Prop questions

[Stay-N-Moist]

Current setup is a 2003 Caravelle 218 With a SS High Five 5 blade 21 pitch.
Boat weight is 3400lbs with 5.0MPI 260 HP alpha 1 drive. WOT 4400 to 4800
Im looking for alternate props mostly just a spare but not sure what is the best option. 3, 4, 5 blade, Stainless, Aluminum
Boat is mostly used for cruising and pulling tubers.
Reason for looking for alternate prop I Believe I have spun the Hub on the highfive press in hub

 

[Davetowz]

Pull the prop off and inspect. as for a spare, same as you usually run is probably best.

 

[jimmbo]

You say it is a 21", and the pics you show a 17" and one that can't be determined.
You can just mark the prop and hub with a Sharpie, then go an run it for a bit, then take the prop nut off and see if the mark has split.
If the prop is in good condition, just about any prop rebuilder will rehub it.
Now you mention you are thinking about a different prop? What do you want from the new prop?
Also what WOT rpm are getting with the current prop?
I would recheck your engines WOT range, 4400 - 4800 is a bit low for a 5 liter to get 260 hp. That RPM range was used for the 220(approx)hp carbed engine

 

[Stay-N-Moist]

You say it is a 21", and the pics you show a 17" and one that can't be determined.
You can just mark the prop and hub with a Sharpie, then go an run it for a bit, then take the prop nut off and see if the mark has split.
If the prop is in good condition, just about any prop rebuilder will rehub it.
Now you mention you are thinking about a different prop? What do you want from the new prop?
Also what WOT rpm are getting with the current prop?
I would recheck your engines WOT range, 4400 - 4800 is a bit low for a 5 liter to get 260 hp. That RPM range was used for the 220(approx)hp carbed engine

I see what u mean buy 17p and not 21p but on the side of the prop it is stamped 21.

Next time i get home i plan on doing the marker test. Thanks.

Second prop is mainly just a spare but would like to try something different. like a 4 blade. Still plane on doing mostly cruising and a little tubing.

All the Mercruiser 4.3/5.0 and 5.7 say WOT range is 4400 to 4800 rpm.

Mercruiser WOT RPM Chart

Wide open throttle RPM range chart for Mercruiser powered boats.

www.rubexprops.com

WOT on my boat lands about 4600rpm at 35mph to 37mph

Thanks for any help and comments/recommendation

forgot to mention that the person i bought the boat from was a slalom skier so I get why he had the highfive prop and the boat has fixed trim tabs as well.

 

[QBhoy]

I see what u mean buy 17p and not 21p but on the side of the prop it is stamped 21.

Next time i get home i plan on doing the marker test. Thanks.

Second prop is mainly just a spare but would like to try something different. like a 4 blade. Still plane on doing mostly cruising and a little tubing.

All the Mercruiser 4.3/5.0 and 5.7 say WOT range is 4400 to 4800 rpm.

Mercruiser WOT RPM Chart

Wide open throttle RPM range chart for Mercruiser powered boats.

www.rubexprops.com

WOT on my boat lands about 4600rpm at 35mph to 37mph

Thanks for any help and comments/recommendation

forgot to mention that the person i bought the boat from was a slalom skier so I get why he had the highfive prop and the boat has fixed trim tabs as well.

Hi. If you have a 5.0 mpi, the rpm range is without doubt 4600-5000 rpm.
What ratio do you have on the alpha outdrive ?
Looks like a 17” prop you have there. If it’s a high 5 you should normally have a flo torque hub kit. Is it perhaps the case that you might have the quicksilver or older version of that prop ? With a pressed hub ?
Anyway. With that mpi…you really want to be propping the boat to see at least 4700/4800 rpm. That’s where they make the most power. Anything less and they can be a little weak.
I’d also say that at only late 30’s…you are way down on performance for sure. Looks like you have the trim tabs down there too. I’d keep them well out the way and up. They cause serious drag and bow plough the hull. You should be seeing close to or about 50 mph, all being well and a good prop.

 

[velociraptorfarmer]

If you want a relatively inexpensive backup option, a Quicksilver Nemesis will be an aluminum 4 blade that has pretty good performance and will get you home in a pinch.

