Trina (APL-UW) does final preparation and checkout of a SAMI-pH sensor before the Platform Interface Controller is deployed. Credit: Mitch Elend (UW);V15.
The term “roller coaster” invokes images of violent undulating motions that peak and ebb and almost certainly force objects in directions that may be resisted but rarely overcome. But the term is also often used to express the emotional ups and downs that can accompany series of events occurring during our lives. Aboard a research vessel, one can easily experience that phrase’s meanings in all its various physical and mental forms.
A few days ago on the morning of July 31st, the R/V Thompson left Newport for the start of Leg 3 of the Cabled Array VISIONS’15 cruise. The UW scientists and engineers have been joined by our colleagues from Oregon State University (OSU) for the task of performing maintenance on the cabled components of the Endurance Array (EA) on the Oregon shelf. A few new students and a few returning students from Leg 1 are also onboard and will be learning about and assisting in the deployment and recovery of various instrument packages, some of which are specially designed to protect them from fishing activities dominant in coastal waters, e.g. trawl-resistant platforms on the seabed.
As we passed the entrance to the harbor, the ship’s smooth seaward travel was quickly transformed to a ride not unlike that of a roller coaster as the ship bucked and rolled in the high winds and waves that were waiting for us just outside the jetty. Luckily, a little over an hour later and 10 miles out, we arrived at our first station: EA Shelf Site (80 m water depth). The ship’s motions were quickly subdued as it was expertly positioned relative to the wind and waves. But just as swiftly, the ship’s deck exploded in a flurry of activity as preparations were made for the first ROV dive to recover a sea surface-piercing profiler from the seabed. Simultaneously, the combined OSU-UW team continued to prepare other instruments and platforms for deployment on subsequent dives. Such preparations are critical as these ROV dives in shallow waters can occur in rapid succession. As long as weather and sea-state conditions are favorable, the activities are rigorous and continue 24/7.
After that first dive, though, the wind and waves quickly combined to form conditions that were determined to be unsafe and ROV dives with instrument packages were put on “weather-hold”. The team waited impatiently, continually monitoring weather forecasts and sea conditions and hoping for windows of opportunity to continue the work that must be completed during the fixed time of Leg 3. Over 24 hours later, the seas finally calmed down, and an elated and rejuvenated team quickly ramped up their work. Over the next 16 hours, three ROV dives were performed and deployment/recovery tasks for all instruments at this site were completed. As we transited to the next EA site further offshore (600 m water depth), we began careful monitoring of the weather conditions, knowing very well that a similar roller coaster of activity would be repeated there.