mmwalters

If your propshafts taper where the enter the gearcase and the props use a thrust washer you have the small 1'' propshafts. If they are straight with no taper and use no thrust washer they are the fat 1 1/4'' shafts.
Removing the motor bracket would make a huge change. Whatever props you pick I think a tunnel tab or less setback will be what you need. Less setback will help the boat fly more level in rough water.

tj309

"Removing the motor brackets would be a huge change". Please elaborate on this.

Payton

AT is Active Thunder. Now called Chief.
If you go to the owners forums, I am sure you'll find a phone #.
I am sure the will help you.

throttleup

I'd agree with mmwalters, a good all-round prop would be the Hydromotive 4 blade Quad IV's. For optimum performance they need a little work for your application but should give you a top end within a couple mph of the 3 blade cleavers while giving you a better mid range speed as well as lower plane speeds and plane-off much better than your current props.

5 blade props are an option as well but they are about twice the price of the 4 blade props.

If you have any questions don't hesitate to call.

Matt
Throttle Up Propellers
727 531 2255

tj309

The shafts are 1 1/4" with no taper and no thrust washer.
TJ

mmwalters

What I mean is when you move 1000lbs of motors 12'' ,that will have a dramatic effect on the balance of your boat. Not a bad thing in your case as I believe 12'' set back with 2 500lb motors on a 25' hull is most likey way to much. You cat should plane much quicker and ride better and hold plane at slower speeds with no set back. You can always add set back at a later time if experience show you need it. If I were you I would pull the brackets, check with Matt on props and get your wife back on the boat

mmwalters

TJ just a thought As a stop gsp measure you could try placing some ballest in the nose of your boat. Lead shot from the gun store or sand bags would be worth a try. Make sure you wrap them up good so you don't have a mess in your boat. Maybe try 100-150lbs as far foward as you can place them. This will not help your props hook up but might keep the nose down enough so your wife will not be scared.

tj309

Thank you mmwalters and the rest of the members of this forum for the excellent advice. I am going to pull the 12" brackets and retain the 5.5" setback of the lift jacks. I am going to obtain a pair of 30" (good move from 32 cleavers?) 4 blade thru hub exhaust props.

Now a couple of more questions - how low should the motors be mounted? The jacks give me 6" of lift.

What is the purpose of large amounts of setback?

My closest marina is of medium size and the hottest thing they have done is a 300hp on a 21' bass boat. Are they competent to remove the setback brackets and properly mount the motors?

Lastly I was considering extra weight in the bow but thought it would be too stupid to mention. I will do the re-prop and setback removal 1st and then consider weighting the bow.

Again thanks for the GREAT advice.....TJ

Steve Zuckerman

tj,
24' is pretty short for twin 300 Mercs, then add in batteries and fuel, etc, and you are too tail heavy. Your boat is, like a lot of tunnels rigged for top end. Nothing wrong with that except your holeshot.
I drag raced U/O (600+ HP 2.5 Merc on a 17.5 Mirage Quartermaster) and we were always looking for a hard flat launch. We did several things to help holeshots, some of which will definitely help you.
#1 I highly recommend a ride plate under your jackplates. This simply fills in "the bottom of the box" which creates transom lift (I'll try to post some pics).
#2 The Hydromotive P5-X will launch your boat like a rocket. I have a holeshot problem on my 28 Nordic because of the high x dimension 19.25", and the P5-X (from Matt) rips my boat onto plane.
#3 As much as I dislike the look of them, "whaletales", properly designed, help tremendously. This basically turns your cavitation plates into tabs by adding surface area.
#4 I agree with mmwalters that you need some weight in the bow, to offset all that hardware hanging on the transom. You can experiment with duct tape wrapped shot bags of various weights. If you want to do this high tech, go with a water ballast tank. You can fill the tank at idle, which will give you a flat holeshot and porpoise free midrange, and then dump the water when you want to scream.
#5 A tunnel tab will work too, but make sure you have it trimmed up beyond horizontal in rough water. Your boat is relatively short, and all short(er) boats have greater tendency to stuff in rough water.
Hope this helps.
Steve

Steve Zuckerman

tj,
Here's a pic of a ride plate, which is the fixed tab attached to the hull and jackplate, and the whale tale which is attached to the cavitation plate. I would start with the whale tale, as it's easily sourced, inexpensive, and easy to install.
Regards,
Steve