Claudia Ohlmeier · 24 January 2020
In the push to modernise class services, DNV GL recently introduced two innovations that make ship surveys more efficient, flexible and safe: online-based remote surveys and thickness measurements carried out by drones.
Sending a surveyor to a vessel costs time and waiting time impacts the vessel’s operational availability. With travel time eliminated and waiting times reduced, remote surveys can be conducted faster than traditional surveys, and the results can be shared immediately through DNV GL’s electronic certificate and documentation system.
Since the spring of 2019 DNV GL classed vessels have been able to take advantage of remote surveys for some inspections. Through an online connection or video-streaming link, a dedicated team of remote surveyors provides support to vessels anywhere in the world.
Traditionally, the regulatory bodies have assumed that experts are always physically present on board to verify the situation. This has been standard procedure both according to regulations and in people’s minds. But times have changed. In the past, with limited communication options, far fewer regulations in place and only basic technology on board, shipowners and classification societies were able to handle surveys in a single visit. Nowadays, with complex technologies on board and dependence on various third-party service suppliers, a single visit is no longer sufficient. Therefore, the industry is demanding the use of advanced communication technologies to support and speed up the process ‒ in a world in which every minute counts.
Remote surveys utilising state-of-the-art technology allow DNV GL to formalise this kind of work, centralise the operation at fewer central units, and enhance transparency by standardising the documentation requirements.
Another advantage of remote surveying is that it provides access to a broader range of competencies, regardless of the ship’s location. “Remote surveys allow us to apply expertise as needed from anywhere the experts are located,” Claudia Ohlmeier, DNV GL Group Leader Port State Control, points out. Since the same remote-survey teams review all types of cases, the results are more consistent while the level of assurance matches that of on-board surveys.
But notwithstanding the growing enthusiasm among customers, not everything can be done remotely, Ohlmeier explains. “Some things are just too critical to determine without an expert being there to physically verify the situation,” she says. “Whether we can conduct a survey remotely is subject to a case-by-case assessment. Our on-board experience is critical in helping us in the office determine whether a remote inspection will be sufficient. In addition, some statutory items may require authorisation by the flag administration by means of a remote inspection.” Around 85 per cent of requests for remote surveys are accepted, with the remaining 15 per cent passed on to the on-site survey process.
DNV GL has the backing of all major flag states. “Remote surveys have been authorised for certain statutory surveys, but so far we have only scratched the surface,” states Dave Wamsley, DNV GL’s principal contact at the Republic of the Marshall Islands (RMI) Maritime and Corporate Registries. “But remote and digital services are progressing at a quick pace, and this is also being driven by communication capabilities,” Wamsley adds.
Drones herald in new era of inspections
Another example of how DNV GL is modernising its class services is visual inspections and steel thickness measurements as part of renewal surveys. Preparing ships for these activities is time-consuming and not without safety issues.
A traditional survey requires rafting, roping or staging so the inspection personnel can reach all relevant structural elements. Rafting takes additional time since the vessel must be ballasted and deballasted; both roping and rafting often require voyage surveying. Setting up staging can even take days. In addition, staging often damages surfaces and coatings that must then be repaired. In certain situations, owners have to hire subcontractors rope access techniques, which is an especially hazardous type of work. These conventional inspection methods expose staff to potentially dangerous situations and make ships unavailable for hire for weeks, which means lost income. Logically, owners have an interest in reducing possible injuries and keeping these times as short as possible.
This led to the idea of using drones instead of letting people work at height. The first step was to attach a high-resolution camera to a drone so surveyors could take a close look at hard-to-reach places and several off-the-shelf drone models were tested.
The result of many months of development work and trials, a medium-sized commercial drone fitted with a special accessory frame was designed and manufactured in-house by the Gdansk DNV GL surveyor team and is now standard equipment for inspections around the world. “Today, we have more than three years of experience performing camera-assisted visual inspections on ships and offshore structures using drones,” Ohlmeier explains. “But our customers expect more. They would like us to cover the full scope of inspections using this advanced technology, including thickness measurements. So, in mid 2018 we decided to venture into this field and began developing a flying thickness measurement system. We built several prototypes and finally arrived at a design that satisfied our requirements.”
After elaborate testing of thickness measurements by drones on different ship types such as MPVs, bulk carriers and shuttle tankers, DNV GL now has the capability to offer owners drone-assisted services including close-up inspection and verification of thickness measurements. However, it is important to note that classification rules and regulations require a wide range of thickness measurements, most of which are typically performed by subcontractors. “Our measurements are only supplemental to what the contractors are doing,” Ohlmeier points out. “We only access structures that cannot be reached by conventional means. We use drones to perform close-up surveys and to verify and confirm that a ship is structurally in good condition as required under class rules. The drone accelerates this spot-checking process dramatically, so we can accomplish it within a single visit. We can even perform it during a voyage or port stay.”