Leg 187 began at 1815 hr on 16 November 1999 when the first line was passed ashore to Berth H of Victoria Quay at Fremantle, Australia, at the conclusion of Leg 186ST. During the port call, several pieces of scientific apparatus were serviced (microscopes, XRF spectrophotometer, and cryogenic magnetometer), and the new ICP spectrophotometer was installed in the chemistry laboratory. The Ryan Energy Technology Fusion rig instrumentation software installation, which was started in Singapore during the dry dock, was also completed. The drill crew finished the assembly and static testing of the passive and active components of the heave compensator by the morning of 21 November. The project was complicated by the discovery that a defective directional servo valve in the active compensator required replacement. A local Bosch supplier expedited a replacement part from Adelaide during the evening of 20 November. Our departure was also delayed because the Fremantle tugboat operators conducted a 48-hr work stoppage starting the morning of 19 November and lasting until 0900 hr on 21 November.
At 1210 hr on 21 November, the last line was released from the pier and the JOIDES Resolution (JR) was maneuvered into the channel. After the pilot departed the vessel at 1300 hr, the JR began steaming at full speed on a southerly course.
Before proceeding to the first location of the leg, the ship was required to make a small diversion to a site off Albany in southwestern Australia. This was done in order to perform acceptance testing of the newly installed active heave compensator and the Fusion rig instrumentation system. The brief testing period also allotted additional time for crew familiarization with the new systems. The 401-nmi journey was completed at an average speed of 9.6 kt in calm seas and under fair skies.
The 1-day testing program began at 0615 hr on 23 November with the deployment of a positioning beacon in ~285 m of water. Once the vessel stabilized over the beacon, the active heave compensator and the Fusion rig instrumentation were tested during mock coring exercises. Tony Muir, the Maritime Hydraulics representative, demonstrated the seafloor landing capabilities of the active heave compensator for the drilling crew during hands-on training exercises. John Grow, the Ryan Energy Technology representative, introduced the features and demonstrated the operation of the rig floor display to both drilling crews.
The testing exercise was completed in the early hours of the next morning. Once the drill string and beacon were recovered, the vessel sailed ~22 nmi to a prearranged rendezvous point between Breaksea Island and Bald Head at the mouth of Albany harbor. The M/V Avon came alongside at 0745 hr; Tony Muir, John Grow, Derryl Schroeder from the Ocean Drilling Program/Texas A&M University (ODP/TAMU), and Stefan Stan (representing Siemens) boarded the Avon. By 0800 hr on 24 November, the JR was under way at full speed to the first site of Leg 187.
The 616-nmi transit to Site 1152 was accomplished at an average speed of 11.8 kt. The vessel rode well in a combined sea/swell of 10 ft. There was an occasional burst of wind-driven spray over the bow as the ship proceeded on a southeasterly heading. The skies were overcast with good visibility. At 0800 hr on 26 November, the vessel slowed to 6 kt while the seismic equipment was deployed. The objective was to conduct a single-channel seismic (SCS) survey across the precruise survey line. Data obtained from the survey were used to find localized sediment cover. An initial review of the seismic record suggested a sediment layer possibly 70 m thick overlying basement.
By noon, a north-to-south seismic line was concluded and the seismic equipment retrieved. The vessel came about and slowly approached the location. A beacon was dropped on the prospectus Global Positioning System (GPS) coordinates at 1215 hr. After the hydrophones and thrusters were extended and the vessel settled on the location, the corrected precision depth recorder (PDR) depth referenced to the dual elevator stool was 5066.4 m. A nine-collar bottom-hole assembly (BHA) was made up, comprising a C-4 four-cone rotary bit, a mechanical bit release, a head sub, an outer core barrel, a top sub, a head sub, seven 8¼-in drill collars, one tapered drill collar, six 5½-in drill pipes, and one crossover sub. Although no logging was anticipated, the mechanical bit release was affixed as a means of freeing the BHA should the drilling assembly become stuck at the bit.
Hole 1152A was spudded with the rotary core barrel (RCB) at 0830 on 27 November (Table T1). The bit tagged the seafloor at 5066.4 m. Instead of coring into a sediment pond, the bit appeared to contact hard rock immediately. After RCB coring 11 m with slow penetration and high and erratic torque, we decided to again attempt to contact sediment by offsetting the vessel upcurrent of the present location. The vessel was repositioned in dynamic positioning mode ~100 m north-northeast of Hole 1152A.
Hole 1152B was spudded at 1330 hr and was washed ahead to 22.6 mbsf where we encountered a hard contact. Rotary coring was initiated in basalt at this sub-bottom depth and advanced to 40.6 mbsf with low recovery. At this depth, the drill string stuck and stalled the top drive. The driller worked for 1.25 hr to free the drill pipe with overpulls as large as 100,000 lb to regain control of the situation. After freeing the drill string, the interval from 40.8 to 45.3 mbsf was cored with improving recovery (28%). The bit was only advanced 1 m to 46.3 mbsf when the drill string stuck again. This time the drill pipe was freed with 40,000 lb of overpull. It was obvious at this juncture that the hole was too unstable to deepen, so coring operations were abandoned. The bit cleared the seafloor at 1500 hr and cleared the rotary table at 2345 hr on 28 November. Concurrent with the retrieval of the drill string, the beacon was successfully recovered. After the thrusters and hydrophones were retracted and the drilling equipment secured, the vessel was under way to the next site by 0000 hr on 29 November.
The average recovery of the site was 12%, providing adequate material to attain our scientific objectives. During the operations at this site, the environment was very mild for this region, with vessel heave not exceeding 2 m.