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What Is The Importance Of Hull Inspection

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  • 26-07-2022
What Is The Importance Of Hull Inspection

What is the importance of hull inspection? We look at why hull inspections are important and the methods of hull inspection.

Hull Inspections

In the past, inspectors and cleaners had to be strong swimmers to view the barnacles and seaweed that found itself attached to the hull of a ship. 

Now that ships and technology have become more sophisticated, we can undergo safer and more underwater ship hull inspections. Ship hull inspections have become even more imperative because the stakes are also higher.

With more and bigger ships carrying more cargo and people across long distances, the safety and operation of ships must be upheld at all times. Regular hull inspections are of the utmost importance to ensure the safety of a ship. 

It only takes one or two structural problems that occur out of sight to create a significant risk to the safety and operation of a ship and its cargo.

Whether it is a crack, dent, irregularity, or leak, it could end up compromising your ship's hull over time.

Emergency inspections also exist to confirm that a vessel has not suffered any damage that could compromise the safety of the people on board. An emergency inspection may take place if the ship has hit the seafloor or an object that was floating in the water. 

Modern services involve deploying remotely operated vehicles (ROVs) to do a sweeping review of the underwater hull.

Boat Structural Inspections

ROVs are highly beneficial for shop hull surveys. They are quickly and easily deployable, require no certifications to operate, no crew members are put in danger when inspecting underwater, and they can record videos to SD cards for proper evaluation post-inspection. Hull inspections done regularly can help to monitor your vessel's paintwork.

While the paint used on ships is designed to offer strong resistance against biofouling organisms, currents, ocean environments and water temperatures, it comes at a steep price. 

Regularly checking the condition of your ship's paint will help you keep track of how protected your ship is from weather and temperature. A concern of underwater hull cleaning is non-native and alien invasive species (AIS) that can become attached to a hull throughout a ship's journey.

The problem arises when these species are released into habitats that are not right for them. 

The invasive species could end up repopulating and competing with local, natural species, eventually leading to the local species dying out as a result of a lack of enough food for both species, attacks from the invasive species, or not enough room for both species.

In conclusion, hull inspections can affect the habitat of local species by carrying alien invasive species and releasing them into the wrong habitat. The vessel of the hull that is carrying these species can come across operational issues as it slows the ship and means that more fuel is needed to create more speed to counteract the opposing force.

An ROV can perform a preliminary assessment by determining whether hull cleaning is the appropriate action to take for environmental and operational reasons.

Why Are Hull Inspections Important?

 Ensure Structural Integrity

The structural integrity of a ship's hull is vital for ensuring the crew's safety. A hull's integrity is also essential for logistic efficiency. All sailing vessels operate safely by identifying and addressing corrosions, cracks, dents, discolouration, and irregularities.

In the 2021 Safety and Shipping Review, 40% of the 49 ships that were lost and just over 2,700 incidents in that year were caused by physical damage.

A portion of these extremely dangerous and costly situations could have been avoided had the ships been through thorough inspections and maintenance work.

 Improve Port Security

Contraband transportation is occurring more frequently by water than by air because transportation via waterways is lower in cost and is protected with lighter security. 

From 2017 to 2019, seizures of cocaine from private and commercial vessels have gone from 22.4 to 73.2 metric tons, according to Resilience360, a cloud-based risk management solution that assesses risks across the supply chain of the German logistics company Deutsche Post DHL.

In many criminal cases, ship crew are caught completely unaware of illegal goods on board. That's why conducting dedicated and deliberate security checks during hull inspections is essential for preventing dangerous substances from entering a country.

 Optimise Maintenance Scheduling

Hull inspections are important to optimise maintenance schedules. Knowing the quality status of your large assets will make consistent and accurate maintenance schedules.

This way, you avoid overspending, unnecessary repairs, and neglecting components that have deteriorated and could cause incidents.

 Monitor Paint Status

Maintaining paint integrity reduces overall maintenance costs because you prevent costly damage from occurring on a ship's hull if the paint has worn away. Apply antifouling paint to improve water flow and operational efficiency and to protect your ship from corrosion and organic growth.

