International Dredging Review

International Dredging Review

King Fisher Marine Services Inc. (KFMS) has purchased five Trimble MS 860 II DGPS heading bundles coupled with five Trimble Marine GPS 132 USCG/OmniStar DGPS correction receivers from Western Data Systems Inc.

KFMS is using the systems to replace existing Sperry Gyro Compasses and older model Trimble 4000 series receivers (which are still operational after nine years of service on the dredges with no down time for GPS hardware.)

The Trimble Marine 132’s track either USCG MSK beacon signals or sub-meter satellite differential corrections from OmniStar and pass this correction information into the MS 860 II unit. The MS 860 II then supplies the Trimble HYDROpro software with a binary GSOF message string that provides extremely accurate DGPS positions (0.03„a with a 10 meter antenna baseline) True North Heading and other QA/QC and status indicators.

Trimble’s HYDROpro Navigation software takes this information coupled with an AGI (Applied Geomechanics) tiltmeter mounted on the ladder and accurately provides XY and Z position of the cutterhead in the form of user-defineable plan profile and textual displays. The tiltmeter is a model MD900-T digital/analog clinometer.

The dredges use HYDROPro’s plan view map which depicts the project and the dredge’s position in it and the profile display which is a view of the channel template showing the position of the cutterhead. Survey text information provides digital readouts of strategic project data such as depth of the ladder position of the ladder and how far the cutter is off centerline among others. For levermen who prefer a visual view of this information the offline bar uses an O in the middle for the center of the channel with cutter position shown to the left or right.

A depth indicator screen shows a scrolling line on the screen that tracks the position of the ladder as it moves up and down.

King Fisher has placed the MS 860 II units on four cutterhead dredges: the Everett Fisher the Leonard Fisher the J.N. Fisher and the Shamrock. The fifth unit purchased will be installed on their new hydrographic survey vessel which is still under construction.

Projects utilizing the MS 860 technology include the Sims Bayou Project on the Houston Ship Channel with the J. N. Fisher. The Shamrock and the Everett Fisher are working in the Gulf Intracoastal Waterway near the Brazos River crossing at Freeport Texas and the Leonard Fisher is working on a Corpus Christi Bay project.

KFMS Inc. of Port Lavaca Texas is part of the Orion Group of companies. Other companies in the group are Orion Construction including Orion/Mid-Gulf and Orion Diving and Salvage of Houston Texas and Inter-Bay Marine Construction of Tampa Florida. The group offers comprehensive marine construction services throughout the world with a customer base of nearly 1000 companies.

Western Data Systems Inc. (WDS) of Houston Texas is a Trimble Navigation re-seller in marine survey and construction and land survey and mapping GPS equipment and software. WDS has an extensive rental equipment inventory of more than 150 GPS receivers software packages computers echo sounders radio modems and other peripheral survey-related items. The company provides complete installation and Trimble certified training on all systems sold.