Post-Trip Dive Report
Watching El Nino Underwater, 19 Sept 2024, By: William Hagey
Here’s the video log from our dive:
Here’s the time-lapse video from the past two months:
Point Loma – Acoustic Site 2 (AS2)
Vessels: The Keltic Knot
Topside Support: None
Divers: William Hagey, Paul Rahilly, and Jim Melrod
Surface conditions: Short period 1 to 2 foot mixed swell. Gray sky, calm.
Visibility: 50 at the surface, blue mid ocean water, and about 30 feet at the bottom
Temperature at depth: 56° F
Current: Strong current at the surface and the bottom. I tied the TLC off closer to the anchor to help with the swim and it helped a lot..
Dive #1: Time in: 10:47 AM, Dive length 37 minutes. (A late start because we were trying to figure out where the water was coming into the Keltic Knot.
Depth Max: 73 ft
Purpose: To replace the TLC camera, conduct a video transect, take photos and videos, and make observations.
Summary: A later start than usual. We swapped out TLCs with O2 sensors and did a video transect. Videos were taken by W Hagey with new GoPro. Jim Melrod, took stills..
Equipment Notes: There had been no big swell during this deployment so the camera was where we left it. We recovered NOAA 14 and Mini DOT551219. The UV-C had clearly protected the front window! However, it is corroded and pitted. The zinc was completely gone. It was on for 30 seconds every 6 hours. The TLC took good photos with the main light and the slave light all the way through September 10th. At that point the slave light stopped going on for photos – I imagine that it took the maximum number as set in firmware to protect the battery.
Methods: Jim took stills while I recorded video with my GoPro with dive light. Paul stayed near both of us as a safety diver. I swam a 50 meter transect at 300 degrees magnetic. I used the compass on my slate which I moved as far away from my GoPro was I could since the GoPro has magnets on it. I think the interference from the magnets was minimal. I didn’t bring my still camera. I was trying not to overload myself with equipment.
Habitat:The habitat seems much the same as last time. It seemed healthy with a good variety. There may have been more lower story algae. The video transect may show this.
Dive Details: We had a little trouble finding the TLC. I spotted about 20 meters at 120 degrees. I figure this from knowing that I swam right over the anchor at about the halfway point of the 50 meter transect. Paul, Jim and I swam down the anchor line together. Since the current was strong, I tied the TLC off closer to the bow of the boat so I would not have to swim far with it. I also didn’t bring my still camera since it would have been just that much more equipment. We found that the TLC took photos the whole two months and it was where we left it. I picked it up, and put the new one exactly where it was. I then attached the 100M transect tape to the first TLC and we swam a 50 Meter transect at 300 degrees.
The visibility was about 30 feet at the bottom and very nice. At the surface the water was a beautiful deep ocean blue with about 50’ visibility. Then, as we went through the thermocline, the water was full of marine snow. We finished our tasks with plenty of air and came back together being extra careful because of the current..
The adventures of the day: We spent extra time on the way out speeding around in Paul’s boat. This was because there was a leak into his boat that only happens when it is under way. It seems that it is the scupper that is furthest back on the starboard side.
This is an image taken from this deployment. I wish the camera was aimed a little higher to get more of the water in the background. I think I didn’t improve in this deployment… next time.
This image is from the March – May deployment with Ronan Gray in the background.
This is how NOAA 14 was deployed on 10 July 2024
This is a plot of the temperature and oxygen for the last two months.
