prop help

[jd_1598]

I have a 1988 Wellcraft 192 Classic, 4.3L 175hp with an rpm range of 4200-4600 OMC sterndrive with ratio of 1.68, 2400lbs 25 gallons fuel and is a 19ft length, beam is 77" the dead rise is 18? and is a cuddy cabin. When I bought it in 2005 it had a aluminum OMC prop #391202 21p that took a while to plane the boat was stern heavy the performance was ok at 5 seconds to plane and 20 seconds to top speed of 40 mph by GPS at 4600 rpm. I installed smart tabs and what a difference....planes fast now and is very stable/flat on turns,very good investment. It always seemed fat and sloppy when the winds/chop would pick up and slow down to 32-35mph. I looked into prop slip and noticed it was in the 26-30%, the boat had come with 2 broken 19p props and so I decide to try a 19p prop, thinking someone had over propped the boat. I looked on ebay and find an aluminum prop for a few bucks OMC 391201 I think. I tried the 19p prop and now the boat is noticely quicker out of the hole top speed is down to 38 at 4200rpm and a little bit better 16% on the prop slip.
Skiing, tubing and cruisen are on the agenda, probably always have 4-5 people on board at most times 2-3 sometimes. I would like to hear some suggestions on a new SS prop, I have been looking at the Turbo-1 21p or now after learning about prop slip maybe the 19p or the Stiletto Bay Pro II 20p.

thanks Jim

 

[junior1113]

Re: prop info

Re: prop info

if it were mine i'd put a turbo 4 blade 19 p. imho they are the best props out there and thats all i run. great hole shots. carry heavy loads way better in choppy conditions. not to mention great fuel eff. and slip numbers

 

[jd_1598]

Re: prop help

thanks junior,
That is why I was thinking about the Bay Pro II as it is a 4 bladed prop.

Jim

 

[hwsiii]

Re: prop help

Jim, I would appreciate it if you would take the boat out again and run some tests with both props, as the numbers don't match up to me. You have a 21" pitch prop running 4,600 RPM with a slip factor of 27% and yet you have a 19" prop running only 4,200 RPM with a slip factor of 16%, and they are both of the same make and model. I find that there is something not right about that, so I would appreciate you doing the test with the same load in the boat both times. I just need the WOT RPM and speed.
When you get this information, I will be glad to help you as much as I can.


H

 

[jd_1598]

Re: prop help

Will do .....I'll try this week and get back to you.

Jim

 

[hwsiii]

Re: prop help

JIm, that sounds great and when I get the numbers from you I will run them through the program and we will see what it says.


H