Reliable marine inspections for safety, compliance, and performance.

At Ned Marine we provide comprehensive inspections and surveys for many of our clients. Do you want to assess the condition, safety, and compliance of your vessels, offshore structures, or industrial assets? Our certified surveyors conduct pre-conditional surveys, special surveys, and hull inspections, identifying structural issues, corrosion, or coating failures before they become costly problems.

We work globally, on land, in dock, and at sea, ensuring compliance with classification societies and industry regulations. Whether for preventive maintenance or regulatory requirements, our inspections deliver clear, detailed reports to help you make informed decisions and maintain operational excellence.

This method will provide indications of surface and subsurface discontinuities, will determine by the use of the proper  technique the depth and exact size of the damage in the material. Ultrasonic  pulses are directed into the test object which produces echoes and reflections

which then indicate the presence, absence and location of flaws, interface and/or discontinuities.

Scientific Principles 

High frequency sound waves are sent into a material by use of a transducer. The sound waves travel through the material and are received by the same transducer or a second transducer. The amount of energy transmitted or received and the time the energy is received are analysed to determine the presence of flaws. Changes in material thickness, and changes in material properties can also be measured.

Main Uses

Used to locate surface and subsurface defects in many materials including metals, plastics, and wood. Ultrasonic inspection is also used to measure the thickness of materials and otherwise characterize properties of material based on sound velocity and attenuation measurements.

Main Advantages 

• depth of penetration for flaw detection or measurement is superior to other methods;
• only single sided access is required;
• provides distance information;
• minimum part preparation is required;
• method can be used for much more than just flaw detection.

Disadvantages 

• surface must be accessible to probe and couplant;
• skill and training required is more extensive than other techniques;
• surface finish and roughness can interfere with inspection;
• thin parts may be difficult to inspect;
• linear defects oriented parallel to the sound beam can go undetected;
• reference standards are often needed.

The Magnetic Particle method can be used only on ferromagnetic materials to reveal surface discontinuities and to a limited degree, those located below the surface. The sensitivity of this method decreases rapidly with depths below the surface being examined and therefore, it is used primarily to examine for surface discontinuities. Ned Marine offers large, stationary in-house test units for high volume inspection and a full range of portable units designed for reliable, efficient testing in the field.

Scientific Principles

A magnetic field is applied to a component made from ferromagnetic material. The magnetic lines of force travel through the material, and exit and re-enter the material at the poles. Defects such as crack or voids cannot support as much flux, and force some of the flux outside of the part. Magnetic particles distributed over the component will be attracted by the areas of flow leakage and will give a visible indication. 

Main Uses

Used to inspect ferromagnetic materials (those that can be magnetized) for defects that result in a transition in the magnetic permeability of a material. Magnetic particle inspection can detect surface and near surface defects.

Main Advantages

• large surface areas of complex parts can be inspected rapidly;
• can detect surface and subsurface flaws;
• surface preparation is less critical than it is in penetrating inspection;
• magnetic particle indications are produced directly on the surface of the part and form an image of the discontinuity;
• equipment costs are relatively low.

Disadvantages

• only ferromagnetic materials can be inspected;
• proper alignment of magnetic field and defect is critical;
• large currents are needed for very large parts;
• requires relatively smooth surface;
• paint or other nonmagnetic coverings adversely affect sensitivity;
• demagnetization and post cleaning is usually necessary.

Penetrant Testing

The Liquid Penetrant Method is used to detect discontinuities which are open to the surface of the material being examined. This method may be used on both ferrous and nonferrous materials. Liquid Penetrant examination may be used for the detection of surface discontinuities such as cracks, seams, laps, cold shuts, laminations and porosity. We can provide both visible and fluorescent Liquid Penetrant Examination Services.

Scientific Principles

Penetrant solution is applied to the surface of a clean component. The liquid is pulled into surface-breaking defects by capillary action. Excess penetrant material is carefully cleaned from the surface. A developer is applied to pull the trapped penetrant back to the surface where it is spread out and forms an indication. The indication is much easier to see than the actual defect.

Main Uses

Used to locate cracks, porosity, and other defects that break the surface of a material and have enough volume to trap and hold the penetrant material. Liquid penetrant testing is used to inspect large areas very efficiently and will work on most non-porous materials.

Main advantages

• large surface areas or large volumes of parts/materials can be inspected rapidly and at low cost;
• parts with complex geometry are routinely inspected;
• indications are produced directly on surface of the part providing a visual image of the discontinuity;
• equipment investment is minimal.

Disadvantages

• detects only surface flaws;
• surface preparation is critical as contaminants can mask defects, surface breaking defects;
• requires a relatively smooth and nonporous surface;
• post cleaning is necessary to remove chemicals;
• requires multiple operations under controlled conditions;
• chemical handling precautions are necessary (toxicity, fire, waste).

Visual Examination is generally used to determine such things as the surface condition of the part, reinforcement and undercutting of welds, alignment of mating surfaces, shape or evidence of leaking.

Methods employed may be either:

• direct visual examination;
• remote visual examination;
• translucent visual examination using artificial directional lighting.

Ned Marine provides certified Visual Inspectors to various codes.

Vacuum box bubble test is one of the safest and reliable non-destructive testing methods. Vacuum Box Testing is used in order to locate seam leaks in the welds of storage tanks. A detergent solution is commonly used in this testing method and a vacuum pump is attached to the storage tank. If a leak or fault is detected, there will appear a bubble over the leak.

Vacuum Box Testing can be used on lap welds, shell to annular welds, butt welds, pressure vessels, piping systems, among many others. Vacuum Box Testing is great as it is capable of immediately locating any leaks. It can also detect the smallest leaks inside a given area.

Ned Marine Services B.V. professionals are trained and experienced in vacuum box bubble test method in accordance with ASME BPVC code section V, article 10, Appendix II.

Please contact us here if you require any more information or a quote.

Eddy Current Testing detects surface and near-surface flaws in conductive materials using electromagnetic fields. Ideal for flaw detection, material sorting, and coating thickness measurement.

The Eddy Current method is used to detect discontinuities in pipe and tubing by subjecting the material to a strong external magnetic field. A test coil which includes Eddy Currents in the material is used for this purpose. If a discontinuity exists, there will be variations in the Eddy Currents produced and these will be indicated by a signal in the test equipment.

Scientific Principles

Alternating electrical current is passed through a coil producing a magnetic field. When the coil is placed near a conductive material, the changing magnetic field induces current flow in the material. These currents travel in closed loops and are called eddy currents. Eddy currents produce their own magnetic field that can be measured and used to find flaws and characterize conductivity, permeability, and dimensional features.

Main Uses

Used to detect surface and near-surface flaws in conductive materials, such as the metals. Eddy current inspection is also used to sort materials based on electrical conductivity and magnetic permeability, and measures the thickness of thin sheets of metal and non-conductive coatings such as paint.

Main Advantages

• detects surface and near surface defects;
• test probe does not need to contact the part;
• method can be used for more than flaw detection;
• minimum part preparation is required.

Disadvantages

• only conductive materials can be inspected;
• ferromagnetic materials require special treatment to address magnetic permeability;
• depth of penetration is limited;
• flaws that lie parallel to the inspection probe coil winding direction can go undetected;
• skill and training required is more extensive than other techniques;
• surface finish and roughness may interfere;
• reference standards are needed for setup.

Please contact us here if you require any more information or a quote.