Ultrasonic Testing Aboard Ship: What It Checks, and How
Coltraco's instruments all do one thing: turn something you can't see, whether a worn seal, a leaking fire cylinder, thinning steel, a flow rate, or a falling gas pressure, into a number you can read and log. This guide explains where each instrument is used, how a crew uses it, and which standard it helps you satisfy.
Sound that reads through steel
Ultrasound, sound above human hearing, travels through metal, liquid and gas in predictable ways, and changes when it meets a boundary. Coltraco's instruments exploit that in different ways: a watertight tester listens for ultrasound leaking through a gap in a seal; a level indicator detects the boundary between liquid agent and gas inside a cylinder; a thickness gauge times echoes bouncing between the two faces of a steel plate; a flow meter times pulses sent with and against the flow in a pipe. In every case the sensor stays on the outside. Nothing is opened, drained or discharged, so the inspection adds no risk and no downtime, and one operator gets a decisive reading in seconds.
Five jobs, five instruments
Each discipline below links to the full product detail and a quote.
Confirm the agent is still in the bottle
Where: any fixed gaseous fire-suppression cylinder, including CO2, FM-200®, NOVEC™ 1230, Halon, FE-13™/FE-25™ and clean agents. For explosive-atmosphere areas (LNG/LPG carriers, oil tankers, offshore platforms, gas and chemical facilities) the ATEX/IECEx Portalevel® IS is used in Zone 1 & 2.
How: place the sensor on the outside of the cylinder wall, calibrate, and read the liquid line in under 30 seconds; an extension rod reaches banked cylinders stacked several deep. The Portasteele® Calculator then converts that level into agent weight in kilograms, temperature-corrected to within 1% of true, so it can be checked against the fill weight stamped on the cylinder. No removal, no weighing, no discharge.
Level indicators →
Find the gap a visual check misses
Where: hatch covers, watertight doors and multi-cable transit (MCT) seals.
How: place the 40 kHz ultrasonic generator inside the closed compartment, then sweep the receiver wand along the seal line from outside. The unit reads in decibels, as a number, or as an Open Hatch Value (%OHV), and a hatch cover is treated as weathertight when its %OHV is below 10%. The PRO lets you photograph the site and plot the exact leak location for repair and re-inspection. SOLAS calls for watertight doors to be inspected at least weekly at sea, and the method supports IACS UR Z17 and DNVGL-CP-0484.
Hatch cover & watertight testing →
Measure the steel that's left, through the paint
Where: hull plating, bulkheads, tanks and pipework, anywhere corrosion or erosion thins steel.
How: a dual-element probe (2.5 and 5.0 MHz) uses a multiple-echo technique that times reflections between the metal faces, so it reports true remaining metal and ignores coatings up to 20 mm thick, with no grinding back to bare steel. Calibrate on the supplied 5 mm test block and log readings for the corrosion record. The instrument is built to BS EN 15317:2013 and meets classification-society requirements.
Thickness gauges →
Meter the flow without cutting the pipe
Where: almost any pipe from DN15 to DN2500, including fuel transfers, loading/unloading, cooling and fire sprinkler lines, and heat networks.
How: measure the pipe, apply couplant, and clamp a pair of transit-time sensors to the outside, clear of bends and valves. The meter times a pulse sent with the flow against one sent against it and derives the flow rate to ±0.5%. Use the portable Portasonic® for surveys and commissioning, or the fixed Permaflow® for continuous 24/7 monitoring with alerts. (Transit-time suits clean liquids; particle-laden flow uses the Doppler method.) No drilling, no downtime, no pressure loss.
Flow meters →
The check a level indicator can't do
Where: inert and compressed-gas fire-suppression cylinders, such as Inergen®, nitrogen, oxygen and argon, typically seamless bottles at 100–200 bar.
How: inert gases stay gaseous, so there is no liquid line to read; Portagas® instead detects changes in internal pressure from a known baseline and corrects for temperature, catching a slow loss long before it reaches the 5–10% thresholds cited in NFPA 2001 and ISO 14520.
Gas pressure →Which instrument satisfies which requirement
The regulations a surveyor or port-state inspector works to, and the Coltraco instrument that produces the evidence.
| Standard / requirement | What it asks for | Instrument |
|---|---|---|
| IMO SOLAS Reg II-1/21.3 | Watertight doors maintained and inspected (at least weekly at sea) | Portascanner WATERTIGHT |
| IACS UR Z17 · DNVGL-CP-0484 | Hatch-cover weathertightness by the Open Hatch Value (%OHV) method | Portascanner WATERTIGHT |
| IACS UR Z28 | Survey of multi-cable transits (MCTs): all transits examined and the Register maintained (vessels contracted after 1 Jul 2021) | Portascanner WATERTIGHT |
| IMO SOLAS FSS Code, Ch.5 (§2.1.1.3) | Verify fixed-gas agent quantity without moving cylinders from position | Portalevel + Portasteele |
| IMO MSC.1/Circ.1318/Rev.1 | Confirm fixed-gas cylinders hold at least 90% of nominal charge, at least every 2 years | Portalevel + Portasteele |
| NFPA 2001 · ISO 14520 | Gaseous agent / pressure loss kept within the 5–10% threshold | Portalevel (liquefied) · Portagas (inert) |
| BS EN 15317:2013 | Characterisation & verification of ultrasonic thickness equipment | Portagauge 6 |
| Class survey (ABS / RINA / etc.) | Structural thickness & corrosion records through coatings | Portagauge 6 |
Standards and approvals as cited by Coltraco Ultrasonics. Confirm the current applicable revision and your vessel's specific requirements with your class society.
The terms, plainly
- Non-invasive
- The sensor sits on the outside surface; nothing is opened, drained, weighed or discharged to take the reading.
- Open Hatch Value (%OHV)
- The Portascanner's measure of how much ultrasound passes through a hatch seal. Below 10% the cover is treated as weathertight.
- Multiple-echo
- A thickness technique that times reflections between the two metal faces, so it reports true steel thickness and ignores paint/coating.
- Intrinsically safe / ATEX Zone 1 & 2
- Certification allowing an instrument to be used in explosive gas atmospheres without a Hot Work Permit; this is the Portalevel IS rating.
- Banked cylinders
- Fire-suppression cylinders stored in rows several deep; reached with the Portalevel extension rod.
- Transit-time vs Doppler
- Two ultrasonic flow methods: transit-time for clean liquids (Portasonic/Permaflow); Doppler for particle-laden or aerated flow.
- Couplant
- A gel applied between sensor and surface so ultrasound passes into the material instead of reflecting off the air gap.
- Multi-cable transit (MCT)
- A sealed penetration where many cables pass through a bulkhead, a common watertight-integrity weak point that the Portascanner checks.
- Agent weight
- The mass of suppression agent in a cylinder: the figure regulations ask for, derived from a level reading by the Portasteele Calculator.
- Clean agent
- An electrically non-conductive, residue-free gaseous fire-suppression agent such as NOVEC 1230 or FM-200.
Common questions
Why use ultrasonic testing instead of opening, weighing or flooding?
Can one crew member carry out these checks?
Are ultrasonic readings accepted for class and port-state requirements?
Which Coltraco instrument do I need for which job?
Can I order Coltraco instruments through ShipServ?
Tell us the vessel and the survey
We'll spec the right Coltraco configuration, note the approvals, and quote it, through ShipServ or direct.