Prop Question of the Week

[EricG]

Since we haven't had a prop question this week, I thought I'd take my turn. I currently run a 20 or 21 Pitch Cleaver (Quicksilver) on my stock 350 Magnum/alpha 1 (it originally was stamped 21, but it appears to have been stamped 20 over it). 4400 RPM at WOT, about 59/60 on the speedo. I don't see any of the prop manufacturers still selling Cleavers, which tells me that maybe it is old Tech. For a boat the size of mine (it's a '88 Z21), I'm not dissapoited with the top end, but with more than 1 person in the boat it has NO bottom end (8-10 seconds to plane).

What I'm wondering is what pitch in a "regular" style SS prop would you recommend trying to keep similar top end but possibly improving the bottom?

Any insights would be greatly appreciated. Thanks.

EG

[wintersux]

As Z owners we appear to be the ugly stepchildren of Donzi. Prop questions are always a subject which generate lots of opinions, but no one has any?
Even though I am a Z owner, I read this message board every day. There is a lot of good info.

[seano]

Eric...although not a Donzi owner, my opinion is that you can use a few more RPMs...I believe the WOT range on your motor is 4800 to 5100. you should try a 19" 3 blade wheel. not sure about which models fit the Alpha, but it appears that there's too much pitch there and that's why someone "depitched"(for lack of a better word) the prop to 20"...this will give you a better holeshot and more revs at the top---hope this helps, let us know how you do.

[DonziDave]

I use a 21 pitch cleaver on my 18 w/ a 350 Alpha 1. Remember that a cleaver is a surface running prop and should be trimmed with the top blade out. This gives me 4900-5000 rpm at best trim. I get a suprisingly great hole shot with this prop. Although I have run larger pitch props which give more top end, I like the 21 pitch because it has a lot of mid-range punch. It reacts very quickly to the throttle which is a lot of fun powering thru chop or just carving up the lake. Dave

[GeneD]

Eric, I am surprised that you still have that prop on your boat. Especially on an '88. Do you still use a straight edge razor too?
Sorry, only having a bit of Donzi fun with you.
Anyway, you need a Mirage.
The 4400 RPM's with the cleaver sounds low, and I'm not sure why. I suggest a 19 Mirage or Mirage Plus. Perhaps a Stilletto. The 5100 Max RPM on the Magnum suggested by Seano
seems a bit high. But for a Magnum, that might be right. I like to stay under 4900 RPM's. I think the 19 Mirage Plus would put you in a good Donzi state of mind, and give you the hole shot you want and the top end you desire.
I think you will be pleasantly surprised.
The cleaver just cavitates too much for our boats.
Z boats included. Wintersux...you are not the bastard step children! Not even adopted. Full fledged members of the family!

------------------
GeneD
007
Melbourne, Florida

[EricG]

Thank you all for the good info - I can't wait to start experimenting.

As far as being the step-children, I haven't gotten that feeling at all. I followed a yellow 22 and a blackhawk through the Lake Washington ship canal last weekend, and they were very quick to "honk and wave". There are so few of us out here, that we all have to stick together.

As an aside, the "Dragon Lady II" is named after my step-mother - so maybe I am the bastard step-child......

EG