OCEAN SCIENCE AND ENGINEERING p.47, Ben Oostdam's Autobiography

Because the navigation beacons worked poorly, Petru van Zyl and Cyril Gradwell used theodolites (transits) from beacon-benchmarks ashore every 15 minutes for 3 days, transmitting their readings to the bridge so we could plot drill-holes accurately.

Two drill crew members adding a 30 foot pipe

Willie and I made one dive to determine the sediment type and drill cone configuration. Willie and Des monitored and sampled the sediment flow, while I did most of the navigation and plotting -and in between played chess with Jerry and Captain Cook.

showing Rockeater anchored near-shore in Chamais Bay: part of derrick: right bottom front pipe from drill to processing plant on forecastle: right top articulated crane to handle drill pipes: bottom left f'd of boat

sampling line 116 1/2 [line numbers represent distances in kilometers from Orange River Mouth (to the right on chart segment below)]