Page 14: of Marine Technology Magazine (March 2026)

LANDER LAB #18 ing depth using dry, compressed air. Two pressure relief valves, oil on the interior, while the exhaust was at an exterior point one a back-up for the other, vented internal air pressure as the below the lowest point of the interior, preventing water entry. system ascended to the surface at the end of the experiment. Boom. Problem solved. No oil lost to the sea, no seawater inside.

The PRVs were placed high to vent air, while the hydraulic oil was low and therefore not exhausted into the ocean. A graphite

Lesson 1: PRVs should be placed low.

burst disk provided a third emergency pressure relief method

There is a subtle problem with placing PRVs low: loose debris which gratefully never ruptured. The two PRVs, positioned at such as solder splatter, stripped wiring insulation, or lint falls the 10 and 2 o’clock positions, always worked. with gravity and may land on the PRV interior side. If air is be-

Post-deployment, however, a saltwater trail was evident on ing directed over an open PRV seal, such as when the PRV vents, the interior coming from the PRVs. Seawater in the open sump debris may land and stick on the sealing surface, compromising hydraulic oil con