Steelhead is back

We pulled up to station 220 around 9 PM and sent a few release commands to receiver Steelhead but heard no replies. The Sikuliaq has a deployable centerboard that extends several feet below the hull and so we’ve been using the transducer on the end of the centerboard since that’s a less noisy environment for a transducer than up on the hull where more water turbulence and air bubbles can muddle the incoming pings. For almost all of the receiver recoveries that has been working really well.  But alas, we couldn’t get any commands through to Steelhead, though we did sporadically get a reply when trying to range on it so we knew it was still alive (in the acoustical communication sense). Earlier in the cruise Jake noticed another receiver that was hard to communicate with, but which worked just fine when we switched to the ship’s hull mounted transducer (as opposed to the centerboard ducer). So we switched to the hull transducer and bam – it acknowledged its release command on the first try! About four hours later we landed it on deck.  So new numbers for the cruise:  159 deployments and 159 successful recoveries. Coupled with the 168 deployments and recoveries we did on the HT-RESIST survey earlier this year, that’s makes for 327 total deployments without a single loss of instrument this year. To be fair, we did have two receiver frames and some sensors destroyed when the ship ran them over during their recovery this cruise, but we still got the data loggers (and the data) back.

Steelhead was back on deck around 1 AM with a nice turnout of the science party to celebrate the final instrument recovery.
Ocean bottom EM receivers stacked and ready to be craned off the ship when we arrive in Seward.