ski prop for 1994

[surfinagin]

To improve performance pulling skiers, my marina installed a Michigan Wheel Vortex prop (992204, 14X20, 4 blade) on my 1994 Searay 180 Bowrider Signature Edition.
Power: 5.0L Alpha One (190HP, Max RPM @W.O.T = 4,200-4,600 RPM)
Boat dry wt = 2,750lbs.
Primary use: Pull skiers/tubers, and some slow cruising. (max top speed not important).
The new prop hasn't been much better than the previous 3 blade prop, and can't find any specific ski prop recommendation other than "lower pitch is better for skiing".
Asking for recommendations for the optimum prop to maximize performance for skiing?
Thanks for your time.

 

[Stingrayaxe]

Your RPM results seem a little low. It should be more in the 4400 - 4800 RPM slot. Closer to 4800 would be best. Maybe try a 14X19. It should get up to a higher RPM and hopefully the results you are looking for.

 

[Lazy Daze]

There's a different direction you can head that will provide better results... Put a set of Smart Tabs on the boat. Huge improvement. If you're not familiar with them, search on this site and/or Google.

 

[surfinagin]

Your RPM results seem a little low. It should be more in the 4400 - 4800 RPM slot. Closer to 4800 would be best. Maybe try a 14X19. It should get up to a higher RPM and hopefully the results you are looking for.

Stingrayaxe-
Sorry I wasn't clear: The quoted Max RPM @W.O.T = 4,200-4,600 RPM is from the Owner's Manual.

 

[surfinagin]

There's a different direction you can head that will provide better results... Put a set of Smart Tabs on the boat. Huge improvement. If you're not familiar with them, search on this site and/or Google.

Thanks Lazy Daze-
The reason I'm looking specifically for a good ski prop recommendation is that my current prop got nicked up and needs to be replaced. Therefore I want to use this opportunity to find/install a better prop for skiing.
If the new prop doesn't provide acceptable performance for skiing, I'll definitely look into the recommended Smart Tabs!

 

[Lazy Daze]

Well, it's pretty straight forward... lower pitch is better for skiing

What was the original 3-blade prop pitch? Or... more specifically, what was the original prop supplied by Sea Ray (check the prop matrix on SR's site)? If your engine is healthy and able to achieve the top end of the RPM range with the standard prop, then drop about 3" and go with a 4-blade Merc prop. You could also look into a Hi-5 prop - but they get expensive and quite honestly, the tabs are still better.

A little boat with a V8 should be ripping out of the hole, even with the standard prop.

 

[surfinagin]

Lazy Daze-
Engine is healthy -boat has been maintained (only 420hrs on it). When I bought it in 2000, the original 48-78120-19 3-blade prop was the spare, a J14.25 X 21P was installed, and ran that until switched to the 4 blade 14X20 Michigan Wheel Vortex 8 years ago.
Reviewed the recommended 1994 Prop Matrix, but found no direct correlation for some reason(?).
The two closest results:
180BR 4.3L (155HP): 13.75X21 Max RPM 4,800
200BR 5.0L (190HP): 14X19 Max RPM 4,600 200BR 250lb > 180BR, 3deg lower Dead Rise, same engine/max RPM.
Can the above be interpreted to confirm the original prop on my 180BR 5.0L was 14X19?
Is there another prop reference that may provide recommended performance and ski props for my boat?
Thanks for your time!

 

[Lazy Daze]

Sometimes some data is missing on the prop matrix due to mid-model year changes. Try looking a year or two forward or backwards. Ideally, compare your drive ratio to what's listed so it's an apples to apples thing.

But, no, I wouldn't make an assumption based on other boats - better to find out for sure.

until switched to the 4 blade 14X20 Michigan Wheel Vortex 8 years ago.

You've had the 20" on for 8 years? In your first post it sounded like you just swapped it out.

A better way to figure out the correct "all around" prop (starting point) is to do a WOT run to find your max RPM. This should be done with a light load and keep trimming up as much as you can till it no longer makes a difference in speed or the prop starts to ventilate. That's important info to know anytime you're doing prop stuff.

Engine health... have you done a compression test recently? Just because it sounds good, doesn't mean each cylinder is firing properly. I'm not saying there is a problem - but it's a variable that should be eliminated. A comp test is very easy to do.

 

[Arminius]

My boat is 2' longer and the injected 5.0 is rated at 265 hp at prop. For skiing, the hole shot is critical. My "High Five" 19" is far superior to the three blade which also came with the boat. My engine is over-rev protected at 5100 rpm and the warning horn alerts me before I reach maximum trim and ventilation at WOT. I believe this is correct rather than tuning for a range. Torque times HP (times the constant) equals HP so get those revs up! Your engine or hull may have problems.

