Stainless or Aluminum Prop?

I am buying a 2018 Lund 1875 Impact with 150 HP Mercury XL 4 Stroke. The motor comes with the Mercury 14.5 Diameter, 19 pitch aluminum prop & considering upgrading to stainless steel. What are the pro’s & cons for each?

Thanks, LF

Stainless in my opinion gives you better bite. That said it’s unforgiving. If you fish rocky lakes or rivers with a bunch of rocks or downed tree’s alum might be your ticket. Otherwise, I’m pro stainless.

On a 150 hp a stainless prop will definitely make a difference in performance. An aluminum prop will run just fine but there will be flex in the blades. A stainless will hold it’s pitch no matter the speed. A good combo is a 19 pitch Tempest Plus.

What problem are you trying to solve with a different prop?

Getting the pitch, trim, and height right has a far greater impact than prop material.

As Dutch correctly points out, hit anything solid with a stainless prop, and you’re busting up lower unit parts. Personally, I’d rather bust a dozen alu props than tear up one lower unit or sterndrive. It depends on where you use the boat most.

Grouse

If you can afford it and want max performance, go stainless. Cost vs risk

All- Thanks for your replies & input. Good info.

Grouse- no problem, just trying to decide if I should replace the aluminum prop that comes with my new Lund 1875 Impact & 150HP Mercury. Very good point about replacing lower end vs. aluminum prop- Thanks

LF

There is no advantage to an aluminum prop. Your boat will ride better, plane faster, have better fuel economy and better overall performance with a stainless. Both props come with a plastic hub made to break instead of your lower unit parts. Any boat with a 150 or larger should come with a stainless prop.

I have a 19 pitch tempest and a 17 pitch rev 4 if you would like to try them out let me know.

MnPat1- I think that you and others have convinced me to go stainless. This was my feeling going in but wanted to hear from you all. I will be meeting with the dealer Tuesday and hope to talk them into supplying ss prop to finalize the deal. I agree with 150HP+ to supply stainless prop. Is 19 pitch Tempest correct for 1875 & 150 Merc 4 stroke?

Did not know both props come with plastic hub instead of tearing up lower unit- NICE!

Thanks- LF

I have both. If I’m going on a fishing trip to LOW or Lac Suel I put on the alum. If I’m at home on lakes I know I much prefer the SS. Although I did hit a rock in Lac Suel with an alum prop and still took out the lower unit to the tune of $3600.

I ran the 1875 Impact XS with a 150 and a 19 Tempest at 48MPH and 5550RPM’s. This was full fuel, 2 people, but a very light load outside of that. Once you get the boat loaded up you may be looking at a 17 Tempest or you could look into a 17 or maybe 18 Enertia.

These are pretty common props so maybe you can borrow a couple from a local dealer, and try them out before you bite the bullet on one. That’s always the best option when available.

I ran my boat (Yama 150) for 14 years with an aluminum prop. When I bought my boat I was very close to sea level, now, I fish at about 6,000′ elevation and have lost 20% – 25% of my horsepower. I was told going to a SS prop was my only hope of getting a little power back so this Fall I bought a SS prop. I won’t know until Spring if the improvement is noticeable in the seat of my pants when I hit the throttle. I paid $395 for the stainless.

Lakefront wrote:

MnPat1- Is 19 pitch Tempest correct for 1875 & 150 Merc 4 stroke?

A good shop will let you RPM test the prop and switch them out with you until you find the right one.

Hill hiker- Thanks for your info. I have a good dealer and I’m sure they will let me try or exchange ss props to find the best fit. LF

SuperDave- Hope your ss prop works out for you this spring. I’m sure my dealer will let me try ss props for the best fit.
Thanks- LF

My opinion is run stainless on anything 115HP and higher unless if you run in an area where you know you will be plowing the bottom or dealing with floating debris (river fishing). I believe that when you start dealing with more horsepower the aluminum will flex.

Your dealer should know what stainless prop fits your combination as that motor/boat combo is very popular.

