US family and employee-owned towage company Crowley has described its part in the loadout of a mobile spacecraft launch platform.

Dry tows are where as opposed to wet tows, the object is transported on a heavy load carrier. Tugs are still required however for positioning the object over semi-submersible type vessels and removing it at journey’s end and Crowley’s recent such involvement has highlighted how best laid plans must be changed thanks to the weather.

The task involved assisting with transport of the self-propelled, semi-submersible mobile spacecraft launch platform LP Odyssey from Port of Long beach, which had been its home for more than 20 years, to the Russian east coast, just south of Port of Vladivostok.

A dry tow was chosen, the platform loaded aboard the China COSCO Shipping-owned, semi-submersible heavy load carrier Xin Guang Hua and Crowley’s role involved towing LP Odyssey from Los Angeles Harbour to an outside anchorage near Long Beach for the transfer.

In less than 48 hours, the tugs Master, Leader, Admiral, Veteran and Scout were mobilised including complying with customer and regulatory requirements. The tugs started to tow the 436’ long, 220’ wide platform to the Xin Guang Hua in the anchorage but as is often the case in the world of seafaring the weather had other plans and sea swells delayed the final set down of the platform onto the ship.

Authorities and Crowley’s operations team ashore developed an alternative plan where it was agreed the best course of action was to move both platform and heavy load ship back inside the harbour breakwater for the loading operation. A window to minimise port traffic interruptions was established and two days later with the aid of the tugs, LP Odyssey was safely positioned over Xin Guang Hua which was deballasted allowing the platform to be fastened securely for its journey to Russia.

Crowley’s Master, Leader, Admiral and Scout would have been well-matched for their role being four of Crowley’s five US-flagged, 50tbp Harbor Class, Voith Schneider-propelled tractor tugs built by Nichols Bros Boat Builders in 1998/99. The fifth tug assisting, Veteran is another Nichols-built tug, dating from 2014 and one of two Valor Class tugs providing over 90tbp from Rolls-Royce Aquamaster Z-Drive units.

By Peter Barker