Help with info on my current prop please

[tmh]

I bought my used boat last season and was told the aluminum prop was a 19" pitch. Today I finally got it out of storage and read the numbers inscribed on it. 48-78120-19 . Looking around on google I see this is indeed a 19" pitch, and looks to be a 14" dia. and a 16 deg rake (found this on one site). It may be a "Black Max" but not sure.

Anyways, what I'd like to know is what characteristics this prop might have compared to others. My boat is 19', heavy deep V with a small block V-8 305 mercruiser engine 200hp. The boat is stern heavy I'd say, not sure if this prop helps or hurts this. I only got WOT rpms to about 4,000 last year, but I removed 100's of lbs of wet foam from he back half over the winter and also cleaned some growth off the hull, so we'll see this year.

Anyone know this prop and how it performs?

 

[WillyBWright]

Re: Help with info on my current prop please

It's an average prop for average use. They use it on outboards as well as sterndrives. Being an all-purpose prop, it does an all-purpose job. But a specialty prop for the particular boat type is very likely to get you better performance. There is a 4-blade Alpha prop designed specifically for butt-heavy boats that might do better for you. They come in 16", 18" and 20" pitches. See what the prop you have now does minus the extra poundage and marine growth. I'm betting the 18" or 20" would give a noticable improvement. Every boater should carry a spare prop. The 3-blade aluminum makes a great spare.

 

[tmh]

Re: Help with info on my current prop please

OK, thanks, willy. Yeah, I really need to get a base point with my current setup before I test other props. I also am adding smart tabs which will change performace as well. That's enough changes (improvemets I hope) that I really don't know where it will put me at WOT and out of the hole.

I also have a Piranha 4-blade 18P to try out. Actually, I have 18 and 16P blades for it. It will likely wind up either my regular prop or the spare, The one you mentioned (4-blade 18P) may also fit the bill. Or, I may spluge on a SS as main prop, likely a 4-blade as we do lots of water sports.