leak detect value rose after the abort to ~2.2, but short fell again, and remained around 0.8 throughout the night

glider drifted overnight.

Recovered by Palmer team at 7:15am Eastern Time 1/25/2020

light interaction on the final climb before leak. it almost looked like it was penetrating a gradient but data didnt really show any at 40 m. maybe krill? other climbs didnt do it.

it was wobbling about +- 5-10 degrees, could have been another system adding noise to glider.

(segment ud_476_2020_013_0_302, 0115.0302)

forward leak:

ABORT HISTORY: total since reset: 2
ABORT HISTORY: last abort cause: MS_ABORT_LEAK
ABORT HISTORY: last abort details: There is a leak in the forward compartment.
ABORT HISTORY: last abort time: 2020-01-25T01:29:44
ABORT HISTORY: last abort segment: ud_476-2020-013-0-304 (0115.0304)
ABORT HISTORY: last abort mission: 200_N.MI


leak happened at about 8m, first dive of segment.

glider possibly was gaining weight whole mission - maybe slow leak?

sensor: u_reqd_depth_at_surface(m) 2.5
sensor: u_abort_max_burn_time(sec) 72000 # drop weight after 20 hours in abort mode, up from 4

# sensor: f_fin_safety_max(rad) .41

# Altimeter settings
# sensor: u_alt_min_depth(m) 100
#sensor: u_min_water_depth(m) 225
sensor: u_max_water_depth_lifetime(yos) 0
sensor: m_altitude_rate(m/s) -1
sensor: u_alt_reqd_good_in_a_row(nodim) 4

sensor: u_min_altimeter(m) 2.0 # in, altimeter reading must be between these(inclusive)
sensor: u_max_altimeter(m) 10.0 # the maximum range of the altimeter

Running an iridium 853 segment at 12 sec sampling, single yo to 185, should be this segment:
ud_476-2020-013-0-234 (0115.0234)

Changed u_reqd_depth_at_surface from 3 to 2.5. May be able to go lower than that.

u_alt_min_depth 185. According to bathy shallowest line gets if you run it well is 230 m.

u_min_altimeter 2, u_max_altimeter 10. Its not getting any returns past 20 m, most are 15-20 m. Figured maybe if shallow range is working lets allow it. This will have some early returns but perhaps u_alt_min_depth can limit it.

Turned optical sensors on at surface. Adjusted TBD to have critical sensors for surface reporting too. TBD is about 30 KB now, see how much it goes up by.

No altimeter hits beyond 18 m. Noticed similarities to this issue last deployment, 2018. Also many hits show up at 18 m so a static offset. caused early turn arounds.

Altimeter likely not working far ranged, may still work short ranged according to last mission.

May change altimeter settings to close range only, 2m to 12m should remove most of the hits but it will still turn around early.

Trying 'enhanced' waypoint list with multiple along the line and no surfacing for waypoint. Also some movements on the tail end of the lines so that its more likely to surface near the line. Double yo's.

!!!! u_alt_min_depth 140 !!!!

!!!! u_alt_min_depth 50 !!!!

sending to Swarm line between Joubins and Wauwermans - running 200_nw.mi

redid zero_ocean_pressure - m_depth was at 0.25m --> m_depth now 0.017m

.853 files being generated, ping rate should be around 1 sec

TA120613.853 258,304 01-12-20 6:30a
TA120651.853 246,528 01-12-20 7:07a
TA120728.853 236,544 01-12-20 7:44a
TA120823.853 243,968 01-12-20 8:39a
TA120859.853 237,824 01-12-20 9:15a
TA120937.853 242,688 01-12-20 9:54a
TA121033.853 255,232 01-12-20 10:50a
TA121111.853 243,200 01-12-20 11:27a
TA121148.853 267,264 01-12-20 12:06p

every 30 min close date is what we expect at 200 m dives, only downs

# 2019/1/1 dkaragon initial
# 2019/1/2 dkaragon eased off fin limits for better steering with azfp, altimeter hits on krill, it turned around early even with u_alt_min_depth I think because of old hit
# 2020/1/10 dkaragon initial ud_476

sensor: u_reqd_depth_at_surface(m) 3
# sensor: u_abort_max_burn_time(sec) 72000 # drop weight after 20 hours in abort mode, up from 4

# sensor: f_fin_safety_max(rad) .41

# Altimeter settings
sensor: u_alt_min_depth(m) 100
#sensor: u_min_water_depth(m) 225
sensor: u_max_water_depth_lifetime(yos) 0
sensor: m_altitude_rate(m/s) -1
sensor: u_alt_reqd_good_in_a_row(nodim) 4

Note: noticed on first deploy attempt NBD that the CTD pressure sensor was noisy, about .2 m peak to peak and reading about .25 m shallow. Unsure if still the case on 2nd deployment.

No CTD cast performed on deployment. Other Swarm gliders (unit_507 and RU32) will all station keep together for a bit to cross-compare CTDs.

segment 0112.0002, ud_476-2020-009-2-2: 1 hour to 110m (same as yesterday when leak triggered). This time successful, no leak!

Shallow.mi segment: 0111.0000, ud_476-2020-009-1-0

CTD and glider pressure sensors did not agree. CTD was 0m while on surface and glider was not. Glider was 1.5m shallower than CTD at depth.

re zero_ocean_pressure before starting 200_n.mi, continue to monitor.


***Update - after the first segment, 1hr mission to 60m, 0112.0000 (ud_476-2020-009-2-0), pressure sensors agree.

Deploy attempt yesterday, 01/09/2020 - ud_476 aborted for aft leakdetect at end of first segment to 110m - aborted on the upcast.

Glider was recovered. Found tie-rod was not very secure. Found a small drop of water on the aft leakdetect. No damage noticeable on o-rings. Potentially a little dirty though. Aft o-rings were replaced. Glider resealed, wiggled, no errors.

Redeployed UD_476 today

Glider: UD476
GliderDos Version: 8.2
Instrument Type: CTD, FLBBSLC, BSI PAR, Imaginex 853 Echosounder, Aanderaa Optode
Instrument Serial Number: 9537, 5499, 50283, 8367, 334
Instrument Cal Date: CTD 1/29/19, FLBB 2/14/19, PAR 2/15/19, Imaginex 853 7/2019 (in house), Aanderaa Optode 6/2019 (@ Rutgers)