Maritime inspection · Montenegro
Yacht Hull Thickness Gauging in Tivat, Bay of Kotor
Tivat sits in the outer part of the Bay of Kotor and is built around a superyacht marina on the site of a former naval arsenal, with a large yacht repair and refit business beside it. Steel and aluminium yachts come for winter work, and a smaller flow of workboats and passenger craft uses the bay. Atlantis NDT sends ultrasonic technicians from India for gauging jobs, with nobody permanently stationed in Montenegro.
Superyacht refit on a former arsenal
The marina and yard area at Tivat occupy a historic naval site, and large yachts come here for winter maintenance. Hull plating and tank boundaries are gauged once the yacht is lifted or while it stands in a work berth.
Steel and aluminium hulls
Large yachts mix steel hulls with aluminium superstructures, so gauging means two calibrations and a plan for the joints, where dissimilar metals corrode and where plating records are most useful to the surveyor and the captain.
Pre-purchase checks for buyers
Yacht sales are common in the bay. A buyer's surveyor wants measured plating, tank and rudder-stock data on a yacht before a deal closes, and gauging can be carried out on the day the yacht is hauled.
Inspection services for ships at Tivat
Each service has its own page with the method, the class requirements and what the report contains.
Ultrasonic Thickness Measurement (UTM)
Hull, tank, deck and bulkhead gauging recorded on the class thickness-measurement formats, with sketches and corrosion flagged against the allowable margins.
ExploreSpecial Survey Thickness Measurement
Gauging for the 5, 10, 15, 20 and 25-year special (renewal) surveys and intermediate surveys, plus pre-docking steel estimates.
ExploreCAS (Condition Assessment Scheme)
Thickness measurement and survey support for the IMO Condition Assessment Scheme, and what CAS asks of an older tanker today.
ExploreCAP Thickness Measurement
Gauging and close-up survey data for a Condition Assessment Programme, the voluntary class service charterers ask for on older tankers and bulk carriers.
ExploreESP Gauging
Thickness measurement and close-up survey support for oil tankers, chemical tankers and bulk carriers under the ESP Code.
ExploreHull Structural Integrity
Substantial and excessive corrosion, pitting, grooving, buckling and fatigue cracks, with magnetic particle and penetrant crack detection.
ExploreShip Piping Inspection
Wall-thickness gauging of cargo, ballast, fuel, sea-water and fire-main piping, with minimum-wall checks and isometric sketches.
ExploreScrubber Piping Inspection
EGCS wash-water and overboard discharge piping, the hull penetration area and scrubber welds, checked between dockings.
ExploreIHM (Inventory of Hazardous Materials)
IHM Part I surveys, sampling and maintenance for the EU Ship Recycling Regulation and the Hong Kong Convention.
ExploreMarine NDT Services
Every NDT method we use on ships, from visual inspection and MPI to PAUT and ACFM, chosen by the defect you are looking for.
ExploreTivat, the marina and the outer Bay of Kotor
Tivat is the first sizeable town a ship reaches after entering the Bay of Kotor between the Luštica peninsula and Herceg Novi, on the outer side of the Verige strait. The water here is deep and sheltered, and the bay's mountain backdrop lowers swell to almost nothing. The old Austro-Hungarian and later Yugoslav naval arsenal stood on the waterfront for more than a century, and its docks and quays have been redeveloped as a marina and residential quarter that now serves as a base for superyachts and a shipyard for their refit.
Traffic in Tivat is dominated by yachts rather than merchant ships. Superyachts arrive in the cooler months for maintenance and in spring for charter preparation, and the marina's technical area handles lifting, blasting, painting and engineering work. Between jobs the yachts stay on berths along the quay, where hull and tank condition can be assessed without waiting for a lift. A smaller flow of coastal passenger ships, workboats, pilot boats and small cruise vessels uses the commercial quays elsewhere in the town, and Tivat's airport brings crew and owners in directly.
For gauging, yachts pose different problems from cargo ships. Plating tends to be thinner relative to span, coatings are multi-layered and expensive to strip, and access to tanks is through small openings. Records are asked for by captains, owners' representatives and class surveyors alike, and a pre-purchase condition survey must be finished within the days a buyer's surveyor is on site. A clear plan agreed with the yacht's technical manager before arrival, naming plating panels, tank groups, sea chests and rudder areas, is what keeps each job inside the time available.
Where gauging happens around Tivat
The principal gauging place is the marina's repair and refit area. When a yacht is hauled and the hull is dry, the plating, keel, rudder and propulsion appendages can be gauged from the ground or from staging, usually after the old coating has been removed and before new primer goes on. Tank boundaries are measured from inside once the tanks are cleaned and certified. The yard controls access, hot work and lifting, so the technical manager agrees the programme with the yard in advance.
Yachts that are afloat can also be worked on. Alongside in the marina, internal tanks, engine-room bulkheads, deck plating and sea water systems can be gauged without lifting, which makes it practical for pre-purchase checks and for mid-season inspection ahead of a refit decision. For larger commercial ships the bay offers no drydock at Tivat, and owners use the shipyard at Bijela, also in the bay, or yards on the Adriatic coast. Readings taken at Tivat feed those yards' steel estimates.
