Prop's performance & trim tabs - need help

[Bushwacker]

Bushwacker borrowed my mirage plus and charted real time real world #s vs the his Rev 4. He killed me in hole shot, min plane , time to plane , mpg, midrange , AND TOP END.

My 4B prop is a 14 1/8 x 20" pitch Michigan Apollo, not a Merc Rev. 4. I was not that impressed with the Mirage +; definitely not as good as the Apollo, especially regarding min planning speed, MPG, and top end, and that was with the vent plugs in. It was even worse with the plugs out. Only problem with the Apollo is it's a little too much prop for my rig - can only turn about 5250 with a moderate load, so I need about 2" less pitch. Will probably try a Powertech once I get some $ saved up. Will post Mirage + vs. Apollo numbers here when I get a chance.

Sandy - another reason my performance numbers look better is the DFI E-Tec vs. older carbed engine! The new DI engines don't dump raw fuel out the exhaust ports, which makes a big difference in MPG, especially at low speed! You're welcome to try my 4B Apollo over at Ft. Desoto. I'll be running my 4B 14x18 aluminum Michigan Vortex, as it'll turn ~ 5600 even with a very heavy load!

[Old'sCool]

Peter, My old boat ('90 22' Whaler OR) w/225 Yam. 2S and Bennett 120's. I went from the Yam. 19" 3Bl. to a Solas 17" 4Bl. I didn't have the weight issue you have. There was better holeshot, not quite the top end, but could stay on plane at a MUCH lower speed. That was my goal as that hull didn't ride too good fast in rougher water. I know all the "experts" will project what will be the end result but, if a local dealer worth their salt will let you try multiple props and document the changes/differences in return for a sale of two props is what you need.

[FELLOW-SHIP]

Hi Peter

You also talked about the Bennett tabs. There are a few guys that have switched to the 3” drop fins for the same problems you are having. We sell a little add on Kit to convert your standard 12” x 12” to a 12” x 12” drop fin. You would have to drill some holes in your tabs and bold the drop fin part onto your tabs. The part number is DF12 and you can order them from anywhere you get your marine hardware. They would be a Lot cheaper than replacing the whole Tab. If you would like to talk about it just call Bennett Marine and ask for Mack.


Fellow-Ship


Just for the Grins

[peterb]

Mack,

You have made my day. I have dual acuators on each tab so I would much rather buy the kit.

I will definately call you.

Also, everyone else, thanks for all of th 4 prop advice. Know I just havt to fiure out if I need 17" or 19" pitch 4 blades.

Peter

[gofastsandman]

Peter,
Merc has a prop selector program on their site. I`ve called Powertech and prop gods and they were very helpful too.

Denny,
You did tell me it was an Apollo not a Rev 4....... As for mpg , I only know it`s not pretty. I don`t have the temerity to do the math. Would Boysen reeds help? I`m spinning 5200 full fuel and light load w/ a 15 3/8 x 17p mirage +. `96 rude 150 w/ 90 #`s comp across the board. Oh, vent plate 1" up.

Fr Frank, thanks for the explanation, I think. It`s starting to make a little sense. I did say a little.
All the used powertechs I`ve seen 4 sale have been thrashed. The mirage + did marvelous work with the attitude , but as Denny said it does blow out. Lost a lot of positive trim ability, which is a concern in a head sea. So I will keep looking for a good 4 blade.
Thanks,
Sandy

[peterb]

Ok, here is where thing stand

First, I pulled the boat out of the Keansburg, NJ slip (to get it ready for the late fall bass run, plus tog fishing down at Barnegat Light).

Here is a snapshot of the Bennett tab setup. The tabs are 12" x 16" (the 12" tapes down to 10").

Question for Mack. Can I get the drop fin kit for these tabs? If so, what is the part number?

[image][/image]

[image][/image]


Second, I spoke with Altantis Props out of Mt Laurel, NJ. I gave them the appropriate boat and motor info (such as perf #'s with my current prop sets). They have some ideas that they want to bounce off of the Powertech guys (that's where I am leaning). They should get back to me early next week.

I will keeo you all updated.

Peter