6 June 2002

two pans were found to be plugged with stiff clay. The clay was removed using

pry bars and a high-pressure water hose. Dredging resumed after a downtime of

2 hr 15 min. Both before and after dredging sediment samples indicated the

presence of silty sand in this area. Because the dredge production data collection

system was not yet operational (depth of dustpan in particular), the specific

reason that the dustpan was clogged with clay in this instance is not known. It

could have been possible that the dustpan exceeded project depth and got into

new work (clayey) material. On subsequent pan plugging events with clay,

review of the dustpan x-, y-, z-positioning data indicated that the dustpan was

deeper than project depth or slightly outside the channel toe. This condition

probably placed the dustpan into new work (clayey) material that is not repre-

sentative of the channel's maintenance material (silty sand) in that area.

6 June 2002

Operations continued during the early morning of 6 June with shutdowns

occurring to allow for vessel traffic passage. The Beachbuilder made several

750-ft channel parallel cuts on the RDB side of the channel. While conventional

dustpan dredges typically operate on longer wire cable sets (with respective

impacts on production rates), a 750-ft cut was the optimal length for the

Beachbuilder based on the available wire cable spooled on the winches. The

upstream anchors had to be reset several times because they were dragging

downstream. The dredge was shut down for 20 min to add one section of shore

line in the placement area.

During the morning of 6 June, a meeting was held with Weeks and OAS

personnel to discuss the anchor movement problem. Weeks personnel suggested

that a larger tug with more horsepower would provide additional propulsion

capability to the dredge thus reducing the strain on the anchors. The anchors

would be used for steering and the tug would provide the main thrust for moving

forward into a cut. It was agreed to mobilize a larger tug, the Delta Pacer, and

move the Delta Eagle to the starboard side of the dredge near the bow to increase

the cross-channel maneuverability of the dredge. With the new tug arrangement,

the center forward and two aft anchors could be eliminated. This would provide

much better maneuverability and a faster response time in moving across the

channel. The Delta Pacer arrived at the project site in the late afternoon on 6

June and replaced the Delta Eagle.

On the afternoon of 6 June, the full channel width maneuverability demon-

stration was conducted. The Beachbuilder was moved to the LDB side of the

channel in Reach 1 stretching the floating hose across the channel. Pumping was

initiated on a cut adjacent to the LDB side channel toe. At 1640 hr, a simulated

vessel traffic approach was announced. Pumping was ceased, the ladder raised,

and the Beachbuilder began moving to the RDB side of the channel. The

Beachbuilder was clear of the channel at 1651 hr, a total of 11 min.

During this period, the MVN notified the USACE, OAS, and Weeks Marine

personnel aboard the Beachbuilder that a shoal was building rapidly just

upstream of Reach 1. The MVN decided to mobilize a hopper dredge to this area

and requested that the Beachbuilder cease operations in Reach 1 because the

Chapter 2

Project Description