Aluminum Versus S/S Same or Not ?

[Mike Cherry]

Is there anything wrong in changing from a Aluminum 19 pitch to a 19 pitch S/S ? I was told that a 19 pitch was a 19 pitch no matter if it is Aluminum or S/S ... Is this correct ? I have a 2004 1903 CC Trophy powered with a 2004 150 Mercury opti max. I have no issues with the power in the hole or WOT with the aluminum but would like to change to a S/S. I use the boat for Scuba diving so carry heavy loads at times with 4 men and tanks and gear. My RPM gage stopped working at the end of the summer and I cannot remember what the rpm was at WOT with my crew and gear. I am working on getting the RPM fix. If i do not have the rpm info can I just change to the S/S? Thanks in advance for the help ...... tks

 

[Bondo]

Re: Aluminum Versus S/S Same or Not ?

Is this correct ?

Ayuh,... Sorta....

You might loose a few rpms, but til ya fix the tach, ya won't know for sure...

 

[jkust]

Re: Aluminum Versus S/S Same or Not ?

There is more to a prop selection than just material that could increase or decrease performance. From first hand experience, things like a prop of the same pitch and material but more cupping can reduce RPM's.

 

[tpenfield]

Re: Aluminum Versus S/S Same or Not ?

Sort of apples and oranges, even though the pitch would be the same. The blades on the SS will be thinner, perhaps have more rake, cupping and other design features. Trail with errors may be the only way to tell the difference.

 

[cyclops2]

Re: Aluminum Versus S/S Same or Not ?

If you just replace a Aluminum prop with the EXACT same prop shape & size in SS. It should run the exact same way.

If you take advantage of the BASIC DIFFERENCE between Aluminum & SS.

The SS SHOULD be thinner in each blade thickness. So the SS COULD be LOGICALLY better in some things.
NOT ALL THINGS.

The problems come up if no one REALLY knows all the little unseen curves in the original prop that is designed to do a lot of different running conditions well.
Enter a SS that is designed for Holeshots or WOT increases. It sure gave up something to get noticeably better in 1 area.

4 big divers and gear ? Be VERY leery of a SS making a difference in everything the Aluminum does.

You do know SS props break drive parts faster than most Aluminum ? Generally speaking.

 

[steelespike]

Re: Aluminum Versus S/S Same or Not ?

You really need your present performance, rpm and speed lightly loaded and with your typical load. with boat details.
There are al props that do very well. If you have an aluminum prop that is doing very well The ss will be less likely to make a big difference. The change could be a few tenths to a few mph. Ss can cost 3 times as much to buy and I believe twice as much to repair.
They do hold up better against soft contacts,ie sand or mud but if your likely to make hard contact you could need a prop repair.
While a cushion hub should help in a hard contact there is still no doubt a ss prop can transmit more force to the drive line
when a al prop would likely just crumple.

 

[catfishr1]

Re: Aluminum Versus S/S Same or Not ?

Hi Mike ; I have been watching this thread since started. Resisted posting cause fig. I will get blasted. But here goes. I beleave it is a personal preference. Agree with most of what's been posted. I ran aluminum until 2011. I know will run s s from now on. Night &day for me. A side note only time had to have lower unit r&r 2008, aluminum prop.

 

[riskibusiness]

Re: Aluminum Versus S/S Same or Not ?

Hi Mike ; I have been watching this thread since started. Resisted posting cause fig. I will get blasted. But here goes. I beleave it is a personal preference. Agree with most of what's been posted. I ran aluminum until 2011. I know will run s s from now on. Night &day for me. A side note only time had to have lower unit r&r 2008, aluminum prop.

yes you can still bust your outdrive with an alum prop. But you are more likely to do damage with a s.s. prop. So for me it depends on the water I'm running in. If i'm going to Lake of the Ozarks or Carlyle Lake I run stainless. But for almost everywhere else in my area I use aluminum. (rivers,small lakes, etc.)

 

[cyclops2]

Re: Aluminum Versus S/S Same or Not ?

Great & correct logic riskibussiness.

 

[catfishr1]

Re: Aluminum Versus S/S Same or Not ?

Well can not say I was blasted. but do beleive door has been opened for debate. Oh boy, love a good debate. do not wish to hijack thread but think this gives 2 points of view for Mike. I love logic & resisted going to s.s. because logicaly s.s. would damage drive parts quicker than aluminum. That is not necessarily the reality of it. The reality is if any part of the fail safe for prop. fails i.e. hub, trim tab. then does not matter weather it is al. or s.s. And yes it is better for lower unit parts to start sacrificing them selves than to get to power head.AS I stated personal preferance. I ran al. for over 40 years, was very happy with it. Still have al back up. But I for one will not worry a momment that s.s. is going to damage my out drive quicker than al.