Cygnus Instruments Ltd

Paul Fahy

Introduction to ultrasonic hatch cover testing

www.cygnus-instruments.com

Introduction

Welcome to Cygnus Instruments

The pioneers in developing multiple echo technology for

material thickness measurement through coatings. For over

25 years.

Cygnus ultrasonic thickness gauges which are employed in

almost every industrial application around the world.

With successful diversification, Cygnus now carries three

ultrasonic product lines - thickness gauges, hatch cover leak

detectors and industrial leak detectors.

Product Overview

ROV mountable

thickness gauges

2000 m and 4000 m

depth rated

designed for safely

measuring metal

thickness in

potentially explosive

environments

Cygnus 2 Hands Free

Designed for use in rope

access surveys

Product Overview

Cygnus Dive is the latest innovation

from Cygnus Instruments and is a

wrist-mounted underwater

thickness gauge...

Cygnus Hatch Sure provides a

quick and effective method of

evaluating hatch cover seals

Hatch Sure Cygnus Hatch Sure is a Classification Society Type Approved, ultrasonic system for rapid and thorough testing of the weather tightness of cargo hatch covers.

A single operator can use the device.

It does not interfere with any other vessel operations when in use.

Supplied with traceable calibration certificate & 3 year warranty

Ultrasonic testing has proved to be the most reliable method of

assessing the condition of seals on a hatch cover.

Clean

Fast

Non polluting

Detection of defective seals prevents damage to cargo and

saves time for all interested parties.

Potential savings can be hundreds of thousands US$ per vessel

Leaking hatches are the largest single cause of insurance claims

Saves money

Why does anyone need to

buy a hatch tester

Presentation Outline Principles of the Technique:

Principles of sound

Overview of ultrasonic hatch cover testing

The Product:

The kit and the parts

The operation of the equipment

Operation of the System:

Setting Open Hatch calibration value

Testing for leaks

Why and How is Ultrasonic testing relevant?:

Owners obligations

Case Reference: Cargo Claim

What is Ultrasound?

Ultrasound is a sound wave beyond the range of human hearing

The normal range of human hearing is between about

20Hz and 20kHz, but the range becomes less as we get

older. Sounds with frequencies above about 20kHz are

called ultrasound.

What does it look like?

Ultrasound energy travels in straight lines from the 19 transmitter elements, each forming a cone-shaped beam as it moves away from the transmitter

Transmitter Beam Spread Pattern (side view)

Ultrasound in a cargo hold

Ultrasound travels through air and is reflected from all hard surfaces so that in the enclosed hold, reflections of ultrasound bouncing off the sides evenly distribute the amount of measurable ultrasound

Hatch-Coming & Hatch Cover

Do

Fig 7.1 Transmitter Centrally Positioned.

Hatch coaming & covers

Ultrasonic Testing

If a cargo hold is not perfectly sealed, some ultrasound will leak through the gaps to the outside

An ultrasonic receiver is used to find those leaks from the outside

Why Ultrasonics?

This method of testing hatch covers has the following advantages:

Reliable, accurate, rapid and repeatable

No pollution

OK to carry out after cargo loaded - vessel in sea-going condition

OK in different light conditions and sub-zero temperatures

Also test cargo access areas (bow, side & stern doors) or any opening that needs to be sealed

Cygnus Hatch Sure Kit (2.5Kg)

System Overview

Battery-powered transmitter with 19 x 40 kHz ultrasound emitters, produces an

omni-directional sound field, which is distributed throughout the cargo hold

The receiver part of the system displays the sound energy level that passes

through gaps in the enclosed cargo hold, to enable the location of leaks to be

quickly and accurately identified

Telescopic Extension

Hatch Sure

Transmitter

Neckband

Headphones

Remote

Microphone

Hatch Sure

Receiver

Worn by Surveyor – Outside Cargo Hold Inside Cargo Hold

Remote

Control to

Transmitter

The Transmitter

Supplied in a pouch for protection

When in use, secure open the pouch lid to expose the array of emitters

Shoulder strap (not shown) fits to pouch for carrying or to suspend transmitter against a flat, vertical surface if required to test a door or window

Sling with 4 anchor points is supplied for suspending the transmitter unit in the cargo hold (if hold contains cargo such as grain or if no convenient surface)

Transmitter Controls

Power On/Off switch turns the transmitter power on and off!

Remote ON: enables remote control of transmitter from the receiver

Remote OFF: transmitter operates continuously when the power is on

LED flashes when in operation:

flashing GREEN LED = batteries are good

flashing RED LED = battery voltage is insufficient for reliable operation

The Receiver

Neck and waist

straps - for

convenient, safe,

hands-free

operation

Supplied in

weatherproof

case

Receiver Display

Receiver Keypad

OH dB

HOLD MAX

Power

Backlight SET OH

Volume increase

Remote Volume

decrease

What is “Open Hatch”?

Open Hatch Value = the ultrasound signal level measured by the receiver when

the hatch cover is fully or partially open (or through an access hatch)

This measured signal level (in dB) is then set to indicate 100 % Open Hatch (OH)

When looking for leaks, the percentage scale is simple to understand and

provides a means of assessment for the severity of a detected leak, since:

ANY LEAK > 10 % OPEN HATCH (OH) = THE SEAL IS NOT WEATHERTIGHT

Tanktop

Open Hatch Gap

Hatch Covers

Deck

To set the Open Hatch Value

one hatch cover is partially

opened so the inspection

microphone can be inserted

into the gap directly above the

transmitter

Listening for Leaks

1. After the Open Hatch value has been set

2. Close hatch covers and access hatches

3. Wear the headphones and scan along the joints and seals with the microphone

4. Once the ultrasound has been heard the surveyor can stop, home-in on the area

and pinpoint the leaky section, then chalk mark it clearly as a leak

Product Training

PRODUCT TRAINING: Cygnus Instruments Ltd and its Authorised Distributors provide certified product training on the operation of the Cygnus Hatch Sure equipment.

Offers consistency of equipment use throughout an organisation and provides reference documentation for auditing and additional in-house training

Chart highlighting some of the common causes of damage, loss and personal injury associated with

cargo holds and hatch covers

"Cause of Large Cargo Claims by Value"

Dry Bulk and General Cargo Vessels

5%20%

33%18%

11%

8% 5%

Pipe Failure in Hold Cargo or documents faulty

Hatch Cover Leaks Ships staff fault

Engine room problem Cargo Stowage problem

Strucural fault

Cargo - Di-Ammonium Phosphate (fertilizer), totalling about 27,000 mt.

Voyage - Morocco to China.

Damage - Claim

Case 1:

Case 2:

Cargo - Steel products.

Voyage - China to Flushing, Holland.

Damage - Ultrasonic test of hatches revealed leakages at the corners

of cross joints of the hatch covers.

Claim -

The widespread acceptance of the advantage for each vessel to have it’s own

ultrasonic hatch cover tester is proven to reduce hatch maintenance costs and the

number of claims.

Some of our Customers

Ship Owners/Managers

Cygnus Instruments Ltd

Paul Fahy

Cygnus Hatch Sure Sales

www.cygnus-instruments.com

Thank you