- Marina refit and repair area: hull plating, keel, rudder and appendage gauging with the yacht hauled and the hull dry
- Yacht work berths on the quay: tank boundary, engine-room bulkhead and deck plating gauging afloat
- Marina berths for sale surveys: plating and tank readings for a buyer's surveyor during the days of a pre-purchase inspection
- Commercial quays of the town: workboats, pilot boats and small passenger vessels gauged alongside
- Outer-bay anchorage: launch-borne condition checks on larger yachts awaiting a berth
Thickness measurement through the survey cycle at Tivat
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 Tivat, 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. |
Regulation, flag and class practice for yachts in Tivat
Large yachts are mostly regulated through their flag and class rather than through port state control in the way merchant ships are. Many carry class from an IACS society and operate under the code for large commercial yachts, with periodic surveys and thickness records kept in the ship's file. Montenegro is a Paris MoU member and the Maritime Safety Administration is the national authority, but yachts used purely for pleasure have different obligations from cargo ships. Gauging records are nonetheless requested by flag state surveyors and insurers before refit schedules are agreed.
Montenegro is outside the EU, but yachts moving between Tivat and EU ports meet EU rules on the other side, and many are managed from Italy, France or Monaco. Where a yacht holds class, thickness measurements credited to a class survey must be taken by a firm acceptable to that society, so the technical manager should settle this at the planning stage; gauging for owner's decision-making, refit estimates and sales does not carry that requirement. Entry rules for visiting technicians in Montenegro are national and are checked at the start of each job.
Since 1 May 2025 the whole Mediterranean has been a sulphur emission control area, so ships calling at Tivat burn 0.10% sulphur fuel or run a scrubber. Scrubber wash-water piping, the overboard discharge and the hull penetration around it corrode quickly in service and are worth adding to the gauging scope at every docking.
Typical thickness gauging jobs at Tivat
Tivat work comes in two forms: planned winter refits that take weeks, and short sales or inspection jobs that must be done in a day or two. Both depend on the technical manager's agreement with the yard on access, coating removal and tank cleaning. We settle plating panels, tanks and reporting format in advance, and confirm Montenegrin entry requirements before the technicians travel from India.
- Full hull plating gauging on a steel superyacht hauled for its refit, taken after coating removal and before repainting
- Tank boundary and double-bottom readings on a large yacht with tanks cleaned and gas-free for entry
- Pre-purchase gauging for a buyer's surveyor on a yacht alongside the marina quay, covering plating, rudder stock area and sea chests
- Aluminium superstructure and hull joint readings on a yacht with mixed-metal construction, taken with the gauge set up for the alloy
- Mid-season condition check on a charter yacht to decide the scope of the winter refit before the yard slot is booked
How a thickness measurement job runs at Tivat
Most of the work on a Tivat job happens before the team boards: scope, plan and access are settled first, so the time on board goes on measurement.
Tivat Airport is a few minutes from the marina and has seasonal European flights, which makes it the natural arrival point, with Dubrovnik and Podgorica as alternatives by road. Marina security and the yard issue site passes, usually through the yacht's captain or the technical manager, and no commercial ship's agent is involved for yacht work. Because Montenegro sets its own visa rules for Indian citizens, we check them when the enquiry arrives and plan the mobilisation around the lead time.
- 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
The inspection team is mobilised from India for each job; nobody is stationed at the port, so mobilisation is planned against the vessel's schedule and visa lead times. Our founder and Responsible NDT Level III, who holds ASNT NDT Level III in UT, RT, MT, PT and VT and has over eleven years of international field experience, plans and supervises the work. Technicians are certified under the company's written practice to ASNT SNT-TC-1A, and the company holds ISO 9001 and ISO 14001 certification.
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 UR Z10.1 to Z10.5 (oil tankers, bulk carriers, chemical tankers, double-hull and double-skin ships)
- IACS UR Z17 approval of service suppliers
- SOLAS chapter XI-1 regulation 2 and the 2011 ESP Code
- MARPOL Annex VI regulation 14 and the 2021 EGCS Guidelines (MEPC.340(77))
- The rules of the vessel's classification society
What you receive
- Thickness measurement report on the class formats, with sketches
- Summary of substantial and excessive corrosion against allowable margins
- Pitting and grooving records with depth and extent
- Piping wall-thickness tables with isometric sketches
- Magnetic particle or penetrant crack-detection reports
- Gauge calibration records and technician certificates
Industries served
- Steel superyachts
- Aluminium and composite yachts with steel components
- Charter yachts
- Pilot boats and workboats
- Small coastal passenger ships
- Tugs and harbour craft
- Small cruise vessels
Frequently asked questions
Can you gauge a yacht before the hull is lifted?
Yes, internal structure, tank boundaries, deck plating and some hull areas can be gauged afloat. For full external plating you need the yacht out of the water and the coating removed. We usually recommend a two-stage plan: afloat readings for a pre-refit estimate, then the full hull programme once the yacht is hauled.
Do you measure aluminium as well as steel on yachts?
Yes. Ultrasonic gauges are calibrated for the alloy on a matching reference block, and readings on aluminium are most useful at joints, around fittings and in bilge areas. We agree measurement locations with the technical manager and the surveyor beforehand so the results are comparable at the next survey.
Can gauging be completed within a short pre-purchase window?
Usually, if the scope is agreed before arrival and the yard has tanks open and cleaned. A defined list of plating panels, tank groups and sea chests lets the technicians work through readings in the days a buyer's surveyor is on site. The report is structured so the surveyor can append it to the pre-purchase file.
Is class involvement required for yacht gauging in Tivat?
Only when the readings are to be credited to a class survey. In that case the thickness measurement firm must be acceptable to the yacht's class society. For refit estimates, sales and the owner's own planning, no class involvement is needed, and the technical manager decides how the data will be used.
Does thickness measurement at Tivat need class approval?
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.
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.
Request a QuoteRequest 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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