The working pressures in case of jacket water system or lubricating oil system are usually of higher pressure than sea water system. If the leakage takes place in the jacket cooling water side or lubricating oil side, the flow from any point of leakage is in to the sea water side of the cooler. If the leakage is heavy then, usual indication is loss of jacket cooling water or lubricating oil. Procedure: Ensure the end covers are removed from the sea water box side and secure the tube stack by dog clamp arrangement-tube stack should not be disturbed when shell is under pressure. • Clean the sea water side of the cooler. • Start the fresh water cooling pump or lubricating oil pump. • Let the fluid circulate through the cooler spaces on the outside of the tubes. • Leakage within the tubes or at the junction of the tube plate will show up as liquid trickling. • Identify the tube which is leaking. It is a time consuming procedure so be patient. Fluorescent Halo Test Small leaks are extremely
Marine Engineering exam notes for Seafarers