need advice switching props

[ironjam21]

hi, i have 19p aluminum prop on my 3.0 mercruiser/ 17' maxum. my rpms are way too high with this prop before i'm even at WOT. i'm looking to switch to SS, so should i stick with a 19p prop considering the added weight of SS or should move to a 21p? right now i'm running at 38 mph @ 5,000 rpms. so i'd also like to add a few mph to my top end and of course get my rpms down. i'd appreciate any help!

 

[WillyBWright]

Re: need advice switching props

I'd go up to a 20 or 21 in a stainless. The thinner blades slice through the water easier, and stainless props of the same pitch usually turn more engine RPMs than equivalent aluminums. The thinner blade is more of a factor than the added weight. Just stay away from the ventilated stainless props, or at least get one that has vent plugs available. Ventilated props don't do well on sterndrives.

Another option you might consider is an aluminum Alpha 4-blade in a 20 pitch. They're made specifically for sterndrives. Many of the stainless props that fit Alpha-sized gearcases are designed primarily for outboards.