYI's recommendations to give good power at a reasonable RPM and fuel consumption rate. The three bladed design is very well balanced and so vibration is minimal. Furthermore, the three blades give good solid power to help punch to windward in a chop. Because it feathers it reduces drag under sail and so will add 1/2/ to 3/4 of a knot to your boat speed compared to a fixed 2 or 3 blade prop in similar conditions. The real joy is when backing down, because the prop blades swivel to give virtually the same power in reverse as they do in forward. In Marina Mazatlan we backed out of our slip just as another vessel entered the dock row we were on. Rather than back straight out and cause the other boat an obstruction I made a 90° turn to starboard and backed down the row to get to the wider channel that would allow an easier turn, where after making another 90° turn I encountered three more approaching boats. I decided to just keep backing up at low speed. By the time I cleared the other three boats I was half way along the length of the marina, and so decided I might just as well carry on and steered the rest of the way to the fuel dock in reverse where we backed in, doing 2 more 90° turns to get there. I didn't think much of it while I was doing it but a sailor on the seawall above the marina had seen this entire performance and came up to me at the fuel dock and jocularly said I was making the rest of them look bad, having just backed through the entire marina! I was startled by the vigour of his comments because I genuinely didn't think backing down was any big deal. It was only later after considering the comments of other sailors discussing how poorly their boats reversed that I really appreciated the advantage the Max Prop gave me in this extended manouver in reverse. You should also know that many top of the line manufacturers ( Swan, Oyster, etc.) equip their boats with MaxProp as standard equipment. Other than adding sail area I can't think of anything that will more dramatically improve performance than a feathering prop, and additional sail area isn't any help in reverse! Fair winds, Brian Pickton of BeneteauOwners.net aboard The Legend, Rodney Bay, St.Lucia
Jaan. 2, 2000 Dear Phil, I'm not enough of a gear head to recommend an actual prop size, but PYI is, and I can't recommend highly enough their 3 bladed MaxProp. Because it has three blades that can be pitched to suit your boat and engine you can adjust it using PYI's recommendations to give good power at a reasonable RPM and fuel consumption rate. The three bladed design is very well balanced and so vibration is minimal. Furthermore, the three blades give good solid power to help punch to windward in a chop. Because it feathers it reduces drag under sail and so will add 1/2/ to 3/4 of a knot to your boat speed compared to a fixed 2 or 3 blade prop in similar conditions. The real joy is when backing down, because the prop blades swivel to give virtually the same power in reverse as they do in forward. In Marina Mazatlan we backed out of our slip just as another vessel entered the dock row we were on. Rather than back straight out and cause the other boat an obstruction I made a 90° turn to starboard and backed down the row to get to the wider channel that would allow an easier turn, where after making another 90° turn I encountered three more approaching boats. I decided to just keep backing up at low speed. By the time I cleared the other three boats I was half way along the length of the marina, and so decided I might just as well carry on and steered the rest of the way to the fuel dock in reverse where we backed in, doing 2 more 90° turns to get there. I didn't think much of it while I was doing it but a sailor on the seawall above the marina had seen this entire performance and came up to me at the fuel dock and jocularly said I was making the rest of them look bad, having just backed through the entire marina! I was startled by the vigour of his comments because I genuinely didn't think backing down was any big deal. It was only later after considering the comments of other sailors discussing how poorly their boats reversed that I really appreciated the advantage the Max Prop gave me in this extended manouver in reverse. You should also know that many top of the line manufacturers ( Swan, Oyster, etc.) equip their boats with MaxProp as standard equipment. Other than adding sail area I can't think of anything that will more dramatically improve performance than a feathering prop, and additional sail area isn't any help in reverse! Fair winds, Brian Pickton of BeneteauOwners.net aboard The Legend, Rodney Bay, St.Lucia
Prop
Maxi props are a bit spendy for me. I can tell you that on my YSE12 Yanmar I use a 12x12 three blade prop. I easily do 5.5 knots at 3/4ths trottle. I can do over 6 in a pinch. Knotmeter is proberly calibrated and generally matches GPS. Hope this helps. Sean s/v Carnaby Street
Maxi props are a bit spendy for me. I can tell you that on my YSE12 Yanmar I use a 12x12 three blade prop. I easily do 5.5 knots at 3/4ths trottle. I can do over 6 in a pinch. Knotmeter is proberly calibrated and generally matches GPS. Hope this helps. Sean s/v Carnaby Street
Prop for Hunter 30
Dear Phil, Thanks for the note. Our records show the your boat should be equipped with a 13 x 8 three blade, with your listed engine. This can be confirmed by providing to me the current two blade specs. Any engine transmission combination is capable of utilizing a three blade. In order to compensate for the additional load, the third blade produces, you will need to reduce the three blades overall pitch. This should in theory produce the same load to the engine but at a higher efficiency rate. You should experience a smoother run and greater ability of maintaining speed when you are powering into a heavy wind or sea. Hope this helps. P.S. I totally agree with Brian Pickton’s comments!
Sincerely, Kevin L. Woody
Dear Phil, Thanks for the note. Our records show the your boat should be equipped with a 13 x 8 three blade, with your listed engine. This can be confirmed by providing to me the current two blade specs. Any engine transmission combination is capable of utilizing a three blade. In order to compensate for the additional load, the third blade produces, you will need to reduce the three blades overall pitch. This should in theory produce the same load to the engine but at a higher efficiency rate. You should experience a smoother run and greater ability of maintaining speed when you are powering into a heavy wind or sea. Hope this helps. P.S. I totally agree with Brian Pickton’s comments!
Sincerely, Kevin L. WoodyThe boat I have is a 1979 30' Hunter. The prop on it right nonow is a 13x10. What I'm looking for is more power. I know I'm not going to get more speed, I just want to be able to deal with the current and weather.
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