Daily Log - Day 5
Awoke to another beautiful day at-sea — five more days of this would be heaven (but not likely given forecast for this weekend). Land-based scientists can operate independently of weather in most cases. Out on the ocean, it is at the same level of importance as eating and sleeping, both of which it can severely impact. We are definitely limited by sea state in AUV and ROV operations. The bottleneck is getting the vehicles in the water and back on deck. Like the adage that most car accidents happen a mile from home, most damage and injuries occur in the short span of time it takes to cross the air-sea interface. Sea state is reported in various ways; most common is the Beaufort scale which assigns numbers from 0 (calm) to 12 (hurricane). We do not operate in anything above Force 5 (wind speed 17-21 knots, wave heights 6-8 ft.). Yesterday was Force 2 (wind 4-6 kn, waves 1 foot), today is Force 3-4 (wind 7-16 kn, seas 2-5 ft.), tomorrow?
I spoke in an earlier log about the new breed of cyber-oceanographer that will be required for the new age of technologies (e.g., AUVs). For comparison, when we go on a scuba diving mission, it may take an hour before the dive to prepare, including 2 “check-lists” for the dive plan and gear status. Occupied submersibles involve a few more checklists to cover sub equipment status, and a few hours to prepare for a dive. The NURC Remotely Operated Vehicle (Phantom S2) involves 3 lists to prepare to dive and about two hours of preparation. Eagle Ray AUV has 11 different pre-dive check-lists, and 3 post-dive lists. Dive programming, inspections, maintenance, and start-up procedures take almost 4 hours before each dive, not including the 10-13 hours of battery charging required between dives. In addition, they stand watch for up to 12 hours each day. Occasionally, the AUV team gets to eat, sleep, and watch the weather.
We recovered cruise dive 3 at 0800 after a fitful dive in the deep portion of the Oculina Experimental Closed Area. We have the vehicle returning to surface after every other survey line (2-3 hours), so we can give it a new geographic fix; normally we could update the vehicle using the Ultra-short baseline (USBL) positioning system, which is still not functional. This cuts into battery life and survey time. We may not be able to get back in the water until tomorrow morning, so we can launch in daylight. Today will be spent processing data and preparing for next dive, including trying to fix some of the almost 50 bugs we now have encountered and remain to be resolved.