Jcat2010
Well-known member
- Joined
- Sep 4, 2022
- Messages
- 217
- Fluid Motion Model
- R-27 (Outboard)
- Vessel Name
- Barchetta
Just for those who like to know how much fuel they "really" have, I have some info on the fuel tank in our little boats.
When the marina pump shuts off, we likely don't have 147 gallons on board. At best, with the ullage designed into the tank due to seasonal expansion, etc, we might have 138 gallons. And with a fuel suction tube about 1.5" off the bottom, there's about 5 gallons unusable slop in the bottom. Consider that an F300 really, really, really does not like to suck in any air in the fuel and there's maybe another 5 gallons. So, actual fuel you can safely use might be 128 gallons.
I've seen the same with other boats I've had. The tank capacity is what's in the documents, but if you drain them down manually, and fill them back up, it's never that number. Commonly there's 5 gallons left below the tube and there's 10% ullage. The Yamaha display starts flashing the last bar as a warning, but I've never gotten that close in real life, only in tests.
Do with this info as you see fit, but now I can determine how I want to do my fuel calcs.
When the marina pump shuts off, we likely don't have 147 gallons on board. At best, with the ullage designed into the tank due to seasonal expansion, etc, we might have 138 gallons. And with a fuel suction tube about 1.5" off the bottom, there's about 5 gallons unusable slop in the bottom. Consider that an F300 really, really, really does not like to suck in any air in the fuel and there's maybe another 5 gallons. So, actual fuel you can safely use might be 128 gallons.
I've seen the same with other boats I've had. The tank capacity is what's in the documents, but if you drain them down manually, and fill them back up, it's never that number. Commonly there's 5 gallons left below the tube and there's 10% ullage. The Yamaha display starts flashing the last bar as a warning, but I've never gotten that close in real life, only in tests.
Do with this info as you see fit, but now I can determine how I want to do my fuel calcs.
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