Question

My buddy and I are planning a shore dive. we're descending onto a very gradual slope that begins at 5 m/15 ft, so our descent and ascent will be a gradual part of swimming out and back underwater. we have similar cylinders filled to 2000 bar/3000 psi. We plan:
- 50 bar/500 psi reserve
- 20 bar/300 psi for our safety stop
- to turn the dive when we've used 1/3 of the air available to use on the dive

This means we should head back when either of our SPGs read
A. 70 bar/800 psi
B. 145 bar/1900 psi
C. 157 bar/2270 psi
D. 170 bar/2500 psi

Answer 1

Answer:

C. 157 bar/2270 psi

Explanation:

Calculation to determine what we should head back when either of our SPGs read

SPGs=200 bar -[200 bar-(50 bar + 20 bar)]÷1/3]

SPGs=200 bar-[(200 bar-70 bar)÷1/3]

SPGs=200 bar-(130 bar÷1/3)

SPGs=200 bar-43 bar

SPGs=157 bar/2270 psi

Therefore based on the above calculation we should head back when either of our SPGs read 157 bar/2270 psi