Hull Structural Integrity · Felixstowe, United Kingdom

Structural Inspection of Container Ship Coamings, Lashing Bridges and Hulls at Felixstowe

The structure that matters on a big boxship is not always where a bulk-carrier specialist would look first. Hull structural integrity inspection at Felixstowe records coaming and deck condition, lashing bridge and cell guide damage, corrosion pattern and cracks, with thickness readings alongside. It is carried out at the deep-sea and feeder berths, at Harwich and at Ipswich. A team travels from India on UK visas and works within the cargo window of a ship that sails on schedule and returns on a known rotation.

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Lashing bridges after impact

Container handling damages lashing bridges and cell guides. After reported impact, affected members are gauged and welded connections are cleaned and tested by magnetic particle inspection inside the cargo window.

Coaming corners and deck longitudinals

Hatch coamings and upper-deck longitudinals carry high stress on a large hull. They are checked for wastage and fatigue cracking together, bay by bay, as cranes finish each one.

Ferry decks and Ipswich holds

Ro-ro ferries at Harwich and bulk carriers at Ipswich give longer windows. Vehicle decks, ramps, holds and ballast tanks can be inspected in sequence within the timetable or alongside period.

What structural problems affect container ships at Felixstowe?

A large container ship has big deck openings, so the deck plating, hatch coamings and longitudinals beside them carry much of the hull girder's bending and torsion. Stress is greatest at the corners of the hatch openings, and the welded connections there are a classic place for fatigue cracks to start. Ships on Asia–Europe loops work the hull through heavy weather on every voyage, which adds cycles. A crack at a coaming corner is a structural finding, and its position, length and direction decide whether it is a local repair or a wider concern.

Other damage comes from handling. Lashing bridges and cell guides suffer impact from spreaders and containers, and bent or cracked members show up in the records of ships that have been working hard. Corrosion shows in ballast tanks, on horizontal members and under failing coating, while scrubber casings and overboard lines corrode from the inside on scrubber-fitted ships.

Older feeders on short-sea services show a different profile from the biggest ships. Their ballast tanks are small and heavily worked, their coamings are lighter, and they approach renewal surveys while still trading hard, so a structural inspection at Felixstowe is often the first time anyone has looked at the whole picture since the last docking. The report ranks findings by consequence, so the manager can see which are urgent and which can wait for the docking.

How is inspection fitted into a Felixstowe cargo window?

The team boards through the terminal's ISPS gate and works while cranes are moving, which closes some areas and opens others. Hatch covers and coamings can be reached between crane moves on bays already worked, and engine-room and scrubber piping is unaffected by cargo. Tanks can be entered when the chief officer's ballast plan allows one to be emptied and ventilated without disturbing stability during cargo operations. The ship's officers and the terminal both need to know where the team is at all times.

Because the ship returns on a known rotation, a structural inspection can be divided across consecutive calls. The first call concentrates on the weather deck and coamings; the next can cover tanks or lashing structure, depending on findings. Reference points stay fixed, so cracks found on one visit can be re-examined on the next to see whether they have grown.

Weather matters on this coast. A deck inspection on an exposed upper tier in a strong easterly is slower and less reliable, because wind and spray make cleaning for magnetic particle testing difficult, so the plan carries a fallback: if a bay cannot be tested properly in one call, it is marked and finished on the next rotation, and the record says plainly that it was not completed.

Coamings and deck: between crane moves on bays already worked.
Lashing bridges and cell guides: when the bay is clear of containers.
Tanks: when the ballast plan allows one to be released safely.
Machinery spaces: independent of the cargo plan.

What structural work is possible at Harwich, Ipswich and the anchorage?

Harwich International runs ro-ro ferries to a timetable, so vehicle decks, ramps and the structure around them can be inspected within a known stay. Deck stiffeners, ramp hinges and door frames are the usual targets, with crack detection at hinges and brackets. At Ipswich, bulk carriers loading grain or discharging aggregates lie alongside for several days, and holds, hopper plating, frames and ballast tanks can be inspected in sequence.

