Stainless vs. Aluminum

[bear_69cuda]

Morning,

About my 1999 Bayliner 1950 3.0 L MerCruiser that gets to ~42 mph @ 4800 RPM with 21 pitch aluminum stock prop.

If I find a stainless prop (say a 20"P Apollo or Stiletto) that lets my engine get to 4800 rpm. Will I notice any significant difference?

Maybe I should just get a second Aluminum for a spare?

Opinions?

Advice?

Thanks in advance!

Have a great day............

Snowed yesterday! =-( It's gonna be a long winter waiting for lakes to thaw!

 

[MikDee]

Re: Stainless vs. Aluminum

Morning,

About my 1999 Bayliner 1950 3.0 L MerCruiser that gets to ~42 mph @ 4800 RPM with 21 pitch aluminum stock prop.

If I find a stainless prop (say a 20"P Apollo or Stiletto) that lets my engine get to 4800 rpm. Will I notice any significant difference?

Maybe I should just get a second Aluminum for a spare?

Opinions?

Advice?

Thanks in advance!

Have a great day............

Snowed yesterday! =-( It's gonna be a long winter waiting for lakes to thaw!

Your WOT rpms seem a bit high? shouldn't they be 4600rpm Max?

 

[Silvertip]

Re: Stainless vs. Aluminum

In my view there is no reason to change from aluminum to stainless unless the current prop is damaged beyond repair and you actually need a new prop or unless you are trying to extract the ultimate in performance from the boat. Stainless generally provides some performance increase but the degree of increase (or decrease in some cases) can't be predicted with any reasonable accuracy and only comes from testing. So the net result is you can spend a fair amount of money for a marginal increase in performance. Ignore the lower unit damage discussion that goes on over aluminum vs stainless. If you hit something hard enough, lower unit damage will occur regardless what prop you are running.

 

[bear_69cuda]

Re: Stainless vs. Aluminum

Max rpm for my 3.0 is 4800 per data plate on air-cleaner, and per Bayliner.

My plan was stainless for main prop, then use my aluminum for a spare. My current prop is close to perfect condition. Regardless I need to get a second prop for a spare... I would like to get all I can from the 3.0 since there are no real tweaks for this engine. All and all, the two times I've even driven this boat, I was very happy overall... Since I don't have the cash to test multiple props.. I should get an aluminum spare?

 

[MikDee]

Re: Stainless vs. Aluminum

Ok, IMO, Instead of a 20" Apollo, or Stiletto, maybe a 19" pitch, usually a drop of 2" pitch is required because stainless will make your engine work harder, in order to keep your rpms the same, another thing I've found is hole shot is not as good for this same reason, but even with the same rpms it will be faster because stainless blades are thinner, & don't flex as much. A plus I found with stainless, you can usually trim out more with less ventilation. Hole shot can be improved with ventilated props (small strategically placed holes, & rubber plugs, in the hub by the manufacturer).

 

[Bondo]

Re: Stainless vs. Aluminum

All and all, the two times I've even driven this boat, I was very happy overall... Since I don't have the cash to test multiple props.. I should get an aluminum spare?

Ayuh,...

Considering the boat, it's powerplant,+ your overall Happiness with it...
I'd just go find a copy of the prop you have Now...

 

[bear_69cuda]

Re: Stainless vs. Aluminum

All,

Thanks for the advice!

I think I'll get a exact copy of what I have. I know the last number in the hub is 21. That = 21" pitch. Is there a way to determine what brand the prop is? I see no manufacture name, nothing other than numbers and letters...

Best regards,

 

[steelespike]

Re: Stainless vs. Aluminum

When changing brands style and material all bets are off.Usually a SS will improve overall performance but this is not absolute.There is a post here where they went from aluminum(performing well) to SS same pitch lost rpm,speed and developed blow out when none before.This would be the extreme but an example of the uncertanty.You migfht check out the Hustler turning point.Aluminum that delivers close to SS performance at Al. prices.
I would say you are darn close to the max you will see with your setup.
Even if you get the perfect prop I wouldn't expect more than a mile or 2 increase.Don't forget in a quest for more speed hole shot may be lost.
Is your speed by gps?

 

[bear_69cuda]

Re: Stainless vs. Aluminum

My speedo on the boat and fishfinder said 44... No GPS... So subtracted a few mph cuz I figured they were most likely a tad high... I figured thats in the ball park?
Definitely stayin aluminum 21"P... Why mess/gamble with something that isn't gonna gain any substantial results...