 

[surfinagin]

Thanks Lazy Daze-

From 1995 prop matrix:
180BR I/O 5.0L (190HP) Alpha One 1.65:1 ratio 14X19 prop 4,600RPM max

A J14.25 X 21P prop was on the boat when bought, which I ran until the 4 blade 14X20 (992204) installed in 2012.
The apparently original 48-78129-19 prop also came with the boat, though damaged.

Based on the standard 14X19 prop, appears the correct 4-blade prop is 14X18(?) The marina installed 14X20, therefore maybe that is the main problem here?

No compression test, but strongly believe the engine is fine. Same performance since bought 20yr ago.
May be a couple wks before I have an opportunity to run the boat to provide the RPM data.

Step One is to optimize the prop since need a new one, but the recommended Smart Tabs may follow since have always assumed the V8 weight delays getting the bow down and on plane pulling a skier out of the water. Not a great ski boat (big wake), but it's what we have and a 190HP V8 should easily get a skier out of the water.

Hope the additional info is enough for an expert to confirm that a 14X18 4-blade is the best option, or recommend a better alternative.
Thanks again for your time!

 

[Leardriver]

A 21 pitch is put on a lot of boats when new, in order to post a good top speed number for magazine reviews. I would rather have a 17 or 18 pitch prop to yank up slalom skiers, and manually keep the boat from revving too high. Top speed doesn't matter for watersports, 0-30 acceleration does.

 

[Lazy Daze]

OK, based on that info - yes, I think the 18" 4-blade will yield you some nice results. That will dig in nicely.

 

[surfinagin]

THANKS
Will shop for a 14X18 4-blade prop.
Any recommendations for brand/model or online suppliers appreciated!

 

[Arminius]

High Five! 17" or 18".

 

[surfinagin]

THX for your recommendation-
The Hi 5 is apparently "the best" @$700.
This boat is run <20hr/yr. Hope to get a 14X18 4-blade that improves perfomance for far less $!

 

[Arminius]

Have current prop repitched and a few holes drilled in it. Move 2nd battery to front of boat. Have everyone move to front of boat during hole shot. Put Viagra in gas. Use synthetic oil. Just believe! Paste large red button to dash and threaten to use it!
http://continuouswave.com/ubb/Forum4/HTML/004836.html#:~:text=Drilling the holes allows exhaust,power to plane the boat.

 

[Stingrayaxe]

I have been happy with my 4 blade Quick Silver Nemesis. Much less $$$ than the High Five. It's aluminum so more forgiving when the the bottom meets the prop. It will happen on some of the lakes we visit. Ouch

 

[Lazy Daze]

THANKS
Will shop for a 14X18 4-blade prop.
Any recommendations for brand/model or online suppliers appreciated!

Mercury/Quicksilver is well known throughout the industry as making very good props. I'm not downplaying others, but the Merc stuff is "known" good. It's not uncommon to see Merc props on other brands of engines.

 

[surfinagin]

Thanks for the Merc/Quicksilver prop recommendations.

My previous posted data from 1995 Sea Ray prop matrix:
180BR I/O 5.0L (190HP) Alpha One 1.65:1 ratio 14X19 prop 4,600RPM max

The QS Nemesis is in my price range, but requires going to a 17 pitch (2 steps down from the OEM 3-blade 14X19).
Would be less concern if mfr provided a "holeshot/ski" prop recommendation for this boat/engine, or if there's a trusted "Prop Selection Guide" that experts here endorse.

My boat is not nearby, therefore no time to experiment with various props and want to get this right the 1st time.
Based on comments so far, reasonably confident that going from 14X19 3-blade to a 14X18 4-blade is conservative and should improve holeshot performance with no high RPM or other issues.
Not as confident that dropping pitch to 14X17 for the QS Nemesis would present no problems.

Can I be confident that a 14X17 will work and present no high RPM or other issues?
Any other recommendations for a specific excellent prop to improve holeshots with a skier -based on experience with a similar boat?

THANKS for your time.

 

[Stingrayaxe]

I’ve gone back through this thread. Maybe I missed it but what is your top RPM results with your current prop on a lightly loaded boat with a half tank of gas? To really know how much pitch to go down when going from a 3 blade to four we need to know where you are starting. Top speed via GPS would also help. If I recall correctly it’s about a 200 rev rise for every inch of pitched dropped.