I have an Alpha 1 drive with an aluminum propeller and want to go to stainless steel. I've noticed that there are quite a few mfgs out there and the prices for the same type of prop can fluctuate quite a bit. There is Mercury, Mercruiser, Appolo, Michigan Wheel, etc. Is there something in some props and not others that causes this? If anyone has any recommendations, I sure would appreciate it.
Propellers
- Thread starter RCJG228
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I can partially answer some of the questions:
Mercury's line of props is for outboards ( designed for their O/B's )
Mercruiser is for I/O. ( Usually for their power packs )
Don't know about apollo
Michigan Wheel is a "non-engine mfgr" maker of props of all sizes and types.
Prop manufacture is part science, part art. In all cases, you are making a complex metal device, that should meet rather stiff specs. Further, there are subtleties ( ie: cupping ) that will alter performance beneficially in some cases, but detrimentally in cases for which it is not designed.
Which is why I am going to point you to getting yourself to a professional prop shop, with a good reputation. A good prop shop will help you get the most from your boat, in the way you use it. There is no such thing as a "perfect prop for all boats/conditions", but they can fit you with one ( two? ) that will come very close. Then get to a prop scan shop and let them tune it...
Mercury's line of props is for outboards ( designed for their O/B's )
Mercruiser is for I/O. ( Usually for their power packs )
Don't know about apollo
Michigan Wheel is a "non-engine mfgr" maker of props of all sizes and types.
Prop manufacture is part science, part art. In all cases, you are making a complex metal device, that should meet rather stiff specs. Further, there are subtleties ( ie: cupping ) that will alter performance beneficially in some cases, but detrimentally in cases for which it is not designed.
Which is why I am going to point you to getting yourself to a professional prop shop, with a good reputation. A good prop shop will help you get the most from your boat, in the way you use it. There is no such thing as a "perfect prop for all boats/conditions", but they can fit you with one ( two? ) that will come very close. Then get to a prop scan shop and let them tune it...
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Don't know if this is copacetic but these guys are GOOD. They are used to handling people and companies from all around the US.
The Prop Shop in Mukilteo, WA (about 20 miles north of Seattle and 1 mile from the Boeing 747 plant). I had a couple pretty bent Volvo Penta Bravo III props straightened and tuned there. Good people.
http://www.propshopltd.com/
Marlin
Ps: It's a good idea to change out the alum prop and keep it for a spare. Mitch Evans (with Evans Marine in Lake Chelan), a retired Unlimited Hydro driver, said I'd be paddling my 24' Cobalt about 30 miles back from the looks of my SS props he took off from the 5" thick stick/log I cut in half if I had aluminum props. The blades would have been sheared off to a hub. As it was, there was some wobble but did no damage to the outdrive.
The Prop Shop in Mukilteo, WA (about 20 miles north of Seattle and 1 mile from the Boeing 747 plant). I had a couple pretty bent Volvo Penta Bravo III props straightened and tuned there. Good people.
http://www.propshopltd.com/
Marlin
Ps: It's a good idea to change out the alum prop and keep it for a spare. Mitch Evans (with Evans Marine in Lake Chelan), a retired Unlimited Hydro driver, said I'd be paddling my 24' Cobalt about 30 miles back from the looks of my SS props he took off from the 5" thick stick/log I cut in half if I had aluminum props. The blades would have been sheared off to a hub. As it was, there was some wobble but did no damage to the outdrive.
True Marlin, but a SS steel prop will transfer the impact to the shaft. If you damage something in the water with your prop, you need to have your shaft checked for damage, imbalance. Let unattended will cost big bucks down the road []err river.
Marlin, I called the propshop today, and the first question he asked me when I told him I was thinking of going to SS was "why". I told him that I thought I could increase performance and he said that unless I was having to have my aluminums rebuilt a few times a year from hitting stuff, that I would be wasting my money and realize no performance improvement from SS. I called the place where I have brought my aluminums to here in Chicago to have some occasional dings repaired, and they recommended 4 blade. They said the boat would handle better at low speeds and the performance would be about the same as a 3 blade. The propshop guy said a 4 blade is only good for wakeboarding, and should stay with a 3 blade. I don't know what to do.
