Dip Stick calibration

[Pascal]

I finally got a chance to calibrate a dip stick while fueling this morning.

I ve only done the fwd tank. Aft tank is almost empty but I need to clean it up before using. When the boat was on the hard I had both tanks pumped and cleaned but because the boat was blocked slightly now high there is still some junk in the back of the aft tank (access at the front)

Don’t know if the pic will be clear so the measurement for the front tank ( 53MY or 58YF) are as follows

10” from bottom 40 usg
12.75” = 80 USG
15.75” = 140 USG
18.75” = 200 USG
21.75” = 260 USG
24.5” = 315 USG full

Even when they work the mechanical gauges are pretty meaningless because of the shape of the tank. When reading half full, you only have about a quarter tank left or around 80. Not sure if in later boats hatteras installed better gauges.