22 Hours Later – We’re flying.

The Scarlet Knight is back.  Great job by the Captain, Crew and Scientists on board the sailboat Nevertheless.  Great call on the weather by Vince Cardone.  Thanks to Clayton Jones at Teledyne Webb Research for keeping the audio line open to his office. And thanks to all the people that worked through it with us in the COOLroom.  

Here’s the story, picking up from where we left off last night with the field crew heading back to the Nevertheless for the night.   With the divers back on board, we started a planned series of test dives, the first test to take 30 minutes.  We sent RU27 down about 8:50 pm, expecting a call back by 9:20.  The call never came.  All we could assume was that for some reason, RU27 could not get back to the surface.  But we knew she was a good climber.  One thing we had not had a chance to blog about yet was the tuesday night scare we just experienced as the Nevertheless left the harbor in Faial.  On Tuesday night, Scarlet was asscending from 150 m, and something held her motionless at a depth of 73 m for three minutes.  This triggerred a reversal in direction, but at this depth, that pushes the pump in to fast, causing a back voltage, turning the pump off and then triggering an abort.  The abort behavior brought Scarlet rocketing to the surface despite something trying to keep it at depth.  But now, on thursday night she was overdue, down well past 30 minutes, and well after the short 3 minute time period for being held at depth had long expired. Our next oppurtunity was at 90 minutes, with an abort triggered by no communications.  It was a long hour waiting, but once again, Scarlet proved herself and called in after the 90 minute time had expired.  We downloaded the files, and to our surprize, it had no subsurface data in the file.  The glider could not dive.  it was late, we were getting tired, the field crew was trying to sleep, so we set it to drift for the night.

In the morning the divers tied a rope and float around the tail as a safety device.  We commonly use these on the initial test run of any glider – just in case.  We tried to get it to dive, and it couldn’t.  Had we lost weight?  We added a standard pick point to the top that weights 70 grams.  The pick point couldn’t get it to dive.  Wind was increasing and so were the seas.  Tina cut some lead strips and Chip wrapped 150 grams of lead around the pick point.  If this didn’t work, she would have to come out of the water and back to shore, ending the mission.   Dave set it to dive, and we all listened to Tina’s play by play over Iridium.  Finally, after 4 very long minutes of set up, Scarlet started its first dive since she was inspected by the divers.  Down to 15 m and back.  We had established the most important fact – the glider worked.  We just had to find the proper ballast point while  she was in the water at sea.  Normally Dave does this in the lab, and we ballast to within a gram or two.  Now, at sea, we knew our ballast point had changed after the barnacles were removed, but all we knew was 220 grams was too much, and 0 grams was too little.  And time was running out.  Wind had picked up to over 10 knots, seas were building, and we had less than 2 hours left on site.  Again, we were faced with an important decision.  We could put the divers in one more time.  If the test worked, we could continue flying.  If it didn’t, we would have to pull the divers and the glider up onto the boat and head back to shore for the proper ballasting.   Clayton was on the phone with Dave, Oscar and me.  We went through every scenario possible and its consequences.  The final decision, after consulting with the field crew, is that there is no way we had 220 grams of barbacles on the glider, and that all the zincs were intact.  The 220 grams of ballast required to get the glider to submerge was also the weight required to work against the rope holding the surface float.  With that theory, we told the divers to remove the 150 grams of lead, remove the rope, and leave the pickpoint.  If we gambled wrong with too much weight, the glider sinks to its crush depth and blows the emergency weight.  Too little weight and we  don’t fly.  We decided 70 grams was our best option.  Dave gave the command, Tina gave the play-by-play.  If it didn’t sink, we were done.  If it sank to fast, we were done.  Tina called out every wave that sloshed over the glider, and every move – the air bag deflates, the nose goes down, and it sunk beneath the waves.  We got the first half right.  Tina saw it go out of site, the divers following it down, filming all the way. Now if we can get back to the surface.   Tina starts calling out she can see them again.  They are getting closer to the surface.  The glider came back up. They saw it inflate the airbag, and the phone rang in the COOLroom.  We just completed our first untethered dive since the inspection.  Dave started downloading the files.  The divers are at the surface.  Winds and waves picking up.  The data plot shows 12 cm/sec down, 15 cm/sec up, a small difference we can deal with, and the pitch was only 20 degrees.  We can increase the pitch to build the speed.  We are good to go.  The divers want to see one more dive.  Dave sends it.  A perfect dive, filmed from start to finish.  Tina pulls the divers on board.  Dave sets the glider to a deeper depth, and a steeper pitch.  The Nevertheless heads for Flores at 11:15, just 22 hours after sighting RU27, and before the weather hits.  The glider comes up, reporting vertical speeds up to 30 cm/sec.  She’s clean, and fast again.  Track plots say she is holding a course within a few degrees.  We can fix that with a small fin offset, just like in April.  Scarlet is back, and still fast.

Here’s our location, about 80 nautical miles from Flores.  Nevertheless should be back in port tomorrow morning.

The altimetry says we have a loop in the current that then heads to Flores.  We changed the waypoint to Flores, and will try to make this loop.

2000 km exactly to the border between Spain and Portugal.

Hurricane Danny is heading up the eastcoast, and will be crossing over Newfoundland on monday.

We found the best 22 hours we could find to be on site. The field crew did an amazing.  The distributed shore support provided the guidance that was needed.  All enabled by the communication network, and all before lunch.  Another day in the COOLroom.  And Scarlet is flying.