Published Aug. 31, 2012
The Dredge Essayons, a deep draft ocean-going hopper dredge, was repowered by the Marine Design Center in 2009.

The Dredge Essayons, a deep draft ocean-going hopper dredge, was repowered by the Marine Design Center in 2009.

Vessel Owner:                      United States Army Corps of Engineers
Repowering Shipyard:          Cascade General, Portland, OR
Project Management Team:  USACE Marine Design Center and Portland District
Vessel Operation Team:        USACE Portland District, Portland, OR

Vessel Particulars:
Length Overall:         350’
Hull Breath:              68'
Hull Depth:               35
Portland Ownership:  1983
Max Hopper Load:     6,423 cu yds

New Machinery, Equipment, and Special Features
Propulsion Engines:                              (2) CAT C280-12, 4,640 HP ea, 900 RPM
600 V Generator Engines:                      (2) CAT C280-12, 3,250 kW ea, 900 RPM
Propulsion Reduction Gears:                  (2) Haley Marine Gears - Ratio 5.792:1
600 V Generators:                                 (2) Kato Engineering, 3,250 kW ea
Ship Service Generators:                        (3) CAT 3512C, 1,030 kW ea, 480V output
Emergency Generator:                           (1) CAT C18, 425 kW, 480V output
Integrated Control & Monitoring System:  Siemens Energy and Automation, Inc.
Propulsion Control System:                    Bosch Rexroth Corporation
Power Management System:                 Ockerman Automation Consulting, Inc.
600V Switchboard:                                Lloyd Controls, Inc.
480V Switchboard:                               Lloyd Controls, Inc.
Overside Dredge Pump Drives:              Siemens Energy and Automation, Inc.
Bow Thruster:                                      HRP USA, Inc., 1,000 HP

Previous electrical configuration maintained separate ship service and dredging switchboards requiring respective generators to be online in order to supply that switchboard (ex. SSDG’s online to supply 480V). With the Repowered configuration, a bus-tie transformer was installed to allow any generator to feed either switchboard which expanded the various electrical operating scenarios and therefore increased system flexibility, redundancy, and efficiency.