International Dredging Review

International Dredging Review

The Corps hopper Dredge Yaquina turned 30 in June and Mac Robison chief of the Portland District Plant Maintenance Section has been with the dredge throughout its life.
The shallow draft hopper dredge (16 feet fully loaded) was built to maintain federal channels in the Pacific Northwest and Robison was one of three resident district engineers who rotated to Norfolk during the Yaquina’s construction at Norfolk Shipping and Drydock’s yard in 1980 and 1981.

In March 1981 after doing a small project for the Norfolk District the Yaquina sailed down the East Coast through the Panama Canal and up the West Coast to its home in the Portland District. A formal commissioning on June 12 of that year sent the dredge into service and the assignment to dig 1.5 to two million cubic yards of maintenance material every year on the U.S. Northwest Coast.

Robison is now overseeing a complete re-powering of the Yaquina spread over several years in three stages and finishing up with the replacement of the pump engines late this year. The District is in the process of soliciting bids for that work which is expected to be complete by April 2012.

The repowering replaces all the original Caterpillar engines with Tier II MTU engines.

In March 2009 the bow thruster engines were replaced and in March 2010 the two SSDG’s (ship service diesel generators) were replaced.

The original 18- by 16-inch dredge pumps have been replaced with GIW 20- by 20-inch pumps. Also a new dragarm control system was installed in March 2009 by Peter deJong of DACS.

The Yaquina’s work locations include mainly shallow draft harbors on the Oregon Coast down to Moro Bay in California and including Grays Harbor in Washington.

“In the past she has worked in Hawaii and Alaska” said Robison.

The two crews include 19 people each led by captains Mark Keen and Steve Ackerman. The 26-foot Launch Yaquina is stored on deck and doubles as a survey boat using a Ross Survey System.