What's the best prop size? - 22 ft tahoe 228 Merc Alpha One Gen II 220 HP

[ocdznutz]

I got this boat with a 14.5" , 19 pitch. Hit some rocks today trailering it. Damage isn't too bad, but I'll probably end up getting a new one. Met a guy today who says stainless is the way to go, but I replaced it once already with aluminum because it's cheaper.
1. What is better aluminum or stainless
2. Is this the right size? When I look at the back of the boat I feel like it's the statue of David with a teeny tiny little prop.
SN on the engine is 1A080231
Lower unit transom SN is 1A150158

 

[brodmann]

If you can supply RPM's and MPH at full speed, we can tell you if you're under/over propped. Basically you want to operate within the manufacturers recommended RPM range without exceeding it. That keeps the motor "happy". I run an aluminum prop most of the time because rocks aren't a hazzard where I run down here in Savannah, GA. The aluminum is lighter and is able to spin faster. My aluminum prop is a 17 pitch. I also have a stainless prop that came with the boat. I keep it in the boat as a spare. It's a 19 pitch. It produces a higher top end speed, but is very slow to reach plane. My Yamaha 115 has a recommended RPM range of 4500-5500. With my aluminum 17 pitch prop, I'm usually cruising around 3500-4000 RPM, but it will reach 5200 at full speed. My 19 pitch stailness prop Will only get me up to just within that RPM range of 4500. I'm "over-propped" with the stainless prop which is not good because it means the motor is working too hard to turn that prop. It's very heavy and has too much pitch. BTW the pitch of a prop is the distance it should travel in one revolution in inches. Hope this helps. The 14.5" diameter of the prop is basically dictated by the lower unit and the size of the prop that the lower unit is designed for. Basically the largest prop that will fit without hitting any part of the lower unit itelf.

 

[ocdznutz]

How do you tell the manufacturers range? Bought the boat used so no manual. Do I go by the boat brand or the engine? I’ll have to try and check the mph/RPM next time I take it out. Right now I’m not sure I trust the RPM guage because it occasionally goes all over the place. I think I need to get a full electrical eval but that’s another story.

 

[QBhoy]

If you can supply RPM's and MPH at full speed, we can tell you if you're under/over propped. Basically you want to operate within the manufacturers recommended RPM range without exceeding it. That keeps the motor "happy". I run an aluminum prop most of the time because rocks aren't a hazzard where I run down here in Savannah, GA. The aluminum is lighter and is able to spin faster. My aluminum prop is a 17 pitch. I also have a stainless prop that came with the boat. I keep it in the boat as a spare. It's a 19 pitch. It produces a higher top end speed, but is very slow to reach plane. My Yamaha 115 has a recommended RPM range of 4500-5500. With my aluminum 17 pitch prop, I'm usually cruising around 3500-4000 RPM, but it will reach 5200 at full speed. My 19 pitch stailness prop Will only get me up to just within that RPM range of 4500. I'm "over-propped" with the stainless prop which is not good because it means the motor is working too hard to turn that prop. It's very heavy and has too much pitch. BTW the pitch of a prop is the distance it should travel in one revolution in inches. Hope this helps. The 14.5" diameter of the prop is basically dictated by the lower unit and the size of the prop that the lower unit is designed for. Basically the largest prop that will fit without hitting any part of the lower unit itelf.

Good info there. I might just add (if you don’t mind)…that I’ve always been amazed at how well the ally k series white props perform. I’ve often known them to outperform some like for like pitch stainless props. Just such a good prop. Quite a fair bit of performance oriented design, cut and shape about them. Not terribly too far off being almost cleaver like even.
I also once quite humorously remember a friend getting so excited about the performance gains to be had, when waiting delivery of his new stainless prop, which was to replace the white Yamaha prop that was on his 115. The prop which was fitted did terribly well. Unbelievably well even. Producing 40 mph gps on his fairly heavy 19ft hard topped Scandinavian all weather boat. Powered by a usually moderate behaving 115 4 stroke.
The new generic brand stainless prop came and was fitted (same pitch). She dropped nearly 4mph instantly. More again in less favourable conditions. When head scratching began, the old prop and new were compared on the table. Upon picking the old prop up. It seemed a little heavier than I might expect. It was that day, we both learned that Yamaha made a stainless version of the k series (not sure of the name, but identical in shape) and for some reason, gave them a white painted finish. Explained it all

 

[Scott06]

How do you tell the manufacturers range? Bought the boat used so no manual. Do I go by the boat brand or the engine? I’ll have to try and check the mph/RPM next time I take it out. Right now I’m not sure I trust the RPM guage because it occasionally goes all over the place. I think I need to get a full electrical eval but that’s another story.

