Ultrasonic Leak Detector

When a faulty seal on a cargo hatch cover, watertight door, or offshore compartment goes undetected, the damage that follows is costly — flooded cargo holds, water-damaged commodities, failed Classification Society inspections, and vessel downtime. Visual checks cannot find hairline seal failures. Water hose tests are slow, messy, and impossible with cargo already loaded. What professionals across the marine, offshore, and industrial sectors rely on instead is ultrasonic leak detection equipment that finds the exact location of a seal failure quickly, cleanly, and without disturbing operations.

Cygnus Instruments manufactures the Cygnus Hatch Sure — a Class Approved, ABS Type Approved ultrasonic leak detector designed for use in the toughest real-world conditions. At just 3.8 kg, IP65-rated, and operable by a single person, it is the trusted air leak detection system used by marine surveyors, P&I clubs, offshore platform engineers, and ship operators worldwide. Every product on this page is designed and manufactured by Cygnus Instruments under ISO 9001 quality management.

Cygnus Hatch Sure — Ultrasonic Leak Detector

The Cygnus Hatch Sure is a portable ultrasonic leak detector built to locate leaks and identify seal failures in any closing appliance or sealed compartment. On marine vessels it is used to test watertight doors, cargo hatch covers, and weather deck openings. On offshore oil and gas platforms it verifies the integrity of access panels, pressurised compartments, and closing appliances. Beyond marine and offshore applications, the same equipment is used to test door seals on transportation vehicles, structural windows, and any enclosed space where a confirmed airtight or weathertight seal is required.

The system works by placing the transmitter inside the compartment under test. The transmitter carries 19 ultrasonic emitters operating at 40 kHz and distributes an omni-directional sound field that uniformly fills the enclosed space. Outside the compartment, the operator scans along seals and joints using the flexible inspection microphone connected to the handheld receiver. Where a seal has failed, ultrasound leaks through and the receiver detects it in real time — displaying the signal level on its digital screen and delivering an audible tone through the neckband headphones. The operator then slows down, homes in, and pinpoints the exact location of the defect.

What makes the result meaningful is the Open Hatch calibration method. Before the survey begins, the hatch or door is partially opened and the receiver is calibrated against the signal measured through that open gap — this becomes the 100% Open Hatch reference. From that point, every reading is expressed as a percentage of a fully open seal. The standard is clear and objective: any leak reading above 10% Open Hatch means the seal is not weathertight, regardless of who is conducting the survey or which vessel is being tested.

Receiver

The receiver measures 110 × 185 × 45 mm and weighs 500 g including batteries, making it light enough to wear continuously without fatigue. It is powered by a 9 V PP3 rechargeable MaxE battery that provides 4 to 5 hours of continuous operation per charge, or 8 to 9 hours when an alkaline battery is used instead. The unit carries an IP65 weatherproof rating, rising to IP66 when housed in its outdoor all-weather soft-pouch — meaning it operates reliably in rain, spray, and the kind of exposed deck conditions that cause lesser instruments to fail. The ABS plastic enclosure is fitted with an orange shock-absorbing outer boot for protection during the rough handling that comes with shipboard use. The receiver operates between −20°C and +50°C, covering everything from frozen bulk carrier decks in winter to hot engine room access checks. It carries a 3-year manufacturer’s warranty.

Transmitter

The transmitter measures 120 × 150 × 90 mm and weighs 680 g with batteries fitted. Its 19 ultrasonic emitters, each 16 mm in diameter, produce a maximum output of 130 dB SPL at 40 kHz. Rather than a fixed output, the transmitter offers 6 selectable pre-set power levels — full power at 130 dB and five lower outputs descending in 11 dB steps down to 75 dB. This range matters in practice: a large Capesize bulk carrier hold requires full power to fill the space with sufficient ultrasound for an accurate survey, while a small inspection hatch or watertight door void needs a much lower output to avoid overloading the receiver. The same instrument covers both without adjustment beyond a single rotary switch.

The transmitter runs on 12 × MaxE 2100 mAh rechargeable AA batteries, two full sets of which are supplied with the kit alongside a 6-cell charger that accepts 100–240 V AC and delivers a full charge in approximately 3 hours. An external 12–24 V DC power input socket is also fitted for applications where a shore or vessel power supply is available, removing battery dependence entirely for extended surveys. In its padded soft-pouch the transmitter achieves IP40 protection with emitters exposed during normal use, rising to IP42 with the cover secured for storage. It is manufactured to CE, UKCA, and RoHS standards and complies with BS EN 60945:2002 — the maritime standard for navigation and radio communication equipment. Transmitter warranty is 3 years.

