Have 14x19 4 blade on 4.3 GXi. Upgrade to Stainless Steel worthwhile?

[FTP20]

Stingray 195X bowrider (2008 or could be an '07 or '09, can't recall) with a Volvo Penta 4.3 GXi-J and SX-A 1.66 outdrive. Turning Point Hustler 14 x 19 four blade aluminum prop with rubber hub. GPS-verified 48mph @ ~4800rpm at ~1500' ASL (speedo indicated 54mph). In reality we will never need to operate the boat over ~40mph. Fresh water use only in calm conditions.

The boat struggles to pull less skilled 150lb+ slalom skiers out of the water so I am wondering if upgrading to a premium stainless steel four blade prop, either rubber or solid hub, would provide a noticeable improvement?

Any suggestions would be appreciated.

The other wildcard is adjusting the Nauticus Smart Tabs SX, but that is a topic for a different area of this forum.

 

[alldodge]

Pulling skiers you need to get the RPM up fast. A 4 blade prop bits more so there is less slip, getting more slip out of the hole will help. Try a 3 blade 21 (same as 4 blade 19) because it will slip more on the hole.

If you want to flat pull someone up, try a 3 blade 19 and go easy pulling new skiers

 

[QBhoy]

I personally think that you can get away with most things, by propping with a good quality 3 blade stainless prop. But if it’s just for towing and pulling…there ain’t much a better prop for just that, than a high 5 prop. It’s just what they are designed for. Very very good at just doing this. But you will suffer on top end and mid range efficiency a little. I learned to wake board off the back of a maxum 1800 with only a 3.0. Using the high 5. Very very good for pulling. But they are a compromise other wise. A 19” one will usually show a little more rpms at the top end than a 19” 3 blade I’ve found. You’re limited will be around 4900/4950 on that gxi.
If it’s out and out speed and good all round…a tempest 3 blade will most likely be amazing on that fast hull of yours. I know a similar 1900 regal with similar gearing with a merc 4.3 mpi will do over 50 easily gps with a 19” one. Vastly improved acceleration too, compared to the 4 blade ally merc prop it came with of the same pitch.

 

[harringtondav]

Per QBhoy, hole shots and max WOT speed rarely happen together with a single prop, especially with a 4.3 on a 19' boat. I can't add much to the two recommendations above.
For reference my new boat shown in my sig has plenty of power for a 19.5' boat. I replaced the VP 3 blade 21P alum prop with a Solas Titan SS 14.25 22P. WOT reduced to the low end of the range, speed increased, and slip was hugely reduced. Hole shot remained very good. ...but I have plenty of hp.
My SWAG (scientific wild ass guess) is to go with a 3 blade SS. 19 for improved towing, or 21P for improved top speed, and probably better skier pull.

 

[QBhoy]

Per QBhoy, hole shots and max WOT speed rarely happen together with a single prop, especially with a 4.3 on a 19' boat. I can't add much to the two recommendations above.
For reference my new boat shown in my sig has plenty of power for a 19.5' boat. I replaced the VP 3 blade 21P alum prop with a Solas Titan SS 14.25 22P. WOT reduced to the low end of the range, speed increased, and slip was hugely reduced. Hole shot remained very good. ...but I have plenty of hp.
My SWAG (scientific wild ass guess) is to go with a 3 blade SS. 19 for improved towing, or 21P for improved top speed, and probably better skier pull.

Being nosey. Just had a look and pressed on your name there. Oh man…you’ve got the dream there. Is that your own boat lift by the water ? What a thing. If I was to move across the pond..I’d be after a similar set up. Lucky fella. What boat is that out of interest ? What does she have powering her. Looks lovely.
On your post there. Only thing I’d maybe pick up from it, is that I think a 21” would ruin the boat maybe. I messed about a fair bit with a few similar set ups with that engine. They really suffer with a lack of grunt down low if you run even the slightest increase in pitch. Very good up top, but if they are propped at anything but the very top of the rpms wot…they just really struggle to get going with anyone in the back seat. Was really surprised at how lazy they are down low. But powerful things when they get going. Can’t remember the exact details, but the last boat like it I messed with was a regal 1900 with the 4.3 mpi and a 1.6 ratio. Ended up with a 3 blade tempest 19” on it. I think it saw just under the limiter top end at maybe 4850 or close to 4900…and about 52 mph or there abouts. Maybe 53. Can’t remember. Great going for what it is. A 21” 4 blade was also tried (along with a few others). Was a small diameter merc ally prop. That actually hit the limiter or close to it and was about 47 mph or close. Was just terrible to get going though. Anyway. Bored you enough. Lovely set up you have there. Love to know what the boat is. Is she a chaparral?

 

[FTP20]

Thank you to everyone that has taken time to reply - lots of helpful ideas.

I should have clarified that my main goal is to improve the hole shot for getting slalom skiers out of the water and I don't care if the Vmax drops from 48mph down to the low 40s. I am always very attentive at the helm and can keep the engine under 5000rpm, regardless of prop.

Are these the two suggestions I should be considering?

