need help on selecting prop size

[DanielSprings G3]

ok i have a 2004 G3 eagle pro 165 with a 2004 yahama 25hp four stroke with 9 7/8 x 9 prop. with that prop with me and my buddy weighing 500 pounds plus gear fuel and two batterys it will push us 20mph @ 5400rpm with no water in live well. with water in live well it want get out of its way. so i put a whale tail on it would run the same mabe a little slower with out or with water not much of a change. So i bought a new prop 9.9 x 12 with me in it @ 5400 rpm i got 24mph. with water in live well about 21mph put budd in boat would not get over 13mph. so my question is what do i need to do to get a good performence out of this boat i know nothing about selecting props.

 

[steelespike]

Re: need help on selecting prop size

With 25hp your seriously under powered.
It appears a pro165 welded is about 960lbs your total is about 1800 lbs.
A G3 with 1479lbs total weight makes 23 at 6000 with a 10 1/2" pitch.
Your 12" prop was the wrong way. A 4 blade prop in a 8" pitch "might" help you out.
If its a portable gas tank maybe you could carry only 3 gallons Motor will use about 2.5 gallons per hour at wide open throttle.
balance is important if batteries are in the stern try moving to the middle or bow.Move the gas forward.Trim motor in with a load.(prop closer to the boat)Eliminate as much weight as possible.A few pounds in the wrong place could be the difference between planing and not.
It appears that a 8" may not be available but there is a 9" 4 blade ss that should help.