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The fleet and ice management program far exceeded expectations by maintaining the drillship on location continuously over many days. The duration of the “possible” drilling operational window had been estimated to last up to 48 consecutive hours.

Prior to the expedition, SPRS thought that as much as 50% of time on site would be lost to weather, ice, and environmental circumstances. This achievement was even more remarkable given that the operations were carried out in >90% ice coverage with 7–8/10 of this composed of rugged multiyear ice.

Exceeding predicted stationkeeping capabilities proved to be critical to the success of Expedition 302 because the coring times did not meet predicted expectations. Pipe trips took twice as long, 10–12 h, core recovery averaged 1.4 m/h (a factor of ~3 slower than estimated), and the best washing ahead rate was 12 m/h.

Overall, the Vidar Viking performed better than anticipated and was able to stay on location in very heavy ice. However, the Vidar Viking’s DP system was not functional under these ice conditions, and a manual method had to be developed. The method that worked best was to provide the Vidar Viking with the near–real time ice drift predictions (speed and direction). The Vidar Viking would then set a course exactly counter to this direction. As large pieces of ice impacted the ship, the Vidar Viking “leaned” toward the broken ice by driving ~20 m upstream of the drill site location and then slowly drifting with the ice to ~20 m downstream from the drill site location before repeating the same process again. Thus, accurate ice drift direction was critical for positioning. When the prediction was wrong, the Vidar Viking would not drift back exactly over the drill hole. Once the vessel was off-track, it was difficult to move sideways back to the optimal track path again because of the heavy ice to port and starboard. When ice became too difficult, the Oden broke ice close to the Vidar Viking so that the ship could maneuver sideways. These tight maneuvers were successful because of the experienced and capable captains who trusted each other.

Because of the critical nature of the ice drift direction, predicting direction became a high priority for the ice management team. A new approach for measuring ice speed and direction was developed by SPRS and used successfully during Expedition 302. By helicopter, radar reflectors were placed on selected ice floes and their positions were tracked upstream of the drill site location.

The biggest problem in predicting ice drift was when the wind speed dropped and wind measurements became unreliable. On these occasions, the whole ice sheet “stalled” and began to rotate because of Coriolis forces. This caused significant problems for the Vidar Viking because a regular heading could not be maintained and maneuvering became almost impossible. During some of these times, drilling was temporarily suspended (keeping the drill pipe in the hole) until ice began to move again in one direction. Stationkeeping was best achieved during conditions of steady, predictable ice drift. However, even during these severe events, the watch circle limit (100 m) was never exceeded (Fig. F5) The largest deviations from the center point occurred during conditions of no ice drift and when the ice sheet revolved 360°. The ice management team gained experience during the expedition and succeeded in making accurate predictions even during times of low wind speed, which improved the difficult situation for the drillship.

The ice alert system used during Expedition 302, based on experience from the offshore industry in Sakhalin, served very well as a tool for documenting the operations but was of limited value during critical times when rapid decision-making was required. During these situations, the Fleet Manager relied most heavily on the ice drift and meteorological predictions.

The Expedition 302 communication system, provided under subcontract by Per Frejvall, long-time consultant to SPRS in matters of IT and communication, was also important to the success of the operation. Full cellular coverage, provided by Eriksson Response, was installed on the Oden with links to the Vidar Viking and the Sovetskiy Soyuz. In addition, the ships were linked 24 hours per day, 7 days per week by Internet. These systems, in addition to ships’ radios, made communication almost seamless. Fleet management provided frequent and regular updates to the fleet bridges on the current ice situation specific to each vessel. This system also enhanced communication among the ships' captains. After the first week, the captains became more familiar with each other and learned quickly what each vessel and crew could achieve. This level of familiarity and trust played a large factor in the fleet’s ability to keep station for ~9 consecutive days at the last site. Also, as operations continued, maneuvering and vessel coordination were fine-tuned, and this significantly reduced the amount of power required for icebreaking.