Originally Posted by alarmguy
Originally Posted by dja4260
I have a 1988 Wellcraft 180 Classic w/ Merc 3.0, Alpha 1.
My prop has no casting to indicate pitch. I'm fairly sure I'm propped wrong and want to see what others are using. Plus the prop that came with the boat is beat up.
3 blade, unknown pitch, 4600 RPM, 33 MPH, Cruising at 24 mph @ 3300 RPM.
Pitch/WOT RPM/ MPH, Cruising speed & RPM
Here is a suggestion keeping in mind we are talking different hull types and brands.
We have a new to us, barely used, mint, Chapparal 180 SSI with VolvoPenta 3.0 (same gm engine block as the merc) of course different outdrive.
However the prop was dinged up, been boating my whole life and played around with props for best all around performance.
I read up alot on the prop I am going to mention because of the following;
Chaparral, being a higher end respectable (as GW) manufacturer specifically mated this prop to the 180SSI with the 3.0 block and it came on everyone of their boats even though it cost more because they, being respectable, wanted the best performance out of the 3.0 engine.
After reading all this, I decided, for the first time, maybe in my life, to trust the manufacturer and I purchased a new OEM VolvoPenta 4 blade prop that Chaparral sold with this boat, in order to get the best performance out of the 3.0. Just the fact that Chaparral chose a more expensive 4 blade prop over a 3 impressed me.
Anyway, of course, we are talking two different hulls and styles of boats, just wanted to give you something to think about.
We are blown away with the performance of this prop, 4 adults on a 18 foot boat and it planes quickly will run up close to 4800 RPM @ 44MPH, which I think at that point maybe rev limited, FYI, we do not run full throttle, just testing it. Cruise around 3500 wish I could tell you speed, forgot, our lake is so big here that by middle of the day you can go much faster without banging around anyway.
Hope this helps some, but I think maybe back in 1988 boats were more heavy and a GW, lets face it is built like a tank. Our hull uses a lighter kelvar.
This is what we use, Im sure Merc had a branded one the same.
Volvo Penta SX Stern Drive New OEM Propeller 14x21 Prop 3587524 4 Blade RH 19spl
I cant tell you in words how impressed we are with the way the boat performs with this prop, had my bother and sis in law out with us, even he was shocked, boating his whole life to, we both owned boats anywhere from 18 feet to 29 feet for decades and he couldnt get over how well it ran loaded with 4 adults and gear with a 3.0, he thought it would be a dog and I was concerned as well but I couldnt turn my back on the deal when I saw this boat at the end of winter and why I bought it.
Boy I am glad I did, far exceeded what I expected from this engine.
BTW, first volvoPenta for me, every boat we owned previous was a merc or twin mercs
Thank you for the feedback. I found out my prop is a beat up 14x19 pitch. I'm glad to hear that you can pull a 21 pitch. My boat is heavier as Wellcraft makes good stuff and it's older. I grew up on a 23 ft Chaparral. It was a well built, quality boat!