Underwater Steel Plate Repair Kamsar
Steel plating is the skin of the ship, and any hole, crack or heavy corrosion in it must be dealt with. Underwater steel plate repair in Kamsar uses patches, doublers and, where accepted, insert plates to restore the hull's integrity while the ship remains afloat. The method depends on the size and cause of the damage and on what the class society allows.
Types of Plate Repair
- Soft or box patch: a temporary cover bolted or clamped over a hole to stop water entry quickly.
- Doubler plate: a new steel plate welded over the damaged area, normally accepted as a temporary repair.
- Insert plate: damaged plate is cut out and replaced by a new insert, usually in a dry habitat or cofferdam, and may be accepted as permanent.
- Crack stop and weld repair: stop-drilling and welding of cracks, followed by a doubler if needed.
Assessment and Measurements
The repair starts with cleaning and measuring. The Diver cleans the area to bare steel and takes ultrasonic Thickness Measurement around the damage to find sound plate for welding. The size, shape and extent of the damage are recorded, and a template of the repair plate is made. If the surrounding plate is too thin, the repair area is enlarged.
Materials
The repair plate must match or exceed the grade of the existing steel, for example normal or higher-strength shipbuilding steel, and must be supplied with a mill certificate for class. Welding consumables are approved for underwater use. Bolts, gaskets and sealants for soft patches are marine grade, and anodes are fitted where the repair affects the cathodic protection of the hull.
Fitting and Welding
The plate is lowered to the Diver and fitted tightly over the damage. Small tack welds hold it in place, followed by full welds around the edges, applied in a sequence that limits distortion. For doublers, the welding is carried out around the whole perimeter to form a watertight seal. Where the plate is large, it may be pre-formed to follow the hull curve.
Testing
Repairs are tested to confirm they are watertight and sound. This includes visual inspection, a check from inside the ship for leaks, and, where required, magnetic particle or ultrasonic inspection of welds. For doublers over a hole, the space is checked for water ingress before the ship sails.
Class Acceptance and Follow-Up
Underwater plate repairs normally need class approval and, if temporary, a condition of class with a deadline for permanent repair. We prepare the documentation and photographs, so the surveyor can review the work and the owner can plan the next dry-docking. The report includes plate size, grade, weld details and tests.
Request a Plate Repair Plan
Send photographs, measurements and the class details. We will propose the repair method and timeline.
Why Plate Thickness Records Matter
Thickness readings taken before and after plate repair form a record of the hull's condition. They show how much sound steel is left near the repair, and they help class decide whether the repair is adequate. They also provide a baseline for future inspections. We include thickness tables and a plan marking each reading in the report, so that the next surveyor can repeat the measurements at the same points.
Choosing Doubler Size and Shape
A doubler plate should extend beyond the damaged area to sound steel in all directions, normally with rounded corners to reduce stress concentration. The size depends on the damage and on class advice. We make a template before cutting the plate and check the fit with the Diver. A well-shaped doubler is stronger, easier to weld and more likely to be accepted by class as a temporary repair.
Frequently Asked Questions (FAQ)
Q1. Is a doubler plate a permanent repair?
Usually accepted as temporary, with a condition of class and a deadline for permanent repair at dry dock.
Q2. How is repair plate matched to the hull?
By grade and thickness, with mill certificates provided to class.
Q3. How long does a doubler repair take?
From 1 to 3 days, including preparation, fitting, welding and testing.
Q4. How is watertightness tested?
By inspection from inside the ship, and by checking for ingress after the repair.
Q5. What if surrounding plate is too thin?
The repair area is enlarged to reach sound steel, or another method is chosen.