When inspectors identify certain points of exterior paint that show degradation, they may advise a reapplication of antifouling paint. The reapplication prevents further entry of AIS and prevents corrosive damage to the hull of the ship while the paint stays on.

What Is The Importance Of Hull Inspection?

 Discover Invasive Species

Due to invasive species, around 42% of endangered or threatened species are at risk. Many AIS can go undetected, such as Killer Algae and Zebra Mussels, by clinging onto the side of ship hulls.

These species can be unintentionally distributed to different ecosystems, seas, and countries. Once they establish themselves, they can reproduce and spread quickly, causing irreparable harm to the surrounding environment.

Biodiversity and aquaculture production is burdened by the sudden alien species and require identification and removal before these concerns multiply.

By removing these species from ship hulls during inspections, we can minimise the environmental impact that invasive species have in foreign ecosystems.

What is a Hull Inspection?

The hull of a ship is the watertight exterior, opened or enclosed by a deck. The hull is your first line of defence against cracks, leaks, and dents.

As we have previously said, regular hull inspections are vital to maintaining the safety and smooth operation of your ship. There are two general types of hull inspections due to the various components, defects, and situations of different types of ships.


GVI Inspections

GVI stands for General Visual Inspections. General visual inspections are a self-explaining type of inspection that shows the overall conditions and status of a ship in a report. 

These inspections look at biofouling, cracks, discolouration, and any physical defects in a ship.

They are conducted from a moderate distance, about an arm's length away from the given component, to give a general overview of the hull's status. 

GVI inspections can sometimes use a mirror to enhance visual access to exposed or areas that are hard to get to. They can either use daylight, flashlights, or an ROV's light to increase visibility where the inspection is taking place.


CVI Inspections

CVI stands for Close Visual Inspections. Close visual inspections are crucial to identifying areas in more depth than GVI inspections. An extensive, detailed, and close-up examination can detect potential and visible damages, failures, and irregularities.

Close visual inspections look at various components and structures, such as anchors, hulls, propellers, and sea chests. Sometimes, surface cleaning has to be done before the inspection to gain clear and absolute access to components and areas. 

Tools are often required to acquire further access, such as probes, measuring tools, and gauges.

CVIs also utilize additional equipment to enhance the inspection's quality. Natural light can be supplemented by flashlights and auxiliary lights. Turbid waters require imaging sonar tools to penetrate the murky water and see what is otherwise hidden

Methods of Hull Inspection

Dry Docking

External inspections can be difficult when the majority of a ship is submerged. Dry-docking is a traditional method of allowing comprehensive hull inspections to take place on a dry-dock block. It is a particularly time-consuming and expensive method to perform because the entire ship needs to be removed from a waterway and carefully placed onto dry-dock blocks.

Large ships make this a very dangerous and complex procedure because heavy equipment, a qualified dockmaster, and crew are needed to prevent the ship from capsizing and risking the health and safety of the crew and involved persons

Many boat owners and dockmasters consider underwater inspections as the default method of hull inspections because of how much dry-docking costs, takes in terms of time, and the potential to lead to various complications and risks.

Methods Of Hull Inspection


'Underwater Inspection in Lieu of Dry-Docking' (UWILD) is, by far, a safer and more efficient alternative to marine vessel inspections. UWILD take place, you guessed it, underwater, where the submerged hull of the ship resides.

Underwater inspections reduce the frequency of inspections needed, saving you money and time.

However, dry-docking is occasionally necessary. Dry-docking may be the only option suitable to repair propellers, rudders, sea valves, shell plating, stern frames, sea chests, and thrusters.

The vessel's owner(s) needs to be qualified to conduct a UWILD. Once they are, qualified and approved divers will perform a UWILD by navigating under the hull of a ship to visually inspect the necessary components there.

New equipment and technology mean that ROVs are a popular replacement for dive teams, making UWILD inspections that much safer.

If you are looking for yacht or marine hull surveys in Surrey and the surrounding areas contact our professional boat surveyor today. 

We work throughout Surrey and the surrounding areas including Kent, Sussex, Hampshire, Berkshire and Greater London. 

We can also travel throughout the UK if required.

Marine Hull Surveyors Hampshire