Question about Water Pressure and Jackplate

[Jsc11700]

Mercury Verado 225hp Serial 1B311855
Ranger Z20 25p tempest plus
Smartcraft version 3.00

I hope this makes sense....what is the correct trim position to use when reading water pressure to determine if I am safe to raise the motor? I did some running around today and narrowed in my " sweet spot" in regards to best top end speed vs trim height. Per Smartcraft and gps readings: Trim position on Smartcraft 4.5 water pressure 25psi, 6000 rpm 68.9mph two full tanks of gas, slight chop, 65degrees air temp, 900 feet elevation.

Here is my confusion... As I trim past my "sweet spot" to max trim allowed by Smartcraft / Verado computer my water pressure falls to 19psi and my rpms increase to 6100 but my top end speed falls due to over trimming. Is my basis for water pressure determined by water pressure at the sweet spot or the water pressure at max trim?

[2500]

Hydro dynamics. You have found the sweet spot. Trim angle for me is by feel and jack plate by water psi. I ran go fast hulls for years and it's feels right when you feel it. Try to raise plate and stay at same trim angle. You have nose cone at correct level when you trim that 1 bump more you changed the blade bite and gear case cone angle thus slowing boat down and water flowing not smoothly over case gets less psi. However blade bite is also changed and RPM is more. Think of it as the blade screws thru water in a fluid motion the blade turns evenly and makes a revolution but change trim and the blades sorta start chopping or spins more.
I run about 70% trim when WOT. I have more but as you found the boat loses speed RPMs go up and water PSI drops. when I Ran Bullet I wouldn't even trim 50%.

[EuropeanAM]

Water pressure at your WOT "Sweet Spot" (which is what you've found) is what's important. You won't normally run at higher settings (as you're over-trimmed, creating excessive prop slip).

[Jsc11700]

Thanks! That's what I figured. Since my last posts earlier this year I have switched to a 25p tempest and experimented with load distribution and I am becoming more impressed with this Verado every time out.