 

[Bondo]

Re: Stainless vs. Aluminum

Is there a way to determine what brand the prop is? I see no manufacture name, nothing other than numbers and letters...

Ayuh,....

If it's 48-Something or rather-21,....
It's the original Mercruiser prop....

 

[180shabah]

Re: Stainless vs. Aluminum

For the same money as anotherb "black max"(the merc prop) I would get a Hustler from turning point. This was the first prop I purchased for my boat and the difference was huge. it is vented - the hole shot improved noticably. I also experienced less ventilation in turns and a higher top end at the same RPM. Get one of these, make your current prop the spare and never look back untill you are ready to pop for a shifting prop.

 

[bear_69cuda]

Re: Stainless vs. Aluminum

Thanks!

I'll check out the Hustler prop! Same 21"P as my current prop correct?

What is a shifting prop?

 

[180shabah]

Re: Stainless vs. Aluminum

For the Hustler, use the same pitch you have now if your WOT RPMs are correct.

A shifting prop is just that, a prop that shifts or changes pitch. Some shift at a certain RPM(adjusted by changing spring tension) and some shift gradually, keeping your engine in it's powerband, much like a CVT in a car. They are expensive, but you get a low starting pitch for good holeshot or watersports towing AND a higher final pitch for top speed without over-reving the engine.

 

[bear_69cuda]

Re: Stainless vs. Aluminum

Cool,

I need to see how these work?

How expensive are they? I'll check in the marine store...

Have a great Thanksgiving all!

 

[180shabah]

Re: Stainless vs. Aluminum

You will not find these in stores. As far as I know there is only one shifting prop still in production, the Power Pitch from Aerostar Marine. Plan on spending $2k for one of these.

The others: Torque-Shift from Land-n-Sea and the Quicksilver Powershift are only available used. They range in price but expect to pay $300-500 for one in good condition. The torqueshift is much more tunable, It starts at 11" and can have a final pitch anywhere from about 19" up to 26". However, it has many wear parts that are just not available. The powershift is a much simpler design, but you can only adjust the RPM when the the fixed 6" shift happens.

The torqueshift has a gradual increase in pitch that is controlled by both springs and changable cams. The powershift is a "hard" shift that feels more like an automatic transmission in a car.

 

[bear_69cuda]

Re: Stainless vs. Aluminum

Holy smokes!

2K for a prop...

I think I'll stick with your advice and go for the Hustler for $135.00

I did some reading on shift props! Sounds great, but with this being my first boat, and only a 3.0 L... I could never justify it...

Thanks again for your time!

 

[bear_69cuda]

Re: Stainless vs. Aluminum

Morning,

I posted info from my findings on the Bayliner fourm yesterday. That I was going for the same 21"P Hustler aluminum prop. One of the members posted the following and now I'm confused. I think if 4-5 mph gain is possible from a stainless prop, it's significant... See quote below. I'm asking him if he lost the hole-shot the aluminum had, if the stainless is progressive, and what brand. I'm confused now.

"just my 2 cents..i have an 02 19ft bayliner br with the 3.0 it came with an aluminum prop 21 pitch..i put a 21 ss and gained a good 4-5 mph at the same rpm"

Happy Thanksgiving!

 

[a70eliminator]

Re: Stainless vs. Aluminum

Don't let that bother you, probably had the wind at his back that day, a few MPH + or - can be the result of current, wind, chop, load, temp and humidity, unless you quick change the prop and experiment under identical conditions the end result can be misleading, I think I said that right. One day on lake I noticed I could get up 49MPH while heading towards the dam, then heading back in I could only get about 46 MPH.

 

[bear_69cuda]

Re: Stainless vs. Aluminum

Thanks for the reinforcement,

I'm still going with the Hustler Aluminum prop...

It would be fun to see if any marinas around here would let me try a few props before I purchased one... Maybe next time...

 

[sleeper]

Re: Stainless vs. Aluminum

Thanks for the reinforcement,

I'm still going with the Hustler Aluminum prop...

It would be fun to see if any marinas around here would let me try a few props before I purchased one... Maybe next time...

The hustler is a good deal. I replaced my factory black max prop with a hustler and the hole shot and top end both improved. Its hard to beat for the money.