stingray 198lx prop size

roffey

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I am going to get a new prop form my boat, old one is bent and aluminum. My boat is 20 feet with a alpha one drive and a 4.3 TKS 190 hp motor. I currently have a 23 inch prop and tach 4900 WOT by the tachometer in the boat . I am playing with the idea of a 25 inch prop. I have a spare 19 for water sports. Do you people thing my boat and motor will handle a 25 inch blade?
 

QBhoy

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On the figures given, it should.
I think at 4900rpm, you are over the recommended rev range anyway. Does it feel and sound like 4900 rpm ? I.e. You reckon the tacho is accurate ?
What's the gear ratio on the drive ?
If your current 23"p is aluminium, I would be tempted to try a 23"p stainless. That will drop the rpm slightly and give a decent show.
If it is already stainless, might try a 25"p, but you may drop out the rpm power curve and loose performance and usability.
I'm not sure I have heard of many, if any set ups like that with a 25"p.
Cheers
Allan
 

QBhoy

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Just realised you said it was aluminium and bent.
Depending on how it's bent, that may be the reason you are getting up to 4900rpm. You might find with a new 23"p, the rpm may drop and performance improve.
This being the case, I would defo try a stainless 23"p.
All boats are different as they say, but my boat is kind of similar and runs really well with a newer model Laser 2 on it. Lifts the boat high out the water and runs so well, compared to a standard black max Aluminium of the same pitch.
 

roffey

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Just realised you said it was aluminium and bent.
Depending on how it's bent, that may be the reason you are getting up to 4900rpm. You might find with a new 23"p, the rpm may drop and performance improve.
This being the case, I would defo try a stainless 23"p.
All boats are different as they say, but my boat is kind of similar and runs really well with a newer model Laser 2 on it. Lifts the boat high out the water and runs so well, compared to a standard black max Aluminium of the same pitch.

Thanks for the response, my gear ratio is 1.62. I think I just may go with the 23p stainless as they are fairly expensive and I don't want to order the wrong one. As far as how it sounds at WOT, I don't think its over reeving so the tach may or most likely is out.

To bad you can't try a prop before you buy.. Hmm might be a good business for some one to start. Get a bunch of props and go to a busy lake or dock and open the doors, try before you buy...
 

QBhoy

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I think the 23"p would be ideal for it. Certainly give you good top end anyway. 21"P might be more useable for an all rounder ?
Some shops will let you try it out before you buy, but perhaps not all. Worth asking.
What kind of speed you managing with the bent 23"p and those revs ? Probably be quite a quick boat with a decent stainless !
It's probably not ideal for all sports boats and I keep read about people slating it, but I can't recommend the laser 2 highly enough.
 

roffey

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When the boat was new, two years back, lol. I was getting about 54. My bay is very muddy and the water level drops considerably in the fall. So after two years of the prop digging in mud it has bent. Now I can do 52 in glass calm with no wind, 54 with a little ripple and the wind at my back, lol. I could get the prop fixed but I'm using this as an excuse to get a stainless prop. I have a 19p as backup but its goes does make the boat rev a little high.

As you said it is a quick boat, sort of a sleeper, 20 foot bowrider with 4 or 5 and I can still top 50 mph and that was not the big motor for that model. I could have got a 4.3 MPI with 225hp, love it.
 

Scott Danforth

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have you verified the RPM with a diagnostic tach (not the dash gauge)?

going from a 23P to 25p may be a bit much, however the stingray is a light hull

my suggestion would be a proper 23P stainless as it will not flex as much as your aluminum does giving you a bit more top end, and lowering your WOT RPM a bit, however if your digging in the mud with your outdrive, I would recommend against stainless. I would recommend against digging in the mud period as the mud is also being pumped into your motor and filling up the water jacket.
 

roffey

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I hear what you saying Scott but at the end of the year I have no choice but to motor in the mud. There are two places I run into a little muck on the way out to the big part of the lake. For the most part of the year I have lots of water under my boat at dock, 6 to 7 feet. The last part of the year the "authorities" drop the water level by as much as 6 feet.

I have not verified the tach and suspect it is out. To be on the safe side I'm going to stick with the 23p as new stainless props are expensive and with the 23p I can travel in excess of 50 mph (GPS). Top end is not everything but it is fun, as I said the boat is a bit of a sleeper and I have had a few goes with jet skies and other go fast boats. I am just a big kid at heart
 

roffey

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oh... and I do have backup aluminum 19p and 23p if this is a complete waist of cash....
 
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QBhoy

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Looks like a serious prop. My gut felling tells me it wouldn't be of much use to you though.
 

jkust

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Stingrays are never sleepers, they are purpose built for speed. They were getting a legit 60mph out of the carbed v6 off the showroom floor a long time ago. When I see one on our lake, I put the hammer down and see what they can do because they are always game. I'm like you...still love the speed even having crossed over 40. Haven't found a boat that can take me down on my waverunner though there is one Ranger that comes very close.
Seriously though, I would think that a 25 is just going to be a dog out of the hole.
 

roffey

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Thanks to both of you... I really want the prop but I am afraid it will only get on plane with me and take most of the lake to get there. I think guys you talked me out of it, ill get the 23p stainless and wait till I see jkust on the lake and blow my hone as I blow by, lol.

The best I've done was 54.5 on the gps. So Jkust your safe for now... till I put the 4 BB carb on...
 
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Scott Danforth

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not sure about the canadian marinas, however many here in the US allow you to try props.

neither of you are safe once I get the motor completed in my build....bwahahaha
 

Scott Danforth

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just follow the link in my sig. building a 468 at about 490-500hp for the Rogue any more power and I need to upgrade the drive
 

jkust

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Thanks to both of you... I really want the prop but I am afraid it will only get on plane with me and take most of the lake to get there. I think guys you talked me out of it, ill get the 23p stainless and wait till I see jkust on the lake and blow my hone as I blow by, lol.

The best I've done was 54.5 on the gps. So Jkust your safe for now... till I put the 4 BB carb on...

Ha ha...my boat is a sleeper actually....Have blown past many a boat this past year since buying it and had them motor up to me later to ask what the story is. The small block 350 MPI gets up and goes pretty good even with a 17 on it. Most people seem to settle for the 5.0MPI and don't opt for the bigger one though of course all the Mercruisers are now obsolete with the new batch that has been out.

If I recall, the review of the Carbed Stingrays that they were getting 60mph out of had I think 23 SS Laser props on them.
 

QBhoy

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That Trophy propeller would be tempting. Some performance over the rest on that boat !! Incredible speed from a 4.3 and under full test conditions too !!!
 
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