Calling prop experts

[novicetech]

Hello, I have an imperial 17 ft boat with a 3.0, alpha one mercruiser, while running in the lake today, I hit something in the water and bent two of the blades. I would like to replace the prop and I am looking for some suggestions. The current prop is a quicksilser 48-78120-19, which will top out at about 5100 rpms with a typical load. I was thinking of ordering one of the hustler closeout props here on iboats and also moving up to a 21 pitch. But the hustler props claim to run with most stock stainless steel props and I dont want my wot to go much lower than 4800. What do you guys think?

 

[TilliamWe]

Re: Calling prop experts

Why not repair yours? But...<br /><br />What is the recommended WOT rpm of that engine? 5100 sounds too high! So the move to a 21p seems totally logical to me. It would reduce the rpms to about 4800

 

[achris]

Re: Calling prop experts

Rule of thumb for prop changes is a change of about 200prm per inch of pitch, so going to 21" would knock you back about 400rpm, to 4700rpm. <br /><br />I like your thinking with regard to WOT. With the really high quality fuel (not!) we are served up these days you are better off being slightly over rev, definitely not under revs. My 4.3LX is propped to 5000 also. Been that way for 11 years and has been one of the most reliable boats I know.<br /><br />One prop I would recommend you have a serious look at is the Quicksilver Aluminium 4 blade. They come in even sizes, 16, 18 and 20. I don'tknow what you're using the boat for, but I have found mine to be fantastic, I did lose about 3 knots off the top end, but the smoothness and weed free operation of this prop is well worth the tradeoff, for me. I also find it hangs in much better in really tight turns and when I go swell-jumping , the air in the blades doesn't send it into free-spin mode.<br /><br />If you move to the 20" you'll find that your WOT will drop about 200 rpm, still slightly above the Manufacurers WOT recommendation.<br /><br />Happy boating,<br /><br />Chris.........

 

[novicetech]

Re: Calling prop experts

bump!