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Cutting is often the first step of a repair. A damaged plate has to be removed before a new one goes on. A bent fitting must be cut away before a replacement is made. A rope wound tightly around a shaft may need to be cut free. Underwater ship cutting services in Nagoya cover all these tasks.
When a plate is buckled or cracked beyond repair, the damaged area is cut out, usually along a marked line chosen with the surveyor. The Diver uses an oxy-arc or exothermic cutting tool, working slowly to avoid damage to the plating around it. The edges are then cleaned and prepared for the new plate or insert. A plan and a thickness check come first, so the cut is made in sound steel.
Pad eyes, fairleads, bent guards, projecting bolts and broken anodes can be cut off the Hull. The Diver cuts the weld or the piece itself, removes it and dresses the surface. Where something has bent against the ship, such as a bilge keel end or a steel fender, we cut it clear without touching the shell plating more than necessary.
Cutting here is often by knife, hook cutter or hydraulic cutter rather than torch. Heavy wire rope and chain may need hydraulic shears. The Diver cuts and removes the material in pieces and brings it to the surface so that it does not fall back into the water and cause problems. The propeller and the shaft are checked afterwards for damage.
Sometimes a ship picks up steel pieces, cables or timber. Cutting can free the Hull from these without delay. Large debris near the propeller or the sea chest is cut into manageable pieces and lifted out. We always inspect the Hull afterwards to look for damage.
Hot cutting in water requires the same care as welding. Gas pockets must be vented, electrical safety must be followed and the area behind the plate must be safe. Tanks must be gas-free. A hot work permit is issued by the master. For non-hot methods, such as hydraulic shears, the risk is lower, but the propeller, thrusters and pumps must still be isolated.
Send the ship's name, the location and a description of what must be cut. Photographs help. We inspect first, produce a plan and carry out the job in the agreed window. The report includes video of the work and a note of what was removed.
Where plating has been cut out, the repair that follows may be a patch, an insert plate or a dry-dock job. We can carry out the next step if it suits the owner and the surveyor, or hand over the findings so a shipyard can finish the work.
The best tool depends on the job. A hook knife is ideal for rope and light wire. Hydraulic shears are quiet and safe for steel bars and thin plates, with no heat and no gas. Oxy-arc and exothermic torches cut thick steel quickly but need hot work controls. We choose the method after the inspection and explain our choice in the plan, so the owner and surveyor see why.
Cut pieces are removed from the water and not left on the bottom. We collect small parts and debris with baskets and lift them to the surface. If any oil or material is released, we stop and report it at once.
Q1. What tools are used for cutting steel underwater?
Oxy-arc torches, exothermic cutting rods, hydraulic shears, saws and abrasive wheels. The choice depends on thickness, shape and safety conditions.
Q2. Is cutting always done with a torch?
No. Ropes, nets and thin fittings are cut with knives, hook cutters or hydraulic cutters. Torches are used on steel.
Q3. What must be checked behind a plate before hot cutting?
That any tank or void behind the plate is gas-free and certified, and that no gas can be trapped by the cut.
Q4. What happens after a damaged plate is cut out?
The repair can be a patch, an insert plate or a dry-dock job. We carry out the next step if it suits the owner and the surveyor.