Ships queuing for a Felixstowe berth sometimes anchor off the Haven. A launch arranged through the agent can reach them in suitable weather, but the southern North Sea can close that option quickly, so anchorage scopes are short and are called off if the sea state worsens.

Harwich and Ipswich also differ in what can go wrong with time pressure: a ferry cannot be delayed to finish an inspection, so the scope there is always sized to the turnaround, while an Ipswich bulker with several days alongside can be examined at a steadier pace and with more thorough crack detection on holds and frames.

What does a structural inspection at Felixstowe record?

Thickness is measured by ultrasonic gauging and located by frame, strake and member. Pitted plating is described by pit depth and intensity, and grooving or edge corrosion is reported separately from general wastage. Deformation is measured against a straight edge. Cracks are found visually, then confirmed by magnetic particle testing on cleaned steel at coaming corners, brackets and lashing bridge connections.

The people doing the testing are certified within our ASNT SNT-TC-1A written practice, and what they record on cracks is the owner's NDT record. It supports the class engineer's assessment but is not a class approval. Port state control at Felixstowe is the responsibility of the Maritime and Coastguard Agency, applying the Paris MoU regime under UK law, and corroded lashing bridges or leaking overboard lines are findings an inspector can see at once.

Thickness readings with corrosion pattern and deformation record.
Crack detection record with location, length and orientation.
Lashing bridge and cell guide condition notes.
Photographs referenced to bay, frame and member.

How is a Felixstowe structural inspection planned?

Tell us the ship type, age, last survey dates, damage reports and the rotation. We agree the scope with the superintendent and chief officer before arrival, board when the ship is fast alongside and stop when the terminal is ready to sail her. Where the scope is larger than one call allows, the rotation makes it straightforward to finish on the next visit with the same technicians.

The team flies from India into Heathrow, Stansted or London City and travels to Felixstowe by road. Felixstowe, Harwich and Ipswich each run ISPS-controlled gates and the agent requests passes. The technicians come on UK visas, so we work from the liner schedule, book the call we will join early and keep a later rotation in reserve if the first one slips.

Where hull structural integrity sits in the survey cycle

How much steel has to be gauged depends on which survey the ship is due for, its type and its age. The pattern below is the usual one under IACS unified requirements; the attending surveyor and the class rules for the ship decide the final extent. For a ship calling at Felixstowe, we agree the programme with the class and the owner before the team mobilises.

Survey	When it falls	What the thickness measurement usually covers
Annual survey	Every year, within three months of the anniversary date	General examination. Gauging where the surveyor finds suspect areas or where substantial corrosion was recorded at an earlier survey.
Intermediate survey	In place of the second or third annual survey	Suspect areas, and on older ships and ESP ships selected ballast and cargo spaces with close-up survey; the extent grows with age.
Renewal survey No. 1	Around 5 years	The first full baseline: suspect areas and selected plating and stiffeners, usually with modest steel renewal.
Renewal survey No. 2	Around 10 years	Wider gauging of deck, bottom and side plating, transverse sections across the cargo area on ESP ships, and more close-up survey.
Renewal survey No. 3	Around 15 years	Extensive gauging of cargo and ballast tank structure and more transverse sections. The survey most likely to turn up steel renewal.
Renewal survey No. 4 and later	Around 20 and 25 years	Gauging extended to most structural members in cargo and ballast spaces. Charterers often add a Condition Assessment Programme.
Docking survey	Twice in each five-year period	Bottom and side shell, sea chests, rudder and stern area while the hull is dry; suspect bottom plating gauged.

How the job runs at Felixstowe

A gauging job at Felixstowe runs the same way whatever the ship type. The sequence below is what the superintendent, the attending surveyor and the yard can expect from us.

