Project Title: Submergence Plane Oil Containment Technology
Principal Investigator(s): M. Robinson Swift and Barbaros Celikkol

Accomplishments
Scheduled Tasks:
One important task was replacing the heavy, rigid end longitudinals on the 40 ft Bay Defender II (BD II) flexible barrier with compliant, lightweight ends similar to those used on the more recent 100 ft Bay Defender III (BD III) design. It was apparent from the previous May 24, 2001 exercise at Adams Point that this would significantly improve launching and recovery of the system from the Piscataqua River Cooperative (PRC) flat-top barge. Both systems are valuable since the two sizes are complementary Ð each balancing ease of handling and transport versus slick interception width in different ways. In addition, the PRC presently has a barge suitable for BD II transport and deployment but does not yet have an equivalent vessel for the larger BD III.

Because the submergence plane, gap and aft barrier meet at the ends at different angles in the two designs, a complete re-design development effort had to be initiated. Scheduled tasks included tank testing with a physical scale model, design, fabrication and field testing.

Though the 100 ft BD III design had been successfully deployed on May 8, 2001 near the Sprague-Newington terminal, demonstration of its capabilities again at another location was planned for this last 6-month period of the project. The intent was to conduct the deployment at a location important to the oil response program of the PRC and the New Hampshire Department of Environmental Services (NH DES).

The information dissemination task is an ongoing one implying the publication of results and working with potential users of this technology. This last effort is critical to the transition of the developed submergence plane systems to practical, commercial usage. Since refereed papers had already been presented at two conferences, our intent was to also complete publication of an article in a refereed journal. Contact had already been made with the James River Reserve Fleet (JRRF) and the New Jersey (NJ) inlets program regarding the use of submergence plane technology to address their fast-water problems. To follow up, we would invite them to attend this year's field exercises.

Progress on Tasks
Work on developing new "soft" ends for the 40 ft BDII began with tank testing design concepts based on what was learned in the previous 100 ft BD III design effort. A 1/5 scale physical model was tank-tested to evaluate and validate trial end configurations (see Figure 1). An optimum shape was identified, and full-time shop drawings were prepared. The new ends were an add-on to the existing main body of BD II and are interchangeable with the present rigid ones. Arrangements were made with JPS Industries, Inc of Bristol, NH for assistance with fabric and end flotation work.

The 40 ft BD II was field tested during flood tide in the Upper Piscataqua on June 13, 2002. The objective was to demonstrate the ability to intercept a slick where the power lines cross, thereby protecting the Cocheco and Salmon Falls rivers. Maximum flood tide current was measured previously on April 30, 2002 to be 1.6 knots which is beyond the critical velocity for ordinary oil boom but within the operating range of flexible, submergence plane systems. The system was deployed from the PRCÕs flat-top barge as shown in Figure 2. One hundred foot lengths of ordinary oil boom were used as lead-ins to increase swath width, while BD II occupied the critical apex position (see Figures 3 and 4). The new ends performed as designed and were much easier to handle compared to the previous rigid design.

Members of the PRC, NH DES, U.S. Coast Guard, and Dover Police were on hand to participate and observe. The JRRF also sent a representative, Calvin Ferguson, who took pictures and video for their organization. Though invited, no one from the NJ inlet program was able to make the trip, so a summary of the exercise with pictures was sent to Rob Schrader of the NJ Department of Environmental Protection, Bureau of Emergency Response.

The 100 ft BD III was deployed at Furber Strait, towards the Great Bay side of Adams Point, on July 25, 2002 during the flood tide. The choice of location was based on determining whether it is feasible to protect Great Bay by intercepting spills where the width between shores narrows. From previous measurements, flood tide current was expected to peak at 1.8 knots Ð considerably beyond the capability of conventional boom but just within the upper limit of 2 knots for flexible, submergence plane barriers. The system was assembled from its component parts the day before during low water along the shore near the Adams Point boat ramp (see Figure 5). (Pre-assembly, of course, is recommended when employed for actual oil spill emergencies.) At high water, the system was towed by a 19 ft Carolina skiff, as shown in Figure 6, to the Jackson Estuarine Laboratory (JEL) mooring where it remained overnight. JEL personnel set a light anchor later to keep the system from swinging into the nearby cove.

At the start of the flood tide the next morning, two 100 ft lengths of conventional boom lead-ins were attached, and the system was towed into Furber Strait. The east lead-in boom was secured to a pre-set anchor. The west end was attached to a rope-anchor-crown line configuration for setting "on the fly". Though 200 ft of anchor line was used in a water depth of 15 ft employing a 55 lb. Fortress anchor, the anchor would not bite. Repeated attempt were not successful. It was obvious that the bottom at that location was unsuitable for an embedment-type anchor.

Since the main thrust of the exercise was the performance of BD III, one of the tow boats played the role of an anchor by holding one of the lead-ins in position, while the other side of the apex was anchored. BD III itself performed well at the apex of the containment configuration as seen in Figure 7. Rice husks were spread as an oil substitute. Husks captured in the containment region, along with many floating eel grass remnants, are shown in Figure 8. The conclusion was that BD III will function as designed for this application, but anchors must be pre-set or heavy, permanent deadweight anchors used.

With regard to publication, the manuscript describing oil retention effectiveness of flexible, submergence plane barriers was published in the Journal of Marine Environmental Engineering, Volume 6, Number 4, pages 257-273. This task was important for legitimizing the science behind the concept and thereby gaining acceptance by the industry.

Difficulties Encountered
The main difficulty encountered was the need for additional personnel during deployments. Assembly, handling, recovery, disassembly, transport, cleaning and storage consumed many hours of physical labor. This project was fortunate that other Ocean Engineering graduate students and staff were willing to pitch in and help out. The participation in all phases by Steve Root of Portsmouth Tow and the PRC made a huge contribution. Dave Shay and Deb Lambert of the JEL were also very welcoming, and their work in looking after BD III in our absence is very much appreciated.

Anticipated Success in Meeting Project Objectives in Scheduled Project Period
Project research tasks are now complete meeting the August 2002 end of project deadline.

Preliminary Results
Based on field deployments and tank-testing, the 100 foot BD III and the smaller 40 ft BD II with new ends work well in fast currents beyond the capabilities of conventional boom.

Tasks and activities for next reporting period

Tasks for the next reporting period
The last project task is the writing of the final report due November 29, 2002.

Work plan to accomplish tasks
Project rationale, methods, results and conclusions will be summarized in the final report.

Concerns or difficulties
None anticipated at this time.

Expenditures
No additional funds, beyond the original budget, have been requested.