Sea019 m49 ballast alarm (64)

[richardsc]

During Sea019 M49, we experienced several "Ballast" alarms. Because we didn't know what was causing them, and the glider had only just been deployed, we decided to recover it and replace with Sea021.

Apparently this alarm occurs when the ballast position goes farther than the ballast command, but we have no indication what could have caused that to happen (at least twice).

Note that this was with Sea019, which is the glider which on a previous mission (M43) not only hit the bottom several times, but also lost the dropweight and drifted at the surface for several days. The possibility that something may have happened to the glider shouldn't be discounted.

[melanybelzile]

Marion suggested that maybe because the glider went higher than 10m in muti dives, 2 valves were opened instead of one. But we don't understand fully how it would impact the oil volume as the piston is what set the amount. Also, se had another hypothesis on the timing of the cycle. We would like more precision on this.

Would it be an option in the future to set the 20 ml threshold of this alarm to a bigger number?