Inspection Microphone and Telescopic Extension

Two flexible inspection microphones are supplied with every Hatch Sure kit, each measuring 240 × 12 × 15 mm with a rubber sleeve fitted. The stainless-steel flexible gooseneck design allows the tip to be angled into corners, along compressed rubber seals, and around hatch cover cleats that a rigid probe could not reach. The microphone connects to the telescopic extension via a BNC connector. The telescopic extension extends to 1.215 m (4 ft) and collapses to 0.4 m (16 inches) for storage, weighing 300 g. This reach means a single operator standing on the deck can scan the entire width of a hatch panel seal, including the centreline, without climbing or stretching dangerously. A wrist strap is fitted to the extension for secure handling at height. The inspection microphone carries a 6-month warranty and the telescopic extension a 1-year warranty.

Cygnus Hatch Sure for Ships — Ultrasonic Hatch Cover Weathertightness Tester

Purpose-built for weathertightness testing of cargo hatch covers on dry cargo vessels, the Cygnus Hatch Sure for Ships is used by marine surveyors, cargo superintendents, and ship operators to confirm that cargo holds are sealed to the standard required before and after loading. It is ABS Type Approved and accepted by P&I clubs, making its results recognised and defensible for insurance and Classification Society purposes.

Where water hose testing requires the deck to be cleared, the cargo hold to be empty, and a team of personnel to manage the test, the Cygnus Hatch Sure for Ships needs none of that. A single surveyor boards the vessel, places the transmitter in the hold — suspended above bulk cargo if necessary using the supplied sling and 4-point anchor system — and scans the hatch panels from the deck above. The full survey of a standard bulk carrier hold can be completed in a fraction of the time that a water hose test requires, and because it uses ultrasound rather than water, it causes no pollution and poses no risk to loaded cargo.

The transmitter’s 6 adjustable power levels mean the same instrument is equally effective on large Capesize and Panamax bulk carriers as it is on smaller coasters, general cargo vessels, and even yacht hatches and inspection hatches — a range no fixed-output tester can match. Results are displayed simultaneously as an Open Hatch percentage and a dB sound level reading, giving the surveyor both the clear pass/fail indicator and the underlying measurement in a single glance.

At 3.8 kg the complete kit fits in a rucksack-style carry case light enough to be hand-carried as aircraft cabin baggage — a practical detail that matters when surveyors are flying between ports at short notice. The receiver’s neck and waist straps leave both hands free for climbing between decks, operating the microphone, and marking leaks with chalk as they are found. The technical specifications of this variant are identical to the general-purpose Hatch Sure listed above.

Accessories and Replacement Parts

Every component of the Cygnus Hatch Sure system is available as a genuine Cygnus replacement part, ensuring that a damaged accessory in the field never brings a survey programme to a halt. All accessories meet the same quality standards as the core system and are covered by Cygnus Instruments’ warranty terms. A minimum order value of £100 applies.

Inspection Microphone

The replacement inspection microphone for the Cygnus Hatch Sure measures 235 × 10 mm and connects to the telescopic extension or directly to the receiver via a BNC connector. It is the primary leak-locating tool in the system — the flexible tip is pressed along the seal line while the operator listens through the headphones for the characteristic tone that indicates ultrasound passing through a gap. Keeping a spare microphone available ensures a survey can continue without interruption if the primary unit is damaged. The microphone must not be immersed in liquid as this will prevent detection of ultrasound.

Inspection Microphone Covers

Spare foam protective covers for the tip of the Cygnus Hatch Sure inspection microphone. These covers protect the microphone from physical contamination and mechanical damage during transport and storage in demanding environments, extending the working life of the microphone between replacements.

Telescopic Extension

The replacement telescopic extension extends the operator’s reach to 1.215 m, collapsing to 0.4 m for storage, and weighs 300 g. It connects to the inspection microphone via BNC and is fitted with a wrist strap. On large hatch panels and hatches where the seal runs across the centre of the cover, the telescopic extension is what makes single-operator surveying physically possible — without it, large sections of the seal cannot be reached safely from the deck edge.

Tripod

A dedicated tripod for stable positioning of the Cygnus Hatch Sure transmitter. The tripod is particularly useful when testing watertight doors, structural windows, and vertical sealing surfaces where the transmitter needs to be held at a fixed height and orientation without manual support. It allows the operator to set the transmitter in position, step outside the compartment, and begin scanning without an assistant to hold the unit.

Tripod Bracket with Velcro

The tripod bracket with velcro attachment mounts the Cygnus Hatch Sure transmitter securely to the tripod or to a flat surface. It provides a stable, repeatable transmitter position for door and panel seal testing — important when variable transmitter positioning between surveys would affect the Open Hatch calibration reference.

Neckband Headphones

Replacement neckband-style headphones for the Cygnus Hatch Sure receiver, connecting via a standard 3.5 mm jack plug. The neckband design allows the headphones to be worn comfortably beneath a hard hat or safety helmet — a requirement on most commercial vessels and industrial sites. The audible signal the headphones deliver is an essential part of the leak-finding process: the operator hears the rising tone as the microphone approaches a leak, allowing them to slow down, sweep more tightly, and pinpoint the exact defect location before marking it.

