Development of an improved cable trenching plowshare

Cable burial by plowing is the most widely used and reliable method of protecting undersea telecommunications cables from hazards in the ocean environment, including fishing activity, shifting bottom conditions and ships´ anchors. While there is no absolute method for quantifying what level of protection is needed for a particular cable construction project, the trend in soft soils (such as those commonly found in the Far East) is to bury deeper than the one-meter standard. In order to accommodate this new requirement, Tyco-Submarine Systems Ltd. (TSSQ) has developed a new jet-assisted plowshare with improved cable trenching performance. In terrestrial trials, comparing both passive and jet-assisted modes, this new tool, used in conjunction with TSSL´s Sea Plow VIII, demonstrated a 50 percent reduction in tow tension when water was introduced at 1800 gpm and 100 psi discharge pressure. Corresponding increases in speed and penetration were from 1.0 to 2.5 knots and 1.0 to 1.5 meters respectively. Follow-on sea trials verified these performance measures and indicate that with water assistance, cable plowing can be achieved at higher trenching rates and lower tow tension. These improvements should allow deployment of plowing equipment from smaller, less expensive platforms and provide cable construction customers with a cost-efficient alternative for future burial projects