best prop for speed

[dvandsm64]

we don't tube, ski,etc... we cruise and like to go fast. what would be best prop??

-mkm 5.7 liter L.h. motor 4200-4600 rpm according to plate on engine

-1997 celebrity 190 b.r. @3ooolbs.?

-1.62r alpha 1

-prop=19p wo95 414 48-58422a4

-lower= s-3-b-1 4281

-@63 mph. at 4600-1800rpm at wot.

thank you

 

[steelespike]

Re: best prop for speed

I can't be too specific.
I would say 63 is pretty good.Is your prop
stainless?It appears your saying your rpm is 4600-4800.
If its aluminum then a stainless may help you out
The real experts may be able to suggest something more specific.

 

[Bondo]

Re: best prop for speed

we don't tube, ski,etc... we cruise and like to go fast. what would be best prop??

-mkm 5.7 liter L.h. motor 4200-4600 rpm according to plate on engine

-1997 celebrity 190 b.r. @3ooolbs.?

-1.62r alpha 1
-prop=19p wo95 414 48-58422a4

-lower= s-3-b-1 4281

-@63 mph. at 4600-1800rpm at wot.

thank you

Ayuh,... a 19' boat with a 350 V8 should be a 1.50:1 outdrive,....

Is your 63mph at 4600rpms, or 4800rpms,..??

Is the motor 2bbl. carbed, or 4bbl. carbed,..??

 

[dvandsm64]

Re: best prop for speed

it is a 2 barrell. not sure if gears inside are what the housing says. i believe it varies between 4600 and 4800rpm.

thank you for your help

 

[45Auto]

Re: best prop for speed

Don't touch your boat. Lots of big companies will be willing to pay you millions for it! This is better than the free hydrogen from the alternator and the fuel line magnet deals!

63 MPH with a 19" pitch prop on a 1.62 outdrive at 4800 RPM is a NEGATIVE 18% prop slip! In other words, your boat is going 18% faster than the prop is turning .....

In other words, at least one of your numbers is wrong.

Is your speed from your speedometer or a GPS?

5% prop slip (which is still almost unobtainable without dual props) would give you 51 MPH. Zero prop slip would give you 53 MPH.

 

[dvandsm64]

Re: best prop for speed

thank you so much.

speed is from someone who drove it before we bought it. we just got speedo repaired and have as yet not driven it.

as i said gears could be different from what the case says. this comes from the marina mechanic who did some work on the boat.

the prop is aluminum.

it's a 2 barrell carb.

 

[45Auto]

Re: best prop for speed

Even using 1.5 gears in your boat (most common with a V8) shows negative 9% slip at the conditions you describe. A realistic number would be a positive 10% slip. With a 19" prop at 4800 RPM, that gives a top speed of 52 MPH with 1.5 gears or 48 MPH with 1.62 gears.

To evaluate any benefit you might gain from changing props on your boat, you need to know the true speed (use a GPS) and actual WOT RPM that the boat delivers with the current prop.

Without knowing those, you're wasting your time (and money) even thinking about changing props.

 

[nitrosteve]

Re: best prop for speed

I recommend breaking the repaired speedo and just believe your doing 63mph. Then you wont have to worry about a prop. I would say your realistically doing 45-50 depending on the load. Since your good on your RPM I would leave well enough alone.

 

[dvandsm64]

Re: best prop for speed

nitrosteve,

i guess your answere would be the best for us. though i have seen other boats with 5.7 liter advertize 60 plus mph? i assumed ours could do the same.

thank you

 

[metriccrescentwrench]

Re: best prop for speed

nitrosteve,

i guess your answere would be the best for us. though i have seen other boats with 5.7 liter advertize 60 plus mph? i assumed ours could do the same.

A buddy of mine has a 350 with a 4 barrel carb in a bow-rider that weighs around 3000 pounds so I'm guessing it's at least somewhat similar to your setup. He's played with several different props and the best speed he's seen is 50 mph on his gps. I won't say that a different prop won't get you a bit more speed, but from what I've seen there's not a ton of difference between props (at least once you get in the ballpark on pitch - and it sounds like you're there) unless you've got a performance hull like a Checkmate or similar.

 

[heathk2003]

Re: best prop for speed

I would try an enertia 20 pitch prop to try to get the most speed. I have a 19 foot boat with a 270 hp v8 and 1.6 lower unit and run 57 -58.5 mph gps at 5100 rpm with a 21 pitch enertia. Very happy with the prop on my boat which should be very similar weight as yours. I got mine off ebay for $439 with hub kit.