Batteries for Hatch Sure Receiver — PP3 NiMH MaxE

Genuine replacement 9 V PP3 NiMH MaxE rechargeable battery for the Cygnus Hatch Sure receiver. The receiver battery provides 4 to 5 hours of continuous operation per charge. It is worth noting that low battery condition does not degrade the performance or accuracy of the Hatch Sure system — but replacing an ageing battery with a genuine MaxE unit ensures the battery level indicator on the receiver display reads correctly and the low-battery warning triggers at the right threshold.

Batteries — 6 × AA NiMH MaxE

Replacement set of 6 × AA NiMH MaxE rechargeable batteries for the Cygnus Hatch Sure transmitter, each with a 2100 mAh capacity. The transmitter requires 12 AA batteries in total (two sets of 6), and the standard kit includes two full sets from new. When batteries reach the end of their service life, replacing them with genuine Cygnus-recommended MaxE cells maintains the rated 4-hour transmitter operating time and ensures the battery status LED on the transmitter continues to indicate correctly — a green flashing LED confirms good batteries; red indicates insufficient voltage for reliable operation.

Battery Charger KH980

Replacement 6-cell battery charger for the Cygnus Hatch Sure kit, compatible with both the receiver PP3 and transmitter AA MaxE batteries. The charger accepts 100–240 V AC at 50–60 Hz, making it compatible with mains power supplies worldwide — important for surveyors working across multiple countries and port locations. A full charge is delivered in approximately 3 hours.

BNC Straight Adapter

Replacement BNC straight adapter for the Cygnus Hatch Sure receiver. This adapter is used to connect the inspection microphone directly to the receiver when operating without the telescopic extension for example, when testing a low door seal at floor level or working in a confined space where the extension is not required. It is a small component but a critical one: without it, the microphone cannot be connected to the receiver.

Where Cygnus Leak Detection Equipment Is Used

Marine Cargo Operations

The shipping industry uses the Cygnus Hatch Sure as the standard tool for cargo hatch cover weathertightness surveys on bulk carriers, container ships, and general cargo vessels. Marine surveyors use it to conduct pre-loading inspections that confirm hatch covers are sealed before weather-sensitive cargo such as grain, steel coil, fertiliser, or coal is loaded. P&I clubs require documented weathertightness testing as evidence when cargo damage claims involving water ingress are disputed. Hull underwriters use it at the point of charter or sale to establish the condition of hatch seals. Ship operators run periodic checks as part of planned maintenance programmes to catch seal degradation before it results in a damage claim.

The Open Hatch calibration method provides a result that is objective and consistent across different surveyors and survey dates — making it far more defensible in a P&I dispute than a visual inspection record or a passed water hose test conducted under different conditions.

Offshore Oil and Gas

Offshore platforms are subject to continuous environmental loading from wind, wave, and spray, and their closing appliances — access hatches, watertight doors, accommodation module windows, and pressurised compartment covers — must maintain their integrity throughout a platform’s operational life. The Cygnus Hatch Sure’s operating temperature range of −20°C to +50°C, IP65 weatherproof rating, and compliance with CE, UKCA, and RoHS standards make it suited to the regulatory environment and physical conditions of offshore operations. Platform maintenance teams and inspection contractors use it to verify closing appliance integrity as part of routine scheduled inspection programmes.

Transportation and Vehicles

The 6 adjustable power levels on the transmitter allow the Cygnus Hatch Sure to scale down from large enclosed spaces to the much smaller void volumes of vehicle door seals, roof hatch seals, and cargo access panels. Rail vehicles, ferries, heavy plant cabs, and armoured vehicles all have closing appliances that must maintain a weathertight or pressurised seal under operational conditions — and all can be tested using the same equipment and the same methodology as a ship’s hatch cover, simply by selecting a lower transmitter power level appropriate to the space.

Industrial Leak Testing

Any industrial application where a sealed compartment, access door, or closing appliance needs to be verified as airtight or weathertight can be addressed using the Hatch Sure. Electrical enclosure seals, pressure vessel inspection covers, ductwork access hatches, and structural building envelopes are all testable using the same non-destructive ultrasonic method — no pressure, no water, no disruption to plant operation.

Calibration, Servicing and Quality Assurance

The Cygnus Hatch Sure requires calibration every two years to maintain survey-grade accuracy. Calibration is carried out by Cygnus Instruments or by an Authorised Cygnus Service Centre. There are no user-serviceable parts inside the system — all repair work is performed by Cygnus or its authorised network, protecting the integrity of the calibration throughout the instrument’s service life.

Cygnus Instruments is an ISO 9001 accredited manufacturer. The Cygnus Hatch Sure is ABS Type Approved and carries CE, UKCA, and RoHS certification, complying with BS EN 60945:2002 — the international standard for maritime navigation and radio communication equipment. Product training courses are available from Cygnus Instruments and from Authorised Distributors, with a certificate of training issued on completion.