YSK-DD4-SRF- OVERHAUL CAISSON 4

1. Scope of Work: a. Overhaul caisson. b. Perform UT prior to construction commence. 2. Justification / Reason: a. The existing DD4 caisson was built in 1996 and the last major overhaul was done in 2017 with no continual preventive maintenance. The exterior and interior steel surfaces of the hull, structural members and piping are deteriorated and rusted. Furthermore, all the valve system with auxiliary devices are also deteriorated and rusted. The caisson must be maintained on interval to ensure that the dry dock is safe to operate and in good working order. Caissons are usually overhauled every 10 years and replaced every 60 years.