YARDS BUSY WITH SURVEYS, REPAIRS AND RETROFITS




A range of repair and retrofits projects have been completed amid the challenging conditions created by the COVID-19 pandemic

A&P Group in the UK reported a strong first half of the year across all three of its facilities despite the challenges of working during the pandemic, and David McGinley, Chief Executive Officer of Cammell Laird Ship Repairers and Shipbuilders and Atlantic & Peninsula Marine Services in the UK, says the forecast for the rest of 2020 is encouraging for the ship repair, conversion and marine services company, as deferred classification surveys look set to make the last quarter busy for all three facilities. “The knock-on effects of Covid-19 have been vast, and we are anticipating a bottleneck of demand for our drydocks, as shipowners and operators rush to book their classification surveys before the year is out.”

One of A&P Tees’ most significant projects this year involved extending the life of trailing suction hopper dredger Heortnesse by more than 15 years. Carried out over two dockings, the propulsion drives were changed to allow the vessel to operate on two generators instead of three, and the dredge system was refurbished with a new dredge pump, pipework, densitometer and monitoring system. In total, 30 tonnes of steel, the deck-dredge hydraulics, control systems and the alarm and communications systems were all renewed.

The offshore supply vessel Ocean Intervention II underwent refurbishment at A&P Falmouth. The program involved routine repairs and maintenance as part of the ship’s class certification and the fabrication of a custom-designed gondola and modifications to the vessel’s back deck. The 14 tonne gondola was fabricated in advance, and the shape, size and weight of the gondola meant that A&P’s in-house engineers had to fabricate stilts so that a cutter could get beneath the structure and machine the fittings before it was transferred to the dry dock and attached to the hull. Other work included modifying and installing a new main propulsion thruster bed plate and fitting insulation to help minimise the sound from the ship’s thrusters, which was interfering with sonar readings from the sea bed.

Mitsubishi Shipbuilding, a member of Mitsubishi Heavy Industries Group, has retrofitted the first two of its DIA-SOx R series scrubbers on two ultra-large container ships, with approvals gained from both Lloyd’s Register and ClassNK. The scrubber series features a rectangular tower design suitable for ultra-large container ships, and its multi-stream configuration can simultaneously treat exhaust gas discharged from multiple engines in one tower, including the large main engine with output over 75,000kW.

Mitsubishi Shipbuilding has increased production capacity and begun shipments of the DIA-SOx R and also the DIA-SOx C Series tower, suited for LPG carriers and large oil tankers. The cylindrical C Series has been jointly developed with Mitsubishi Kakoki Kaisha and the rectangular R Series with Mitsubishi Hitachi Power Systems.

Goltens Green Technologies’ division in Singapore recently undertook a turnkey project for the simultaneous installation of a Kwang Sung scrubber and a ballast water treatment system on an LNG tanker at Chengxi Shipyard in China. The primary constraint of the scrubber part of the project was the limited size of the existing funnel, and the physical size and configuration of the U-Type venturi scrubber chosen. A major extension to the funnel was identified by all parties as the only viable option. The innovative design delivered managed to retain a somewhat streamlined and aesthetically pleasing “backpack” arrangement. Given the compact engine room and lack of free space on the engine floor level, locating the scrubber seawater supply pumps, associated equipment and ECU units for the BWTS was also a challenge.

Sandeep Seth, President Goltens Worldwide, notes that scrubber projects involve a lot of naval architectural and structural studies including lightship calculations, and sea chest capacity, overboard requirements, sizing of the seawater pump capacity as well as piping design have to be conducted in parallel. It is also important to verify the back pressure generated from the scrubber with engine manufacturers. Power consumption needs to be calculated and load analysis updated to confirm that sufficient power will be available during operation. For the new casing, it was necessary to analyse structural and equipment stress horizontally and vertically and to analyse pipe stress.

There is often reluctance and apathy amongst owners and operators when considering automation at the retrofit stage, says Børge Nogva – President, Høglund Marine Solutions. “We see a trend now where the suppliers of existing systems found onboard typically offer owners a ‘partial’ upgrade, based on this reluctance to approach a full retrofit. This often starts with an upgrade of the ‘top-system’ such as operator-stations and user interfaces. At next yard-stay they continue with major hardware components such as computer processing units and input/output cabinets. While it may seem more cost effective to split the work up in this way, owners may be sleepwalking into a situation where they are effectively paying twice for automation refits, as they are locked into contracts with their supplier, often without upgrade options.”

Nogva say frequently yards will work with their preferred suppliers and manufacturers. Consequently, it is not uncommon to find a bridge or engine control room (ECR) with 10-20 different monitors or stand-alone systems. Operating these multiple, non-integrated systems is a significant challenge for the crew. Maintaining the ECR is problematic in these circumstances too.

A new, complete integrated automation system (IAS) offers a way to untangle the complexity, he says, and retrofits can be completed in around a week. This brings new capabilities for improved vessel efficiency, from cavitation insights with torque and thrust sensors in propulsion units to fuel flow. “At Høglund, we have seen owners generate as much as 20 percent fuel savings just from being able to understand their fuel flow and adjust their propulsion unit accordingly.”

A consolidated IAS also brings in new capabilities for owners to extract and exploit big data and to facilitate remote connectivity. “This allows for low-cost maintenance, repair and update of systems onboard from onshore locations, reducing the need for costly technician call-outs,” says Nogva.

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