Send the vessel name or IMO number, ship type, class society, the survey due (annual, intermediate, renewal survey number, CAP or owner's condition survey), the port and dates, and the scope you expect.
We confirm the scope against the class rules for that survey, prepare the thickness measurement plan with frame and section references, and say whether the measurement will be credited to a class survey.
Mobilisation is planned around visa lead times and the vessel's schedule; the ship's agent arranges port access, and the yard or ship arranges staging, lighting, ventilation and gas-free certificates.
Gauging with calibrated ultrasonic thickness gauges: through sound coatings only where the gauge's through-coating mode has been verified on a coated reference, otherwise on cleaned bare steel, with every reading tied to its frame, strake and location on the sketch.
Readings are compared with original thicknesses as work proceeds; substantial and excessive corrosion and any cracks are reported to the attending surveyor and the superintendent the same day.
The final report is issued on the class thickness-measurement formats with sketches, a summary of locations exceeding the allowable margins, piping tables where piping was in scope, and the gauge calibration and technician certificates.

Who does the work, and when class approval applies

Atlantis mobilises its inspection team from India to the vessel, for each job. There is no office or agent at the port; the team travels to the ship, which is why the planning step comes first. Work is planned and supervised by our Responsible NDT Level III, the founder, who holds ASNT NDT Level III in UT, RT, MT, PT and VT and has more than eleven years of international field experience. Technicians are qualified and certified under the company's written practice to ASNT SNT-TC-1A, and Atlantis is certified to ISO 9001 and ISO 14001.

Thickness measurement that a classification society credits to a class survey has to be carried out by a firm approved by that society under IACS UR Z17. Atlantis is in the process of obtaining UR Z17 approval from DNV, Lloyd's Register and ABS. Until a certificate is issued, the readings we take are for the owner's own decisions, not for credit to a class survey, so tell us the vessel's class and the survey due when you enquire and we set the scope for the right purpose. Owner's and charterer's condition gauging, pre-docking steel estimates, pre-purchase and on-hire or off-hire gauging, and scrubber and piping condition checks between surveys do not need class approval.

Governing codes and standards

IACS UR Z7 (hull classification surveys)
IACS Common Structural Rules where they apply to the ship type
SOLAS chapter II-1 (structure of ships)
ASTM E797 and ASTM E709 (thickness gauging and magnetic particle testing)
ISO 17638 (magnetic particle testing of welds)
ASNT SNT-TC-1A (personnel qualification under the written practice)

What you receive

Thickness readings by frame, strake and member with diminution against original
Corrosion pattern and deformation record
Crack detection record for coaming corners and lashing bridge connections
Photographs referenced to bay and member
Re-inspection plan for the next rotation

Industries served

Large container ships
Feeder container ships
Ro-ro and freight ferries
Bulk carriers at Ipswich
General cargo ships

Frequently asked questions

Can lashing bridges be inspected at Felixstowe during cargo work?

Yes, on bays that are clear of containers. Members are gauged and welded connections are cleaned and tested by magnetic particle inspection. Because work stops where cranes operate, the sequence follows the cargo plan, and anything unfinished is carried to the ship's next call.

How are hatch coaming cracks found on a large container ship?

Coaming corners and top plates are cleaned locally, examined visually and tested by magnetic particle inspection, with thickness readings taken beside them. The record gives position, length and orientation, so a repair can be planned and the same crack re-examined on the next rotation.

Does a structural inspection at Felixstowe replace a class survey?

No. It gives the owner or manager measured evidence on corrosion, deformation and cracks, which the class engineer can use in assessing the ship. Our crack detection results are owner's NDT records and carry no class credit. Survey credit remains a matter between the owner, the class and the surveyor.

What can be inspected on ferries at Harwich?

Vehicle decks, ramps, hinges, door frames and the structure around them, within the timetable the ferry keeps. We gauge plating, examine stiffeners and test hinges and brackets for cracks. Because the schedule is predictable, the scope can be split across several turnarounds.

Do technicians need UK visas for Felixstowe?

Yes. Felixstowe is in the United Kingdom, outside the Schengen area, so the team travelling from India applies for UK visas. We start once the call is firm, book the call we will join early and hold a later rotation in reserve in case the first one slips.

Can hull structural integrity at Felixstowe be credited to a class survey?

Planning a survey or a drydock?

Send the vessel name or IMO number, the class, the survey due and the port. We reply with the scope, the mobilisation plan and a quote for that vessel.

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Request a ship gauging quote

Send the vessel name or IMO number, the class society, the survey due and the port. We reply with the scope, the mobilisation plan and a quote for that vessel.

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