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Alumacraft competitor 175 /honda 150 speed? - Page 3 - Walleye Message Central
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  #21  
Old 09-30-2021, 06:16 PM
Bone-fish Bone-fish is offline
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So I'm curious as to the discrepancy of the 3 blade 17 versus the 4 blade aluminum I see in your photo. So let's assume your not running a four blade prop which would require more energy to turn more weight, and are using a 3 blade 17p. When I dropped from a 3 blade 19 p to a 4 blade stainless on my merc, I lost about 4/5 mph. But the grip in the turns for pulling tubers as well as getting on plane with a fully loaded boat while pulling people was more than an even trade. Plus on a windy day, and current, hands down the revolution 4SS 4 blade prop was just the best purchase I've made. Who cars a out 4/5 mph when you gain all that torque and control. Easy decision for me.

Back to your original question. It's likely the 19p will give you the in reader you want, but only after you're on pane. Add SS for more grip especially when coming on plane or when turning. Less flex = more bite, but also as others have said they can cup the blades fir better performance without deflection.
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  #22  
Old 09-30-2021, 09:12 PM
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RMBin303 RMBin303 is offline
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Quote:
Originally Posted by REW View Post
Jethro,
Sorry, not necessarily.

Simply put, if you have two identical props - one made of aluminum and one made of stainless, one will have virtually identical speeds.

However, if one has a stainless prop that uses thinner blades, a higher rake angle and possible other changes - then one can certainly get a bit better performance with a stainless prop.

But, the very big advantage of the stainless prop is durability. If you have a low speed bottom strike with a stainless prop, you are likely to have no damage on the stainless prop. However, if one had the same low speed bottom strike on an aluminum prop, one would very likely have a badly damaged prop.

But, if one has a high speed or wide open hard bottom strike, you are likely to destroy the lower unit as well as either prop.

Best wishes.
Sorry, but this is bad advice. Two props of different material will not perform the same. The aluminum will likely give a better hole shot, while the stainless will almost certainly have better top end. It has to do with the flex of the material. Flex benefits hole shot as it increases RPMs during hole shot. Flex loses in top end. Al will flex more than stainless.

And no, you are not likely to destroy the lower unit with a hard strike. That is what the hub of the prop is for. It will "spin", sacrificing the hub, and saving the lower unit. Many years ago, I hit something hard enough with a High-Five stainless prop that it wasn't salvageable. The lower unit was fine.
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  #23  
Old 10-01-2021, 09:46 AM
REW REW is offline
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RM,
Just a thought for discussion.
If you have an aluminum prop that is made thick enough - not to flex, and the stainless prop is made the same thickness - I really believe that the props will perform in an identical fashion.

For many years, OMC produced props made this way. i.e. thick tough aluminum props - and the identical props made of stainless steel. Over many many motors and many years - virtually identical performance.


With respect to a HARD high speed bottom strike - I am speaking of hitting a rock that is one incch below the water line when running flat out with a 150 hp motor going 50 mph.

After the bottom strike - there is no lower unit on the bottom of the power head. So, in this case, it makes 0 difference as to what propellor that was on the end of the prop shaft because the lower unit and prop and shaft is at the bottom of the lake.

This is my definition of a HARD high speed bottom strike that will make no difference as to the prop that is on the bottom of the engine.

But, from a practical point of view where aluminum and stainless props are not identical and where high speed bottom strikes are not as severe - as I just pictured; you are 100% correct in that the stainless prop runs better and survives bottom hits much better than an aluminum prop.

Furthermore I agree with you to the point that I run ONLY stainless steel props on all of my outboard motors - no matter the size. I have gone years with low speed bottom strikes once in a great while and I have not had to have any props rebuilt because there was no significant damage to the stainless props under these conditions.

Also, Yes, to the performance question. I don't run stainless props that are identical to aluminum props but rather props that are designed to work the best for my particular rig and have the performance advantage of the better prop design, and the thinner blade that simply continues to give me very good performance for every time that I take the boat on the water.

Take care
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  #24  
Old 10-01-2021, 10:24 AM
3M TA3 3M TA3 is offline
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Same motors, although 10 years old, got 45-46 with Lund 1825 Explorer Sport. Switched to SS and got same speeds but hole shot was superb. Sold boat last year. Oh yeah. 2, 3, 4 in boat made no diff on top speed. Top RPM was 6200.
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  #25  
Old 10-01-2021, 10:42 AM
3M TA3 3M TA3 is offline
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Different boat but I used a PowerTech OFS 15.25" x 19
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  #26  
Old 10-02-2021, 06:58 AM
DW DW is offline
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Quote:
Originally Posted by REW View Post
DW,
Motor height is part and parcel of prop selection.

Some prop designs required that the motor be run deep into the water to maximize its performance.

Other props, however - for example ones with a high rake angle can run with the props nearly out of the water and do it very well.

So, in reality, every prop that is put on a boat should have the motor height optimized for that prop, and also for the current conditions of the wind and waves at the time of its running.

Hence, if one is really going to optimize the speed of a boat, and the ability to run a number of different props, the boat and motor should have an electric hydraulic - on the fly adjustable jack plate.

The height of the motor, in the same fashion as the trim of the motor should be adjusted on the fly to optimize the running of the rig - depending on the throttle setting, the force of the wind, the height of the waves, the temperature of the air and the temperature of the water. All of these things can be optimized for each propellor. In addition, when all of the different props that can be run on a motor - are run in different conditions, there will be one clear winner that will be the best prop to run for that desired speed, that specific temperature of air and water, that specific throttle setting and that specific wave height.

Best wishes.
Theoretically, I agree that prop choice may impact optimum motor height. However, unless an owner lives on a lake and has the patience and resources to evaluate dozens of props while tweaking motor height, I suggest your advice is unrealistic. I suggest that most rigs come out of the dealer with the motor too low. Until an owner experiments with height there is no way to know the optimum height. Until optimum height is achieved there is no possibility of optimizing prop selection. There is a little of the chicken or egg question when evaluating height and prop selection, but most owners will never optimize performance until proper height is determined first.
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  #27  
Old 10-07-2021, 01:03 PM
REW REW is offline
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DW,
Copy that.

However, one part of my post suggested the installation of a jackplate - preferably one that could be used while underway.

That way, one can adjust the motor trim and the motor height as needed to optimize the boat, motor, prop combination for any situation that might ever be encountered.

An easy thing to do, and very realistic.

Considering that folks are paying prices north of $50K these days, what is another 1-2K in the deal?

Best wishes
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  #28  
Old 10-12-2021, 08:23 AM
DW DW is offline
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A jackplate is a great idea. However, owners should verify use of a jackplate is permitted. Due to increased leverage by the offset of a jackplate, some manufactures will not honor warranties when used. Many transoms are not designed to handle the additional forces. I donít use one for this reason.
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  #29  
Old 10-14-2021, 05:20 AM
troller71 troller71 is offline
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you have a 40 mph boat
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  #30  
Old 10-16-2021, 06:17 AM
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the only way I know that would gain speed would ultimately raise your rpm's. as your running the max rpm's for that motor even if you lighten your load and gain 3 mph it's also going to put you over the 6000 mark. even going to a ss prop ultimately if it turns more rpm's to raise your speed you haven't gained anything. at most it might gain you 2 or 3 mph. is it worth it to start changing things for that small increase. when do you need to run over 45 mph? i say leave it alone if your getting 6000 rpm and getting a decent holeshot. just my opinion tho.
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