Novel Salt-Tolerant Water Blocking Materials for Marine Cables

When the jacket of marine cables has been compromised or breached, seawater will reach the core of the cable and move longitudinally until reaching the equipment they are connected to. To prevent damage to this expensive equipment, water block materials are incorporated during the cable manufacturing process. According to MIL-DTL-915G, fillers for cables that are required to be watertight should be able to fill any voids within the cable. Rubber-like compounds, like the ones traditionally used to manufacture Navy outboard cables, are commonly used as water block fillers. Rubber-based water block compounds are often used in cables due to their high mechanical strength and durability. However, since rubber-like compounds are just a physical barrier, outboard cables that are manufactured with this type of filler do not pass the watertightness – low hydrostatic pressure test at 25 psi per MIL-DTL-915G. To address the Navy’s need for reliable water block compounds, Luna Labs is developing salt-tolerant water-absorbent compounds that absorb enough water to prevent or drastically slow the movement of water inside the cable, reducing the risk of water-related damage and ensuring the reliability of Navy equipment. Luna Labs’ salt-tolerant water-absorbent compounds are being designed to be incorporated into commercial hydrophobic rubber-like materials for easy integration into current cable manufacturing processes and to synergistically work as one system that is effective both at low (25 psi) and high (1000 psi) hydrostatic pressures.