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Define: "performance"
A 3-blade will give a better top end, and should give better economy. But a 4-blade would give a better "hole shot" at the cost of a lower top end, and slightly less economy ( more surface area = more drag, so a couple % economy drop ) Normally, you would not go to a 4-blade unless you had vibration issues, or had a very specific type of performance in mind. ( If you want high to end, theory sez a two blade is best! )
Note: My comments are very broad generalizations.
Sounds like the local guy wants to sell you a prop, but the other guy wants you to have the right thing. ( I could be wrong, but that is what it sounds like )
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That said, having your current prop tuned might give you all the performance that you need at considerably less expense.
A 3-blade will give a better top end, and should give better economy. But a 4-blade would give a better "hole shot" at the cost of a lower top end, and slightly less economy ( more surface area = more drag, so a couple % economy drop ) Normally, you would not go to a 4-blade unless you had vibration issues, or had a very specific type of performance in mind. ( If you want high to end, theory sez a two blade is best! )
Note: My comments are very broad generalizations.
Sounds like the local guy wants to sell you a prop, but the other guy wants you to have the right thing. ( I could be wrong, but that is what it sounds like )
--
That said, having your current prop tuned might give you all the performance that you need at considerably less expense.
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I didn't want to mislead you. The type of metal of your prop won't give you better performance - just more durability.
Also, obviously a harder prop (SS) will transfer the impact through to other components however I was AMAZED of the impact that outdrive would take and AMAZED the bearings would hold up like they did with the wobble of the bent props. I looked up right at the time the log went under my bow - almost exactly in the middle, perpendicular to the log so it hit the outdrive first and then got caught between the two props and CHOPPED it in half at 35 mph. I stopped to assess the damage and turned around and went back to look at the log and it looked like a stick of dynamite chopped it in half. Remember the Bravo III outdrive is a dual prop setup with the props spinning in opposite directions. Maybe Volvo Penta are a little more durable but I wouldn't want to hit something that would damage it.
As far as performance goes - props are really a touch and go thing. My opinion is it would really be a trial by error type thing - hard to say what something is going to do until to try this and try that and narrow it down to do what you want it to do. AND, after all that time and money you may end up with what you have now.
Performance can be defined by torque or top end speed and/or anything in between.
But, one thing is for certain - SS is more durable than aluminum. Thus the reason for my recommendation of getting whatever you end up with in SS and keep you aluminum for a spare (besides, it's lighter than SS in case you have to change it in the water).
Also, obviously a harder prop (SS) will transfer the impact through to other components however I was AMAZED of the impact that outdrive would take and AMAZED the bearings would hold up like they did with the wobble of the bent props. I looked up right at the time the log went under my bow - almost exactly in the middle, perpendicular to the log so it hit the outdrive first and then got caught between the two props and CHOPPED it in half at 35 mph. I stopped to assess the damage and turned around and went back to look at the log and it looked like a stick of dynamite chopped it in half. Remember the Bravo III outdrive is a dual prop setup with the props spinning in opposite directions. Maybe Volvo Penta are a little more durable but I wouldn't want to hit something that would damage it.
As far as performance goes - props are really a touch and go thing. My opinion is it would really be a trial by error type thing - hard to say what something is going to do until to try this and try that and narrow it down to do what you want it to do. AND, after all that time and money you may end up with what you have now.
Performance can be defined by torque or top end speed and/or anything in between.
But, one thing is for certain - SS is more durable than aluminum. Thus the reason for my recommendation of getting whatever you end up with in SS and keep you aluminum for a spare (besides, it's lighter than SS in case you have to change it in the water).