Sites-WestMarine-Site

West Marine

www.westmarine.com

Worldwide Leader in Marine Propulsion

Mercury Marine is the world's leading manufacturer of recreational marine propulsion engines. Get sales, service and parts info, and find a local dealer near you.

www.mercurymarine.com

 

[alldodge]

3x19

 

[QBhoy]

Thank you to everyone that has taken time to reply - lots of helpful ideas.

I should have clarified that my main goal is to improve the hole shot for getting slalom skiers out of the water and I don't care if the Vmax drops from 48mph down to the low 40s. I am always very attentive at the helm and can keep the engine under 5000rpm, regardless of prop.

Are these the two suggestions I should be considering?

Sites-WestMarine-Site

West Marine

www.westmarine.com

Worldwide Leader in Marine Propulsion

Mercury Marine is the world's leading manufacturer of recreational marine propulsion engines. Get sales, service and parts info, and find a local dealer near you.

www.mercurymarine.com

If it’s pulling people up behind the boat. The high 5 mercury prop is the best of them all, by a long way. Designed specifically for it. I would never normally suggest anything but a 3 blade, but the exception to that is if you are specifically prioritising the main need for doing what you want to, more than anything else.

 

[FTP20]

If it’s pulling people up behind the boat. The high 5 mercury prop is the best of them all, by a long way. Designed specifically for it. I would never normally suggest anything but a 3 blade, but the exception to that is if you are specifically prioritising the main need for doing what you want to, more than anything else.

Does the the Marc High 5 come with different hub options or are they only solid for best performance?

Is there a formula or educated guess to determine how much the Merc High 5 will chop off the Vmax if the boat does 48mph @ 4800rpm with a Turning Point Hustler 14 x 19 four blade aluminum with rubber hub?

 

[QBhoy]

Does the the Marc High 5 come with different hub options or are they only solid for best performance?

Is there a formula or educated guess to determine how much the Merc High 5 will chop off the Vmax if the boat does 48mph @ 4800rpm with a Turning Point Hustler 14 x 19 four blade aluminum with rubber hub?

Yeah…it’s a interchangeable hub kit it uses. Will come standard with a flo torq hub kit in the box.
I think at a guess it might show very similar rpms to an ally 4 blade of the same pitch. Also think it might even not lose any speed compared to an ally 4 blade like that too. Chances are it might even gain some. But compared to a good merc stainless 3 blade the same pitch. It will usually gain rpm and lose speed for sure. Just that it’s not as efficient through the water at high speeds. But I suspect it might even show an improvement over a prop like you have now. Very smooth acceleration on them. I think you’ll find it noticeable. Have a look at them online and what they can do. No doubt about it. They are just superb for what you want.

 

[harringtondav]

Being nosey. Just had a look and pressed on your name there. Oh man…you’ve got the dream there. Is that your own boat lift by the water ? What a thing. If I was to move across the pond..I’d be after a similar set up. Lucky fella. What boat is that out of interest ? What does she have powering her. Looks lovely.
On your post there. Only thing I’d maybe pick up from it, is that I think a 21” would ruin the boat maybe. I messed about a fair bit with a few similar set ups with that engine. They really suffer with a lack of grunt down low if you run even the slightest increase in pitch. Very good up top, but if they are propped at anything but the very top of the rpms wot…they just really struggle to get going with anyone in the back seat. Was really surprised at how lazy they are down low. But powerful things when they get going. Can’t remember the exact details, but the last boat like it I messed with was a regal 1900 with the 4.3 mpi and a 1.6 ratio. Ended up with a 3 blade tempest 19” on it. I think it saw just under the limiter top end at maybe 4850 or close to 4900…and about 52 mph or there abouts. Maybe 53. Can’t remember. Great going for what it is. A 21” 4 blade was also tried (along with a few others). Was a small diameter merc ally prop. That actually hit the limiter or close to it and was about 47 mph or close. Was just terrible to get going though. Anyway. Bored you enough. Lovely set up you have there. Love to know what the boat is. Is she a chaparral?

2022 Regal 1900 ESX. Mine is likely the last produced. VP 4.3 250 hp. ...I got 10 free hp since the 240 hp I ordered was dropped. High pressure direct fuel injection, VVT, closed HX cooling. Plenty of power for a 3000# boat. I've been loyal Merc for 24 yrs, but their 4.5 didn't come close, and the VP is still GM.
I web trolled marine rail lift mfgrs. and reverse engineered mine from their web info. I built it 11 yrs ago. It is on the Mississippi river by Dubuque IA USA. 65' long providing 12' of lift. And I use every inch of it since this big river's level fluctuates a lot.
As far as my 21P recommendation, I was a bit reluctant about that since the OP's concern seemed to focus on low end vs high end. Lugging a 4.3 isn't a good idea.

 

[jimmbo]

Again a 19ft with a 4.3...
Ditching the 4 blade would be a good idea, a Prop that has adjustable Venting could help getting the engine to rev up to where it has more Torque to get the boat planing with a Skier behind, and dropping the Pitch to where the engine would be about 500-700 rpm above the recommended RPM, would also help.