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What limits the size of the prop?

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What limits the size of the prop?

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Old 08-10-2003 | 05:38 PM
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I am carrying minimal equipment. Nothng in the water but drive and tabs. Actually the more I think about it, I'm requiring alot of left tab to offset torque. Almost 3/4 on the throw on the left tab of the 280 K planes. Could this be causing so much drag that it would reduce my RPM to 4650? Doesn't seem like it would. . .
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Old 08-10-2003 | 06:47 PM
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Hey Kirk,

Where are you running the tabs on the indicators? Shouldnt need to be much past 5. If you are running much past 5 you are getting a lot of drag right there. The reason I didnt like the bravo props on that boat is the reason you are having to use add. port tab. Too much blade area for such a light and narrow beam boat. It manhandles the boat. I guess the diff. in salt to fresh is substantial. I actually like the hydromotive on that boat. It has plenty of natural bowrise, in salt anyway, to offset the nuetral lift of the hydros. Good luck.

Mark
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Old 08-10-2003 | 07:24 PM
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Mark, I'm running close to 8 on the left tab!! I agree that the Bravo has too much blade area. Why would Jo and others be running them successfully, yet I cannot? Too much torque/HP compared to what they are running? This all makes sense though. What do you think about a 25 or 27 Hydro? oR should I get an assortment of Mirage Plus props?

Thanks,

Kirk

Last edited by Elite Marine; 08-11-2003 at 08:27 PM.
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Old 08-12-2003 | 06:19 AM
  #44  
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More torque = more tendency to want to lean wiht the narrow beam boats. It is hard for me to say not knowing the handling diff. between salt and fresh, but you should not need to run that much tab. Where is the right tab set when the left is at eight? Is it eight when at cruising speed and above? If so when you are up to speed have you tried bringing them up and see if the boat stays balanced? Remember how snotty the water was the day I took you and Joe out on the test? I showed you the tabs set at about 5.5 on the indicators.
Try the 25 hydro if you can borrow one. I have a 23 I used to run on that boat I couls send you but it might bump your rev limiter depending on where it is set. Mostly I ran the assorted mirage +s, but you have to get past them blowing out. It takes some practice but after a while I did not have a problem with that. If you wanted to stay with a bravo I always wondered about putting a shorty lower on the boat. I thought that it would take away from some of the torque effect if the props was not as deep in the water. Keep me posted.

Regards, Mark
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Old 08-12-2003 | 06:26 AM
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5.75!!!wow...that's a big # for a 4 blade!...better look at bringing that up.
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Old 08-12-2003 | 09:55 AM
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So none of the props you've tried would turn more than 4800?
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Old 08-12-2003 | 09:56 AM
  #47  
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If you're running with the tab down that's your problem. Too much drag!! Run with both tabs all the way up. If needed put a some weight, (sand Bag) in the stern (on the right side) to help level the boat. And any movable weight, anchor, lines, fenders, cooler. Good Luck.
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Old 08-12-2003 | 10:09 AM
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"If you're running with the tab down that's your problem"....this is incorrect statement!...you need to find the ROOT CAUSE...then and only then correct that....not put band-aids on assumptions.

you need someone that can assess this thing as a system...look at the engine,,,the hull,,,drive,,,prop...
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Old 08-12-2003 | 11:02 AM
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Joey,
I was answering Kirk's question, "why can't I spin the prop?". The answer is to much drag!! He is running with his tab down.
The items causing him to run with the tab down needs to be corrected. Wrong prop, CG off, drive too low etc.. The boat needs to be set up.
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Old 08-12-2003 | 05:14 PM
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I agree that the boat need to be set up properly, but Mark , the previous owner had the boat handling fine with a 29P Mirage, as did I when I brought it home. I think he is correct about the torque on such a narrow beam. I'm looking to try a 25P or 27P Mirage plus this week and see what it does for me.

Nothing has changed since Mark owner the boat except for a little more HP/torque. The drive is the same and the boat balance is the same.

Maybe a shortie lower would help??

Last edited by Elite Marine; 08-12-2003 at 06:43 PM.
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