Would assume you either have the 5.0 carbed 220 hp V8 or the 4.3 MPI 220 hp V6.

Carbed max rpm at WOT is rated at 4400-4800

MPI I think goes 4600-5000

Both have rev limiters that will keep you from damaging the engine. You want to prop them such that you can get to 4800-5000 rpm or so.

Which prop is right? Start with finding out what your current WOT rpm is with an undamaged prop then you can go down in pitch for for higher rpm and more hole shot, up in pitch does the opposite. Probably what you have on there is pretty decent overall use prop, although with a 22 ft'er and 220 hp you might want lower pitch

Depending on what you want to do you can go SS or 4 blade, really depends on what you want out of your boat.

Which is better? AL is easier on the wallet and easier on the lower unit if you hit something , but will give up performance vs a SS

 

[ocdznutz]

Would assume you either have the 5.0 carbed 220 hp V8 or the 4.3 MPI 220 hp V6.

Carbed max rpm at WOT is rated at 4400-4800

MPI I think goes 4600-5000

Both have rev limiters that will keep you from damaging the engine. You want to prop them such that you can get to 4800-5000 rpm or so.

Which prop is right? Start with finding out what your current WOT rpm is with an undamaged prop then you can go down in pitch for for higher rpm and more hole shot, up in pitch does the opposite. Probably what you have on there is pretty decent overall use prop, although with a 22 ft'er and 220 hp you might want lower pitch

Depending on what you want to do you can go SS or 4 blade, really depends on what you want out of your boat.

Which is better? AL is easier on the wallet and easier on the lower unit if you hit something , but will give up performance vs a SS

Thanks! I found the WOT Rating on the Flame Arrester label, and you are spot on. I was thinking lower as well, since it take a bit to plane. There actually aren't too many rocks where I'm at in Central Florida, but trailering into a steep ramp perpendicular to a canal was a first for me and ended up just a wee bit too far back and now I have some light damage to it. Maybe I'll stick with an aluminum with lower pitch to see how that works before I make the switch.

 

[Scott06]

Thanks! I found the WOT Rating on the Flame Arrester label, and you are spot on. I was thinking lower as well, since it take a bit to plane. There actually aren't too many rocks where I'm at in Central Florida, but trailering into a steep ramp perpendicular to a canal was a first for me and ended up just a wee bit too far back and now I have some light damage to it. Maybe I'll stick with an aluminum with lower pitch to see how that works before I make the switch.

if relatively identical prop dropping 2" in pitch should raise your RPM 400 or so at WOT.

If you are new to swapping props that is another reason to stay with Aluminum. I cut my teeth trialing aluminum Michigan Wheel Vortex 4 blade props on my old boat, which was a small 17 ft Bowrider underpowered with a 3.0. It was an inexpensive way to try some things out and get some experience with different prop styles and pitches.

 

[Scott Danforth]

I ran a 15x19P Solas stainless on my SeaRay 190 with a 220hp 5.0 / A1G2 1.62:1. I would hit 4900 RPM with just me in the boat trimmed out and just shy of 50mph

if you hit rocks often, stay with aluminum as aluminum props fold when you hit things, stainless props can take out the lower unit when you hit things

the right size of the prop is the one that gets you to the upper half of the WOT RPM window

 

[QBhoy]

Hi. Probably prudent for me to throw in that the rpm range of the 4.3 mpi is actually 4400-4800. If that is what you have.
I can also say that having messed about with a few boats with this mpi 4.3. I know that it is absolutely crucial to have them propped to see right to the top of the rpm range…or dare I say it…just a little over. Somewhere just below the limiter is good. Reason being that they tend to be fairly sluggish down low in the rpms. Hope that helps.