 

[Stay-N-Moist]

Hi. If you have a 5.0 mpi, the rpm range is without doubt 4600-5000 rpm.
What ratio do you have on the alpha outdrive ?
Looks like a 17” prop you have there. If it’s a high 5 you should normally have a flo torque hub kit. Is it perhaps the case that you might have the quicksilver or older version of that prop ? With a pressed hub ?
Anyway. With that mpi…you really want to be propping the boat to see at least 4700/4800 rpm. That’s where they make the most power. Anything less and they can be a little weak.
I’d also say that at only late 30’s…you are way down on performance for sure. Looks like you have the trim tabs down there too. I’d keep them well out the way and up. They cause serious drag and bow plough the hull. You should be seeing close to or about 50 mph, all being well and a good prop.

Update
Got home this weekend. Performed a thrust test on the Highfive (Also yes you are correct that is a 13.5 x 17p with a press in hub) prop. Confirmed that it is slipping but I was able to get up to full speed and rpm on slow increase of throttle. Maxed out at 39mph at 4500 rpm. The HighFive has been sent out for reconditioning and new hub. Also received a new aluminum 14x19p 4 blade Turningpoint. Went out for a ride and RPM maxed out at 2400 and could not plane out.

Not sure where to go on direction of the alternate/spare prop.
Some one did recommend the quicksilver nemesis 4 blade 14x19.
Pretty sure ill end up with same results

 

[velociraptorfarmer]

Update
Got home this weekend. Performed a thrust test on the Highfive (Also yes you are correct that is a 13.5 x 17p with a press in hub) prop. Confirmed that it is slipping but I was able to get up to full speed and rpm on slow increase of throttle. Maxed out at 39mph at 4500 rpm. The HighFive has been sent out for reconditioning and new hub. Also received a new aluminum 14x19p 4 blade Turningpoint. Went out for a ride and RPM maxed out at 2400 and could not plane out.

Not sure where to go on direction of the alternate/spare prop.
Some one did recommend the quicksilver nemesis 4 blade 14x19.
Pretty sure ill end up with same results

Knowing that it's a 13.5x17, I'd try a 14x17 Nemesis. I've had Hustlers blow out behind heavy boats and fail to plane just like yours did. Once I threw on a Nemesis it made a world of difference. Not to mention Hustlers run about 2" big on pitch.

 

[Stay-N-Moist]

Knowing that it's a 13.5x17, I'd try a 14x17 Nemesis. I've had Hustlers blow out behind heavy boats and fail to plane just like yours did. Once I threw on a Nemesis it made a world of difference. Not to mention Hustlers run about 2" big on pitch.

Any opinions on a HighFive 13.5x21?
I have an opportunity to pick one up for cheep.

 

[velociraptorfarmer]

Any opinions on a HighFive 13.5x21?
I have an opportunity to pick one up for cheep.

If you're not even able to get a 17 pitch High Five up to your WOT RPM, a 21 pitch is only going to be worse. You need to get load off your engine, not add more.

 

[QBhoy]

Any opinions on a HighFive 13.5x21?
I have an opportunity to pick one up for cheep.

That’s not going to work if a 19 doesn’t. Have a wee look into the thinking behind prop pitches. There is a great write up at the sticky sections at top of the page. I think you’re in danger of going way off track here. You need to try a prop without a broken hub first off. Around 17” for starters. Your last 17” didn’t get into the rpm range (4600 minimum) by your last report, so you shouldn’t go more pitch for sure, you’d think.

 

[velociraptorfarmer]

That’s not going to work if a 19 doesn’t. Have a wee look into the thinking behind prop pitches. There is a great write up at the sticky sections at top of the page. I think you’re in danger of going way off track here. You need to try a prop without a broken hub first off. Around 17” for starters. Your last 17” didn’t get into the rpm range (4600 minimum) by your last report, so you shouldn’t go more pitch for sure, you’d think.

100% agreed.
Throw one of these on and see what it does: Quicksilver Nemesis 4-Blade Aluminum Propeller - For Mercury and MerCruiser Engines https://a.co/d/gYeaL2g