Decreasing fuel tank size, or highly accurate fuel gauge.

[BrianAlbury]

I Just bought a boat to add to a rental fleet, however the fuel tank is too large to keep full (23' with 125gal tank). If the tank is full with 6 people it barely gets on plane.
Im having a problem coming up with a solution, I either need to decrease the fuel tank size without physically removing it (it's deep in the fiberglass). Or I need an extremely accurate fuel gauge, of which I cannot seem find.

 

[jfm]

What make/type/model is the engine? If it is fed with fuel electronically you can read the fuel used by each customer off the canbus

 

[PCUK]

Fit a fuel computer.

 

[Divemaster1]

Rather than doing surgery on boat, can you fit trim-tabs (smart tabs) to generate that extra lift ??

 

[BrianAlbury]

Rather than doing surgery on boat, can you fit trim-tabs (smart tabs) to generate that extra lift ??

The boat already has trim tabs, but they are more for balancing it. I don't think they give it any real lift.

What make/type/model is the engine? If it is fed with fuel electronically you can read the fuel used by each customer off the canbus

It is a Yamaha HPDI 200hp. I am talking to a mechanic today so i will ask, but the concern would be if they put gas in themselves. So far I think a fuel flow/trip computer might be my only option however since for some reason no one makes an accurate fuel gauge.