Leg 163

Review of the Scheduling of ODP Leg 163 and the implications of the 29 September-1 October 1995 Storm

An internal review has been conducted to examine the procedures by which Leg 163 came to be scheduled, the preparations that were made in advance of the leg, and the operational support provided during the leg itself.

The scheduling of ODP legs is a complex and interactive process involving the JOIDES Planning Committee, ODP/TAMU, and, to a lesser extent, the drillship subcontractor Sedco Forex, the proponents, and JOI. The dominant party in the process is the Planning Committee, but that committee needs information from ODP/TAMU and Sedco Forex on the viability of certain operations. In general, the process has worked well. Utilization of the drillship has been extremely high, with time spent waiting on weather very short.

The planning for Leg 163 cannot be separated from that for Leg 152, ODP's first leg into the Southeast Greenland margin in 1993. The two legs were scheduled in the same general area and, indeed, some of the work scheduled for Leg 163 included reoccupation and deepening of drill sites first occupied on Leg 152. It was known from the first planning stages that the Southeast Greenland margin is a particularly stormy part of the world. Hence, ODP/TAMU consulted the Danish Meteorological Institute (DMI) about ice and weather conditions beforehand. Eventually, ODP/TAMU contracted with this institute to provide the ship with weather forecasts that would supplement those routinely available as well as ice data during Leg 152 and later for Leg 163.

Leg 152 turned out to be exceptionally successful scientifically. The weather remained mostly favorable throughout the month of October but turned nasty in November. The Operations Manager called operations to a halt on November 15 when the Captain informed him that conditions were unsafe to continue. This was about five days earlier than scheduled. Therefore, when Leg 163 came to be scheduled, the Science Operator insisted that the ship should leave the area of operations by October 20.

The original intention was not to provide an ice support vessel for Leg 163. At the request of Sedco Forex, this decision was reversed and an ice-classed 80-m stern trawler, the M.V. Gadus Atlantica, was chartered for this task.

A number of questions about the scheduling of Leg 163 may be asked:

1. Did the availability of underway geophysical data, acquired quickly by small ships, make us think that the drillship could safely spend much longer in the area?
2. Yes. A successful ODP proposal depends on a suite of underway data to define the drill sites. It is now apparent that the drillship has been scheduled to operate at sites that are unlikely to be tenable for the several days required for drilling. This was understood before Leg 163, so it was planned to deploy free-fall funnels at several of the sites to allow the ship to move off and on location as conditions dictated.
3. Did Leg 152 lull us into thinking that Leg 163 would be all right? In other words, were we lucky not to encounter worse conditions on Leg 152, and were the appalling conditions encountered on Leg 163, in fact, not improbable?
4. Yes. The weather encountered in October 1993 on Leg 152 was unusually benign. However, lessons were learned here and incorporated into the planning for Leg 163, in particular the determination by the Science Operator to move the ship away from Southeast Greenland by 20 October. It is now apparent that this was too optimistic a conclusion. Furthermore, although not yet fully documented, evidence is accumulating that the fall 1995 weather in the East Greenland/Iceland area has been severe.
5. Is ODP "pushing its luck" too far by scheduling the ship to places and at times of the year that are too hazardous?
6. Yes. The conditions experienced during Legs 151/152 and Legs 162/163 suggest that scheduling two high-latitude legs per year is risky. The season is too short to allow the ice and weather conditions to be optimal for two legs.
7. Was the drillship in a "no-go" area, to which she should not have been scheduled?
8. With the benefit of hindsight, which is always 20:20, the answer to this question is probably yes, at this time of year.
9. Were the weather forecasts provided for Leg 163 accurate and frequent enough? Were they the best available?
10. An accurate forecast received no later than noon local time on 29 September would have allowed the ship to terminate drilling operations and head southeast so as to open up the distance to the Greenland coast to perhaps 100 nmi by the time the storm hit. However, increasing the frequency of the forecasts would not have increased their accuracy. With only a Force 10 storm predicted, the decision would have been made simply to wait-on-weather, as the ship has done successfully many times before.
11. Although the DMI forecast did not predict the hurricane force winds, it was probably the best available to the ship.
12. Was the other support provided for Leg 163 sufficient?
13. The support given above that available for a normal leg (i.e., the ice support vessel and an ice observer on the JOIDES Resolution) was provided to cope with the problem of ice. This support proved to be useful to the drillship in this respect.
14. Did pressures to continue operations from the Co-Chief Scientists and the Shipboard Scientific Party lead to delays in decisions relating to the safety of the ship being taken by the ODP Operations Manager, the Captain, and the Drilling Superintendent?
15. No. The Operations Manager, the Captain, and the Drilling Superintendent acted in a highly professional manner throughout, as did the Co-Chief Scientists and the Shipboard Scientific Party.
16. Are there deficiencies in the seaworthiness of the JOIDES Resolution?
17. That she endured and survived these extreme conditions is, in fact, testimony to the general robustness and seaworthiness of the vessel and to the high caliber of her crew. But it must be remembered that by her very nature of being a drillship the JOIDES Resolution has features which put the vessel at a disadvantage in extreme weather conditions. The tall massive derrick amidships is one such feature; the positioning of the bridge very far forward is another.
18. In a storm of this severity, inevitably weak points in the structure are exposed, and water will find its way into many areas. The part of the port bridge window that broke when hit by green water was a rotatable Clear View Screen. Both port and starboard Clear View Screens were replaced with flat glass windows in Halifax. The provision of metal shutters for the bridge is worth considering. Water found its way into the aft thyrig room through a corroded area of the upper deck hidden beneath a fairlead; this section of deck was replated in Halifax.
19. The thruster forward of the bridge was critical to maintaining the ship's head into the wind and sea during the storm. However, it is exposed more than any other thruster to stresses caused by heavy pitching, and it failed when a crack developed that allowed the ingress of water even as the storm was abating. The suggestion that a tunnel thruster, with the option of manual control from the bridge, would be a more robust arrangement for this forward location is worth considering.
20. To what extent should ODP schedule high-risk projects that, in worst-case situations, might imperil the well-being of the Program as a whole?
21. This is a question that needs to be considered by the JOIDES community. Hazardous Operations analyses of scientific operations that are proposed in areas of extreme environmental conditions need to be undertaken.
22. Are formal means of assessing other types of risks other than hydrocarbons necessary? Could this be achieved by broadening the membership of PPSP?
23. These are both questions that need to be considered by the JOIDES community.

Conclusion: It is necessary to program the ship's operations so that the most violent weather situations are avoided. Generally, this approach to scheduling has been rigorously observed, taking into account seasonal weather conditions, avoiding hurricane-prone areas at critical times of the year, taking prevailing winds into account, and so on. However, in 1993 and 1995, ODP, under pressure from strong competing scientific proposals, tried to squeeze too much into the short high-latitude season, with the result that neither Leg 152 in 1993 nor Leg 163 in 1995 were optimally timed. In 1993 ODP/TAMU got away with it; in 1995 the drillship was put into serious danger, 27 days of operational time were lost, and nearly half a million dollars' worth of damage was incurred.

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