Incab’s Patented Sealing System for Submarine Cable Cores

At the heart of Incab’s submarine optical cable, available in lengths of up to 50 km, is a patented development. The longitudinal sealing system for the optical core ensures cable reliability at great depths and in the event of accidental damage. The submarine cable core has completed a full cycle of testing on the hydrostatic rig at the Incab Test Centre. The rig can reproduce the pressure a cable experiences at a depth of 4 kilometres — that is, 400 atmospheres. Two scenarios were examined. The first is normal operation: the entire cable held under 400 atmospheres of pressure. The aim is to confirm that the undamaged structure withstands such pressure. The second is a failure scenario: a rupture of the sheath is simulated, and water is fed into the cable through the end face at the same pressure. The aim is to measure how far the water travels along the core. What this delivers If the cable is damaged on the seabed, water does not spread along the entire line — the sealing system halts it within a limited section. In practice this means only a short length needs replacing, while the main part of the line, up to 50 km long, keeps working. Repairs are faster and costs are considerably lower. Why this is a difficult engineering problem Under enormous pressure, water behaves differently than it does in ordinary conditions: it seeks out any micro-gaps inside the core and penetrates them. Stopping it requires understanding exactly how moisture is distributed through the cable structure and where it can be trapped. Incab’s engineers used data from the hydrostatic rig to refine, step by step, a design that withstands these conditions. For all questions about submarine optical cables: mail@incab.ru