Rinker 212 Prop Selection

ahlbe1clahlbe1cl Posts: 3Member
edited May 2016 in Engine Discussions
Hey Guys, First post on the forum.

I recently picked up a 1997 Rinker 212 Festiva (Cuddy)

The boat has the Mercruiser 5.7 with the Alpha One geared at 1.62. I thought 1.47 was the factory equipped, but at any rate, I have the 1.62. (Actually, I verified the serial numbers on the engine cover and all match.  This boat came with the 1.62 from the factory it appears)

The prop is currently a 15 1/4 x 21P. The hole shot is fine, but I can actually over rev the engine with the current setup.

The safe RPM range is 4200-4600, but I believe I've ran it as high as 5500 for a brief moment. This is not safe and I prefer not to do it again.

So I'm wondering what Prop you guys have used in this scenario.

In theory, if the boat came with a 1.47 and 21P prop, this would be more or less equivelant to a 1.62 with a 23P prop. Anyone have experience, or recommendations with this?

Thanks!
Post edited by ahlbe1cl on

Comments

  • floater212floater212 manhattan, il.Posts: 110Confirm Email, Member ✭✭
    I have a 2005 212 xr1 350 alpha with a 2.00 gear, I use a 19"x 14.5 s/s five blade from hill marine, we use our boat for towing tubes, skiing, kneeboarding and wakeboards and I love the hill 5 blade, great for everything I do. when we go out my boat is rated for 8 people and that's how many is in there and that prop will pull like only 1 is in the boat and get up around 48mph cruising. they are also better than mercruiser high fives and under $400... check them out Ron Hill Marina "pleasure props".
  • ahlbe1clahlbe1cl Posts: 3Member
    What RPM's are you running?  Your numbers don't seem right.  Based on the math, you should be running 5500+ RPMs
  • 212rowboat212rowboat Posts: 2,000Member ✭✭✭✭✭
    ahlbe1cl said:
    What RPM's are you running?  Your numbers don't seem right.  Based on the math, you should be running 5500+ RPMs
    your question seems legit on the surface, but the prop he's speaking about doesn't play by the well established rules where prop calculators are concerned. 

    the bend and blend of pitches is astounding on those things.  It may carry a rating of 19p, and that might be where it's pitched mid blade, but I wager the trailing edge on that prop is closer to 22p- and that is right before the cupping which is significant enough that it will almost hold a bead of water while the prop's shaft is parallel to the ground.. 

    It's my feeble mid making this up, I'll admit- but those five blades overlap at the leading edge... the ability to transition from one pitch to another so abruptly is caused, in my mind, with the leading edge of the blade just before disrupting the water tension before the following blade take a bite and pushes off of it, and in turn disrupting the water for the next blade.  I posted a pic of mine directly from the exhaust side of the hub, and another from a birds-eye view if you were looking at a drive mounted prop... the blades are really big and flower pedal shaped, and I really think there being five of them, and overlapping in such a way allows that transition to work... meaning the boat can push a higher pitched prop than it should be able to, but in this case, the prop can transition the pitch more dramatically.

    if you know what a cleaver prop looks like, where the blades bite into basically undisturbed water providing maximum bite, this is the opposite...

    it's a clever design... and I ain't parting with mine... though, I may have to, as it turns out... the new engine produces A LOT more power than the old one.  
  • ahlbe1clahlbe1cl Posts: 3Member
    Mystery solved tonight.  Motor and prop combo are fine.  Tach was reading wrong.  Apparently I was idling at 2000 rpms...not really.  I accelerated to what said 5000, but it felt much lower, then the tach corrected itself and read 3200.  From there I was able to run the motor up to 4600 rpms or so.  Life is good.
  • Michael TMichael T Posts: 5,974Member ✭✭✭✭✭
    ....when that happens life IS good, LOL!
Sign In or Register to comment.