Assumptions:
- Stressed diver SAC rate 1cf/min
- 1 min to sort out problem at depth
- 30ft/min assent rate from depth to 15fsw
- 3min Saftey stop at 15fsw
Example:
If at 132 feet one diver has a problem starts sharing air:
1 Min to sort out the problem
((132/32.8)+1)*1=5cf
3.9 Minutes to assend from 132fsw to 15fsw average depth 73.5fsw
((73.5/32.8)+1)*3.9=12.6cf
3 Min safety stop at 15fsw
((15/32.8)+1)*3=4.3cf
So one diver needs 5+12.6+4.3=21.9cf
So for two divers to do a safe assent from 132fsw would need 44cf
on a 3000psi 80cf tank the turn pressure would be 1600psi
2100psi if you add 500psi on top
Turn Pressure Chart
| Pressure (psi) Volume (ft3) |
| 2640 | 3000 | 3300 | 3442 |
fsw | ft3 | 80 | 95 | 104 | 108 | 120 | 77 | 80 | 100 | 80 | 100 | 120 | 130 |
30 | 14 | 462 | 389 | 355 | 342 | 308 | 545 | 578 | 462 | 602 | 482 | 402 | 371 |
40 | 16 | 528 | 445 | 406 | 391 | 352 | 623 | 660 | 528 | 688 | 551 | 459 | 424 |
50 | 18 | 594 | 500 | 457 | 440 | 396 | 701 | 742 | 594 | 774 | 620 | 516 | 477 |
60 | 21 | 693 | 584 | 533 | 513 | 462 | 818 | 866 | 693 | 904 | 723 | 602 | 556 |
70 | 23 | 759 | 639 | 584 | 562 | 506 | 896 | 949 | 759 | 990 | 792 | 660 | 609 |
80 | 26 | 858 | 723 | 660 | 636 | 572 | 1013 | 1072 | 858 | 1119 | 895 | 746 | 688 |
90 | 29 | 957 | 806 | 736 | 709 | 638 | 1130 | 1196 | 957 | 1248 | 998 | 832 | 768 |
100 | 32 | 1056 | 889 | 812 | 782 | 704 | 1247 | 1320 | 1056 | 1377 | 1101 | 918 | 847 |
110 | 36 | 1188 | 1000 | 914 | 880 | 792 | 1403 | 1485 | 1188 | 1549 | 1239 | 1033 | 953 |
120 | 39 | 1287 | 1084 | 990 | 953 | 858 | 1519 | 1609 | 1287 | 1678 | 1342 | 1119 | 1033 |
130 | 43 | 1419 | 1195 | 1092 | 1051 | 946 | 1675 | 1774 | 1419 | 1850 | 1480 | 1233 | 1139 |
140 | 47 | 1551 | 1306 | 1193 | 1149 | 1034 | 1831 | 1939 | 1551 | 2022 | 1618 | 1348 | 1244 |
150 | 52 | 1716 | 1445 | 1320 | 1271 | 1144 | 2026 | 2145 | 1716 | 2237 | 1790 | 1492 | 1377 |
160 | 56 | 1848 | 1556 | 1422 | 1369 | 1232 | 2182 | 2310 | 1848 | 2409 | 1928 | 1606 | 1483 |
170 | 61 | 2013 | 1695 | 1548 | 1491 | 1342 | 2377 | 2516 | 2013 | 2625 | 2100 | 1750 | 1615 |
180 | 65 | 2145 | 1806 | 1650 | 1589 | 1430 | 2532 | 2681 | 2145 | 2797 | 2237 | 1864 | 1721 |
Created with rock-bottom-calc.pl
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