Measure air gap from lip of hatch.
Liquid Depth (inches)	Barrels	Gallons	Air Gap (inches)
0	0	0	44.5
7.5	1.71	72	37
10.5	2.89	121.23	34
13.5	4.06	170.46	31
16.5	5.23	219.69	28
19.5	6.4	268.92	25
22.5	7.58	318.15	22
25.5	8.75	367.38	19
28.5	9.92	416.61	16
31.5	11.09	465.84	13
34.5	12.26	515.07	10
37.5	13.44	564.3	7
40.5	14.61	613.53	4
41.5	15	630	3