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SD 187 Volvo 4.3L - Prop questions

gmtk Member Posts: 15 ✭✭
I'm the new owner of a 2004 SD 187.  So far I love it.  First deck boat I've ever owned.  My only issue with the boat is the performance.  It porpoises very bad and the boat has to be trimmed down at all times. I've already installed a hydrofoil and trim tabs have been ordered.  I feel like the prop is wrong. It's the stock prop - 14.5 inch; 19 pitch; 3 blade.

I do NOT have a prop guy where I live (south Texas).  I'm just looking for a good cruising prop; kids are too small to tube/ski at this point.  Top speed on GPS is 40 mph WOT 4400-4800 rpms.

Any thoughts and help on this is appreciated.


  • cjjjdeck
    cjjjdeck Member, Moderator Posts: 1,872 ✭✭✭✭
    Welcome to the Owners Forum!

    Usually, you want you prop to have the ability to allow your engine to achieve wide open throttle (WOT).  It looks like that would be 4,800 RPM.  If your boat achieves that, then you have a correct pitch for all around boating.  If you were unhappy with let's say, hole shot for water toys, then you might want to change out your current prop to give you better performance for that activity.

    As far as trim verses porpoising goes, there a a number of factors.  Weight distribution is probably the first thing to look at, especially with where you store gear and passengers while under way.  Try to balance out the load best you can.  I will tell you, I often have my drive trimmed mostly close to all the way down, especially when there is a decent amount of wave activity on the lake.
    2012 SD237 I/O Mercruiser 5.0L MPI ECT/ Bravo 3
    2012 Load Rite Elite Tandem axle trailer