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Pat Taylor
Prop Sprint
We have a 1975 Hunter 30 with a Universal M25XP diesel and a 3 bladed prop. Lots of torque but, especially in reverse, we still have severe prop walk that is more like a sprint than a walk. You learn to work with it. Pat Mystic
We have a 1975 Hunter 30 with a Universal M25XP diesel and a 3 bladed prop. Lots of torque but, especially in reverse, we still have severe prop walk that is more like a sprint than a walk. You learn to work with it. Pat Mystic
I was told that just about every keelboat has some prop walk, it's just a question of how much and in which direction. You just have to learn how much "walk" your boat has and work with it. I found out that it can be quite useful for turning and docking in tight situations. Have fun! Peter
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Tom
Any right handed prop will walk to port. You have to learn to compensate for this tendency when maneuvering under power.
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Mike Layman
I just put a 3 blade prop on my 1981 Hunter 30 with a Yanmar 2gm13 motor this sping. Went from a 16X9 2 blade to a 15X9 three blade. I would would say that the prop walk is twice as much as before. Before, I could turn to starboard while reversing slowly. Now, can not turn to starboard while reversing slowly but it will turn to starboard when moving a little faster. The stopping power while moving forward then reversing is very good with the three blade. It's ok for me since I learned to use it for my advantage. It even comes in handy once in a while. Mike Layman Corpus Christi, TX
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Ray
As a new owner of a 30 I too found the prop walk excessive until I was shown how to power up immediately so as to give the rudder something to bite against, then go to idle and the boat seems to steer perfectly well after gaining astern momentum from the initial high revs. Otherwise the boat seems uncontrollable going astern. I'm more impressed with this technique each time I use it. Lots of astern power for just a few seconds then idle. Seems to work.
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Tim
3 blade vs. 2
I went from a 2 blade 13x13 to a 3 blade 13x10 to a 3 blade feathering 13xwhatever. The biggest problen is that hull clearance; the 1981 Hunter 30 I have is 8" from shaft center to hull. If you go less than a clearance of 15% of the diameter of prop, you will get lots of prop walk, even in forward; and maybe more cavitation. Ideally, it ought to be 20%. Fifteen percent makes for a 13" prop, less than the reccomended 15". The feathering prop I have has a reverse pitch independently adjustable from the forward pitch so you can compensate for the lack of a reduction gear in reverse and get a ton of thrust. Then the technique Ray describes is exactly right. Above 1 kt or so it's well behaved.
I went from a 2 blade 13x13 to a 3 blade 13x10 to a 3 blade feathering 13xwhatever. The biggest problen is that hull clearance; the 1981 Hunter 30 I have is 8" from shaft center to hull. If you go less than a clearance of 15% of the diameter of prop, you will get lots of prop walk, even in forward; and maybe more cavitation. Ideally, it ought to be 20%. Fifteen percent makes for a 13" prop, less than the reccomended 15". The feathering prop I have has a reverse pitch independently adjustable from the forward pitch so you can compensate for the lack of a reduction gear in reverse and get a ton of thrust. Then the technique Ray describes is exactly right. Above 1 kt or so it's well behaved.
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