Dive_Blog_2024_10_10_PL4
Purpose: Watching El Nino Underwater, Swapping of TLCs
October 10 2024
By: William Hagey
Here’s a video of our dive:
Here’s the video made from the time-lapse camera from the past two months:
Vessels: The Celtic Knot
Divers: William Hagey, Paul Rahilly, and Jim Melrod
Topside Support: None
Surface conditions: Calm 1 to 2 foot swell. Overcast becoming sunny.
Visibility: 40 ft
Water Temperature: 53° F
Current: Strong current going south at the surface. Not so strong at the bottom
Dive: Time in: 10:40AM, Dive length 35
Depth Max: 74 ft
Purpose: Swap out TLCs, Video transect. (The transect was done to and from the anchor and video was recorded around the site.)
Summary: The TLC and Mini DOT were replaced with new units. Video was taken by W Hagey with new GoPro 12. Jim Melrod took stills.
Equipment Notes: We recovered the TLC and O2 logger. They had not moved during the deployment and were still taking pictures with the slave still working and no biofouling on the front window of the camera. This is evidence that theUV-C light is protecting the window. The slave light and UVC lights were still working with plenty of extra battery life. (The slave and UV light pack had 5 AH at 14.8V (two battery packs diode ORed together. This was plenty of power.) TLC NOAA2 was with MiniDot SN142025, slave light – with a delay and the, and a UV-C antifouling light. A zinc was also added to the UV-C light bracket, but was completely used and UV-C light was pitted. I didn’t expect this since the bracket was 300 series stainless steel.
NOAA 13 was deployed with the UV-C light. And since it had been badly corroded when it was last deployed I encapsulated the whole UV-C light in urethane, WC-575, for this deployment, to be sure. A 5-pound bright yellow dive weight was added to the bottom of the TLC as additional anchoring in case a large swell rolls through in the coming months.
Habitat characteristics and surveys: The kelp is coming back to this site. There is noticeably more upper story kelp that can be seen in the dive videos. The bottom is hardscape with pits and a gentle slope. There is upper and lower story macroalga. This location is well known since it has been a release site.
Methods: We dropped anchor closer to the TLC than the PL4 coordinates. Paul quickly found the TLC and lead us to it. This gave us plenty of time to swap out the TLCs. I took plenty of video with my GoPro 12 and Jim took stills with his new strobes.
A 50 meter transect was not run but I did recorde video of the area and on the way back from the TLC to the anchor.
Abalone: We were so focused on our task, with the very low light and strong current so we didn’t look around for abalone.
Dive comments: Strong current at the surface. Paul put out a line and float behind the boat. The water was very clear. This allowed us to explore around a bit and see the area and better understand the topography. While the water was not the same ocean blue it had been, it was kind of grayish, the visibility was still wonderful!
This is the oxygen and temperature profile from this deployment
See photos below:
The upper image is from the newly recovered TLC and the image below is from the TLC that was recovered in August. Note, good and similar alignment.
This is a reverse angle showing the TLC from behind the rock that is in the foreground of the time-lapse images.
Paul and Jim are returning to the anchor through elk kelp with a school of mackerel in the background.
