[PSUBS-MAILIST] Tahoe summary

Sun Jul 1 17:08:46 EDT 2018

Hi Cliff, Alec,

Congratulations on your testing and retrieval.  Sounds a really fun few days.

Looking forward to the video footage.  Hugh 

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alec Smyth via Personal_Submersibles
Sent: Sunday, 1 July 2018 6:35 AM
To: personal_submersibles at psubs.org
Subject: [PSUBS-MAILIST] Tahoe summary

Hi friends,

A bunch of PSUBers have just wrapped up a week diving R300 and Nekton Gamma in Lake Tahoe, so I thought I'd summarize how it went. 

This was the first expedition planned with the framework of https://www.innerspacescience.org to align the use of personal subs with science objectives. That allowed us to partner with three organizations - UC Davis's Tahoe Environmental Research Center, the California Tahoe Conservancy, and the Tahoe Regional Planning Agency. They facilitated everything from our boat inspections to finding a base of operations on land, but above all provided institutional-grade surface support vessels as well as scientists. 

One of the first objectives was to depth test R300, and she passed with flying colors (no surprise!) Cliff had a cool way of doing the test. Since everything on R300 is controlled by a PLC, he programmed an entire automated dive cycle beginning with a 45 minute delay.  He attached ballast to replace the pilot, clicked a button to start the clock, and closed the hatch. The timer gave us time to tow the boat out to depth, then automatically flooded ballast.. Attached to a line, R300 descended to around 400 feet, stayed there half an hour, fired vertical thrusters to rise, and a few feet from the surface blew ballast. 

Another objective was to shoot some sub-to-sub video. That day the visibility wasn't optimal, but we did get it. It was the first time I'd done a multi-sub dive and it was as much fun as you'd expect. Video to follow...

The scientists had a bunch of objectives. In general we did not have the bottom time to carry out the methodical counts they were attempting, but we were able to get their eyeballs on the spots they were wanting to make the counts at, and get video. Some hypothesis were met, but new questions arose too. One of the spots they wanted to study was the top of an UW mount. Hank was able to find it, climb up, and circle the top. That was an accomplishment, because the top was only about 20m across and we were unable to locate the mount with depth sounders from the surface even when provided GPS coordinates. These spots were in 200’ plus, so had not been visited on SCUBA.

We were able to offer Gamma rides to a few VIPs but more importantly to many young students. You should have seen the reactions. Another time, Cliff beached R300 on a popular sandy beach and found himself giving an impromptu lecture to a circle of young people. 

The most exciting incident came on the last day when Cliff gave Jon and Dave some training followed by solo dives. On Dave’s dive one of the side thrusters sucked in a rope and he found himself tethered to the bottom in 77 feet. Minutes later the surface support boat’s outboard accidentally cut off the comms transducer. However, Dave followed R300’s emergency plan to the letter and blew MBTs, which ripped him free. Unfortunately we don’t have video of that incident, but it would have reflected well on all involved. The sub had a pinger to locate it, had a plan, and the plan was followed.

Now we need suggestions for the next expedition!

Best,

Alec

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