Welding & Steel Work

Ship welding and steel work repairs

Ship welding and steel work covers the cropping and renewal of wasted or damaged plating, stiffeners and brackets, crack repairs, doubler removal, pipe and fitting repairs, and the fabrication of small structures such as walkways, ladders, guard rails and foundations. Much of this work is carried out afloat during port stays, often to close a class recommendation, a port state control deficiency or damage from cargo operations or contact.

Because structural welds carry hull loads and can compromise watertight or fire integrity, the quality of the work matters as much as the speed. vslSafety arranges repair contractors with qualified welders, fitters and supervisors who work to class-accepted procedures, together with the gas-freeing, hot-work control and non-destructive testing that the surveyor will expect to see.

Regulatory requirements and standards

Repairs to hull structure on a classed ship are governed by the class society’s rules. Structural repairs should be agreed in advance with class, carried out to an approved repair specification and inspected by the attending surveyor. SOLAS regulation I/11 requires that defects affecting the safety of the ship are reported to the Administration or its recognised organisation, which in practice means class is involved before significant structural work begins.

IACS Recommendation 47, the Shipbuilding and Repair Quality Standard, sets out widely used workmanship tolerances and repair practices for hull structures in normal and higher strength steel, including insert sizes, weld preparation and alignment. IACS UR W28 covers welding procedure qualification tests for hull structural steels, and UR W32 provides a qualification scheme for welders of hull structural steels, with certificates endorsed by the class society. Many repairers also hold welder qualifications to ISO 9606-1. IACS Recommendation 20 gives guidance on non-destructive testing of hull steel welds. Materials used for structural repairs should be of equivalent grade with mill certificates acceptable to class.

Hot work on board must be controlled under the ship’s safety management system with a permit to work, gas testing and fire watch. For tankers, ISGOTT sets additional expectations for gas freeing before hot work. Port authorities and terminals commonly impose their own hot-work permits and may prohibit hot work at certain berths entirely.

Typical requirements and timing

Item	Requirement	Timing	Reference
Structural repair	Repair specification agreed with class, surveyor attendance	Before and after repair	Class rules; SOLAS I/11
Welders	Valid qualification for process, position and thickness	Checked before work starts	IACS UR W32; ISO 9606-1
Welding procedure	Qualified procedure for material and joint	Before production welding	IACS UR W28; class rules
Hot work	Permit, gas test, fire watch, adjacent spaces checked	Every shift and after interruptions	Company SMS; ISGOTT for tankers; port rules
Weld inspection	Visual plus MT, PT, UT or RT as agreed	After welding and cooling	IACS Rec. 20; class rules

What the service includes

• Site survey, measurements and a written repair method statement for owner and class review
• Supply of class-certified steel plate, sections and consumables with material certificates
• Cropping and renewal of wasted plating, frames, brackets and stiffeners
• Crack repair by gouging, grinding out and re-welding, with crack-arrest measures where specified
• Pipe repairs and spool fabrication for ballast, bilge, fire main and deck lines
• Repairs to hatch coamings, ladders, railings, vent heads, air pipes and closing appliances
• Hot-work permits, gas-freeing coordination, fire watch and fire-fighting equipment at the work site
• Non-destructive testing, hose or chalk tests for tightness and coating touch-up after repair
• As-repaired sketches, photographs and documentation for the class surveyor

Work types commonly requested

Typical afloat jobs include ballast tank and hold frame renewals on bulk carriers, cargo damage repairs to hatch covers and coamings, deck plating inserts around fittings, repairs to mooring bitts and fairlead foundations, sea chest and overboard pipe renewals, crane pedestal attachments, and fabrication of new walkways and platforms. Where steel thickness is in doubt, ultrasonic thickness measurement should be completed first so the repair extent is based on recorded data rather than visual judgement. Weld inspection is often arranged alongside non-destructive testing (NDT).

Common defects and PSC deficiencies

• Wasted or holed ventilator and air pipe heads, coamings and closing appliances affecting weathertightness
• Corroded or damaged guard rails, ladders and walkways presenting a personnel hazard
• Temporary repairs such as cement boxes or clamps left in place without class acceptance
• Cracks at hatch coaming brackets, frame ends and stiffener terminations
• Poor-quality previous repairs with undercut, porosity, misalignment or undersized fillet welds
• Hot work carried out without a permit, gas test or fire watch, noted during ISM audits and PSC inspections

Certificates and documents you receive

A complete repair package normally includes the method statement, welder qualification certificates, welding procedure references, steel and consumable certificates, hot-work permits and gas-free certificates, NDT reports signed by a qualified technician, photographs before, during and after repair, and a completion report. Where class attended, the surveyor records the repair in the class records and may delete a condition of class or recommendation.

How to prepare the vessel

Inform class early and agree the repair scope, especially where structural members are affected. Clean, ventilate and gas-free the space, and check adjacent tanks and compartments for flammable contents before hot work. Remove insulation, cargo residues and loose equipment around the work area. Confirm with the agent and terminal whether hot work is permitted at the berth, and whether a marine chemist or port gas-free certificate is required. Provide power, lighting and safe access or arrange staging through equipment rental services.

Information needed for a quotation

• Vessel name, IMO number, flag, class and ship type
• Port or anchorage, ETA, ETD and expected time available for work
• Location and description of the damage, with photographs and sketches
• Thickness gauging results, class recommendations or PSC deficiency wording
• Approximate steel weight or plate sizes, and material grade
• Whether hot work is permitted at the berth, and cargo status of adjacent spaces
• Required NDT, coating and class attendance

vslSafety coordinates a suitable repair contractor at the vessel’s port and returns a scoped quotation for owner approval before any work starts.

Frequently asked questions

Does class need to approve welding repairs?

Repairs to hull structure, watertight boundaries and items covered by class should be agreed with the class society and inspected by a surveyor. Minor non-structural work such as handrails or small fittings may not need attendance, but it is good practice to inform class if there is any doubt. Structural repairs carried out without class involvement may not be accepted and can lead to a condition of class.

What qualifications should ship repair welders hold?

Welders on structural repairs should hold a valid qualification covering the welding process, position, material and thickness range being used, typically under IACS UR W32 or ISO 9606-1 with a certificate endorsed or accepted by class. The contractor should also have a qualified welding procedure for the joint. Ask to see the certificates before the work begins so the surveyor is not presented with a problem afterwards.

Can hot work be done alongside a terminal?

It depends on the port, terminal, cargo and ship type. Many oil and chemical terminals prohibit hot work entirely, while general cargo berths may permit it with a port permit and fire precautions. Tankers usually need spaces gas-freed and certified before hot work. The local agent should confirm the rules in advance, since an unexpected refusal can waste the whole port stay.

Is a doubler plate an acceptable permanent repair?

Doublers are generally regarded as temporary repairs on primary structure and on plating subject to corrosion, and class will usually impose a condition to replace them with an insert by a set date. In some limited locations a doubler may be accepted as permanent, but that decision rests with the class society. Planning an insert from the start usually avoids repeating the job.