Expedition 402T: Transit and Tie-Up

Zenon Mateo

Summary

Expedition 402T started on 8 April 2024 from Napoli Italy and ended in Amsterdam, The Netherlands on 4 June 2024. The 10-day transit started from 07:00H on 12 April 2024 until 1048H on 22 April 2024, covering about 2447.86 NM (GPS data) in 243.8 hours, for an average speed of 10.0 knots. This was followed up by a tie-up in Damen Shipyard Berth #3 and 4 in Amsterdam. The 12 kHz Knudsen 360 singlebeam echosounder was used for the entire voyage, with the 3.5 kHz only limited to the Alboran Sea and Strait of Gibraltar segment. All 34 SEGY files (6.2 GB) were imported, sometimes in segments, into a Petrel project file in order to verify data quality and handling.

This concludes the last marine transit for this JRSO crew aboard the JOIDES Resolution.

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Figure 1: Maps showing the overall transit line overlain on Bing map (left) and the CHIRP survey line on EMOD Bathymetric map (right) for Expedition 402T from Napoli, Italy to Amsterdam, The Netherlands. Plots are from NaviPac Helmsman, WGS 84 ellipsoid, UTM 31N projection.

Activities

Navigation data was compiled and collected using NaviPac 4.6.0.15803 (rev81339). Ship-wide navigation display used Google Earth and JRGE.

For the outbound transit from Berth 5 Molo Angioino, Napoli, Italy, the harbor pilot boarded the vessel at 06:54H and the last line was released at 07:19H

MRU data for NaviPac and navigation data for JRNav were not recorded from 17- 22 April while the engineers were working on iRIS.

Arrived with first line ashore at Damen Shipyard Berth 3 at around 10:48H on 22 April 2024.

Distance travelled: planned transit = 2439.8 NM (based on waypoints); reported on DOR = 2412 NM; re-sampled (per minute) NaviPac GPS data and displayed in Helmsman = 2447.86 NM

The 12 kHz profile was collected throughout the transit from Napoli to Amsterdam, starting on 12 April 2024 at 0825H (40 41.16748N, 14 11.67677E) and ending on 22 April 2024 at 1050H (52 24.28398N, 4 52.98258E).

In using the 12 kHz, this transit showed how it is easily affected by seastate. There also appears to be an upper and lower depth limit in the sub-bottom penetration, such that only the seafloor profile was captured in the very shallow waters of the English Channel, whereas the sub-bottom profile was imaged in the Mediterranean (Fig. 2). Also, in shallow waters, the lower depth limit should be set to zero in order for the software to properly recognize the seafloor and not the multiple, which may have a stronger signal than the primary reflection.

The 3.5 kHz was only used to profile the crossing through the Alboran Sea, through the Strait of Gibraltar. A complete profile was collected, all the way across the Camarinal Sill.

Figure 2: Still superbly performing after the maintenance work done by E. Moortgat and E. Classeen! Snapshot of the 12 kHz CHIRP profile taken 141 km south of Ibiza, Spain showing numerous seafloor mounds. Achieved about 15 m of penetration at 10 kt speed in calm Mediterranean Sea.

Table 1: List of CHIRP profiles acquired during Expedition 402T.

1. Prepare PPT slides. Conduct lecture and laboratory exercises on Introduction to Micropalentology for JR Academy.

2. Collect and analyze 24-hour NGR background data while the vessel is stationary and compare with corresponding magnetic field (space weather) data from nearby INTERMAGNET observatories.

3. Review and update UW and DHML Confluence documents for legacy documentation.