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  propeller vents???

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Author Topic:   propeller vents???
humboldt jim posted 10-12-2001 01:46 PM ET (US)   Profile for humboldt jim   Send Email to humboldt jim  
Any of you Whalerite's own a 4 blade Offshore series stainless steel prop?? I do, on my 2001 225 Mercury Optimax (nice engine when it runs!).

I have had very good performance with my prop and egine. WOT 5500rpm/38knots. I have heard the vents, which are currently plugged, do not affect mid-range or top speed, rather just the hole shot. I would like to know if anyone has experimented with removing plugs before I start monkeying around with it. By the way it sits on the love of my life, my 1983 22 ft. Outrage.

Bigshot posted 10-12-2001 01:47 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Pull them and check it out. They also make smaller vent plugs.
Louie Kokinis posted 10-12-2001 02:39 PM ET (US)     Profile for Louie Kokinis    
Jim: Iím also swinging a 4 blade offshore on a 22. I toyed with the vents when I first got the prop, but decided to keep mine closed. The extra air will help if your running a really high pitch (for speed) or a really heavy boat Ė IMO our 22ís really donít need it.
lhg posted 10-15-2001 02:25 PM ET (US)     Profile for lhg    
I have done a lot of experimenting with the venting on Mercury performance props, which I use on both of my Whalers.

The main purpose of venting is, as mentioned, to increase the engine's power curve when accelerating to plane. If you need more hole shot, venting is the answer. If not, use the solid plugs. The nice thing about Mercury's new system is that there are three sizes of vent plugs, giving you the opportunity to achieve exactly what you need. If venting is desired, I would begin with the small size. I am using those on my 18 Outrage running Merc Laser II props, and they seem perfect.

On my 25 Outrage I am running Mercury's older fixed size vent Laser II props, and they do not have this "fine tuning" capability. They must be either plugged or run with very large venting holes. With this older style, the differences are very evident, I have discovered that plugging the holes allows for 400 lower rpm's at minimum planing speeds. I find this desireable, especially in heavy going in big seas or for slow planning situations (so that low powered 20' Revenges as seen on Cetacea page 20 can keep up with me!!!) So I run plugs in my 21" pitch "heavy load" props, but run the 23" pitch "light load" props open, where the extra "dig" supplied by the venting helps.

where2 posted 10-17-2001 01:10 PM ET (US)     Profile for where2  Send Email to where2     
Vent plug assortments are $5. Gas to run tests $10. Time in the boat having fun: Priceless. I like Bigshot's suggestion.

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