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Posts: 281
| Hey Guys and Gals- I have a Ranger 618vs. Looking for a prop for Canada. Not Stainless. We always seem to hit something up there. What size, pitch, brand do you recommend?
Thanks For The Help
Chad |
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Posts: 5874
| As you are not interested in absolute performance, I'd go with an inexpensive aluminum, like a 3 blade Merc Bravo. Pitch the same, or one higher. So if you have a 17P, I'd go to a 19P. |
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Posts: 1096
Location: Hayward, WI | Mercury Alpha 4, 4 bladed aluminum is a good performing alternative to SS. |
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Posts: 192
| I found this from the Mercury website:
Will a stainless steel propeller damage my lower unit in the event of an underwater impact? Mercury engineers, conducting underwater impact testing, found no substantial difference in the amount of torque transferred to the propeller shaft between an aluminum and stainless steel propeller. Mercury’s Flo-Torq II hub system is designed to give way during an underwater impact – protecting the outboard and still providing you the ability to idle home safely.
http://www.mercurymarine.com/propellers/about/how-to-choose/stainle...
Watch the video on the link above.
I've seen similar statements made at various other websites as well. Seems to make sense to me from an engineering perspective but I am a Civil Engineer, not a Mechanical Engineer so take that for what it is worth. Most people will assume the aluminum prop will give when hitting something preventing or reducing engine damage.
Edited by LarryO 5/12/2014 7:11 PM
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Posts: 1283
| Wonder when they started using that hub. |
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Posts: 192
| Not sure but I can say my model year 2000 Optimax 150 had it and my current motor, model year 2007 Optimax 150 also has it. |
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Posts: 1283
| Mines a 95, Ill have to look at it and see what I have. |
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Posts: 1096
Location: Hayward, WI | They have used that hub for many years, they may claim it prevents damage but I can tell you first hand that it does not. It might be better than the old all rubber hub but I have seen plenty of bent propshafts and damaged gears when the FT 11 hub is used. |
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Posts: 192
| kjgmh - 5/14/2014 9:05 AM
They have used that hub for many years, they may claim it prevents damage but I can tell you first hand that it does not. It might be better than the old all rubber hub but I have seen plenty of bent propshafts and damaged gears when the FT 11 hub is used.
In general I can agree with that. During some slow speed collisions it might help but for any higher speed impact, not likely. But the same goes for using an aluminum prop. It won't prevent lower unit damage either. I have personal experience with that one. That whole theory of the aluminum prop folding up and absorbing energy, preventing it from being transferred to the lower unit doesn't make any sense from an engineering perspective.
The real advantage to using the aluminum prop for a Canadian trip is it prevents damage to your nice (expensive) stainless prop.
I guess the only real way to prevent lower unit damage is, don't run into rocks. |
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