Bill, I have read that an aluminum prop deflects or bends, so I was looking to minimize that. I am experiencing a minor vibration, and asked my local prop shop about prop scan, and was told they don't do them on outdrive props because of cost. I haven't hit anything, and there aren't any dings on it. I plan on having the marina look into the vibration when I pull it out for the winter, but I want to eliminate the possibility that the prop is the culprit. I thought that SS might be a better balanced prop. I have also noticed that the finish on the blades has gotten rough, and I don't know what that is. It doesn't seem like build up of algae or marine growth. It was a brand new prop 2 years ago when I installed it, the blades were smooth as glass. When I run my fingers over the blades, it feels like textured paint. I thought it might be an electrical discharge thing; I checked my anodes and they look ok.
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Richard,
In response to the flex - I can't respond to that but I know you aren't going to get any flex out of SS. Regarding the rough finish though, when I bought the two new props I noticed the finish of the new SS props were a very dull finish however they were brand new VP SS props - I say the sealed VP box they came out of. I asked Mitch Evans if he made a mistake and was putting on aluminum and he said no, they were SS. My old ones were shiny and bright. He said the water will actually polish them smooth - HE WAS RIGHT, especially salt water, but even the lake worked on polishing them up. They were bright in about one month. He said they used to polish new props for the hydro and put something on the prop to reduce drag. Remember, an unlimited hydro uses a two bladed SS prop designed to have one blade in the water at all times. That's top end performance!
In response to the flex - I can't respond to that but I know you aren't going to get any flex out of SS. Regarding the rough finish though, when I bought the two new props I noticed the finish of the new SS props were a very dull finish however they were brand new VP SS props - I say the sealed VP box they came out of. I asked Mitch Evans if he made a mistake and was putting on aluminum and he said no, they were SS. My old ones were shiny and bright. He said the water will actually polish them smooth - HE WAS RIGHT, especially salt water, but even the lake worked on polishing them up. They were bright in about one month. He said they used to polish new props for the hydro and put something on the prop to reduce drag. Remember, an unlimited hydro uses a two bladed SS prop designed to have one blade in the water at all times. That's top end performance!
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S/S is harder, stiffer and more durable than aluminum. Virtually all boats in this neighborhood use SS because soft groundings are an "everyday" occurrence. about 50% of the area is less than 6 ft deep at median tide, so plowing through a bit of sandy mud is common. We call it "polishing the props". It is also why most I/O and O/B skegs have no paint. An AL prop lasts about one trip...
In other areas where the bottom is less forgiving ( ie: rocks ) I can understand the desirability for AL props.
In any event, AL wil flex more than SS, and as a result, SS will give better performance because it a) holds it's shape better and b) the blades can be thinner for the same power.
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If you have vibration you need to have it properly checked and fixed. This is not an option, as the vibration will kill the remainder of the power train.
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"asked my local prop shop about prop scan, and was told they don't do them on outdrive props because of cost."
If your Prop shop is in WI, then that means PropScan is a competitor... Call a PropScan shop and ask about the cost to scan. The one in Chicago has a toll-free: 800 339 7767
I've never heard of not scanning an outdrive prop...
In other areas where the bottom is less forgiving ( ie: rocks ) I can understand the desirability for AL props.
In any event, AL wil flex more than SS, and as a result, SS will give better performance because it a) holds it's shape better and b) the blades can be thinner for the same power.
--
If you have vibration you need to have it properly checked and fixed. This is not an option, as the vibration will kill the remainder of the power train.
--
"asked my local prop shop about prop scan, and was told they don't do them on outdrive props because of cost."
If your Prop shop is in WI, then that means PropScan is a competitor... Call a PropScan shop and ask about the cost to scan. The one in Chicago has a toll-free: 800 339 7767
I've never heard of not scanning an outdrive prop...
Bill, the one in Chicago is the one that said they don't do the prop scan on an outdrive prop. They are also where I have brought both of my aluminums to be reconditioned.
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If you have vibration you need to have it properly checked and fixed. This is not an option, as the vibration will kill the remainder of the power train.
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This vibration is what is driving this alum/SS decision. I want to eliminate the chance that it is the prop.
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If you have vibration you need to have it properly checked and fixed. This is not an option, as the vibration will kill the remainder of the power train.
--
This vibration is what is driving this alum/SS decision. I want to eliminate the chance that it is the prop.