Thanks Savage Brewer. Think I will keep the aluminum for shallow river fishing- buy stainless for lake fishing. LF

Having a spare prop along with nut and cotter pin with you is a great idea to be honest, so once you get the second prop I would leave it in the boat. Never know when something might happen and the spare prop means you can keep fishing and worry about it later…

Savage Brewer wrote:

Having a spare prop along with nut and cotter pin with you is a great idea to be honest, so once you get the second prop I would leave it in the boat. Never know when something might happen and the spare prop means you can keep fishing and worry about it later…

That’s what the kicker motor is for. Lol! Kidding aside, it would be physically impossible to replace a prop on the water. An extra prop in the truck or camp is definitely a good idea.

SuperDave1959 wrote:

it would be physically impossible to replace a prop on the water.

You obviously don’t like to get wet. It can be done… and easier while wearing a PFD.

Brian Klawitter wrote:

<div class=”d4p-bbt-quote-title”>SuperDave1959 wrote:</div>
it would be physically impossible to replace a prop on the water.

You obviously don’t like to get wet. It can be done… and easier while wearing a PFD.

Just don’t drop the spare prop, nut or cotter pin in the process haha

Interested in how you lock the blade to turn the nut? Just putting it in gear has never been enough in my experience.

Don’t have to make it back to the camp or truck, just shore is handy, at least shallows.

SuperDave1959 wrote:

Interested in how you lock the blade to turn the nut? Just putting it in gear has never been enough in my experience.

I personally keep a block of wood in the boat with my tools, but really anything you can jam between the prop blades and the cav plate will work. If you’re a Merc guy and you have a spare flo-torq hub in the boat the plastic piece works great as well!

hillhiker wrote:

<div class=”d4p-bbt-quote-title”>SuperDave1959 wrote:</div>
Interested in how you lock the blade to turn the nut? Just putting it in gear has never been enough in my experience.

I personally keep a block of wood in the boat with my tools, but really anything you can jam between the prop blades and the cav plate will work. If you’re a Merc guy and you have a spare flo-torq hub in the boat the plastic piece works great as well!

That’s exactly how I do it on land but couldn’t picture it in my mind out on the water.

All- Thanks for your responses. I have always kept an extra prop, pin, and wrench in my bass boat. Thankfully, have never had to use. Thanks again and fish’on.
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Why switch props? If I might ask. Is that motor not gonna be enough the way it comes? Serious question not being a smartass

Bearcat89 wrote:

Why switch props? If I might ask. Is that motor not gonna be enough the way it comes? Serious question not being a smartass

The main reason for switching props would be to get better all around performance out of your boat, including speed which is most of what people talk about when propping. Depending on the rig it can make a lot of difference on others not so much. With aluminum you can loose some pitch due to flex in the blade. This is why people often times say with larger engines you need to go to stainless. More power, more flex! Normally stainless will also allow for higher engine height and more trim angle as well. If squeezing every last MPH out of your boat is a big deal to you then stainless is the way to go.

This isn’t just the case with large HP engines though either. I’ve propped a lot of boats with 90 and 115’s that gain quite a bit of performance due to the extra trim you get before cavitating. I have even ran stainless on my 25HP and picked up a mile an hour.

Some of the gains are coming from changes in diameter, rake, cup, blade thickness, leading/trailing edge design, number of blades, and even the exhaust tube length. Props can have a lot more complicated designs when using stainless due to the extra strength. I think those items are often times a large factor in the gains, and people don’t even realize all that stuff is changing when making the switch. Propping is an interesting subject, and can completely change how the boat runs.

Bought the same boat in October and I got a stainless prop.

The key to propping a boat is based on your normal loading that you don’t over rev your motor at wide open throttle.

Most pleasure boaters load their boat about the same on every trip out.

A one inch change in pitch is about 200 rpm in WOT rpm.

Staying in a single prop dimension and changing style/cupping , material, or blade count can drastically change overall performance of your boat.

Without loading the boat and putting it in the water, it is impossible to know if
the “stock” prop in the right prop for you typical use.