VESSEL REVIEW | MJM Enterprise – Survey boat to support offshore renewable energy sector

Marshall Jakeman Marine (MJM), a UK- company specialising in vessel construction and the provision of marine services, recently welcomed a new survey vessel to its fleet.

Built by MJM to a design by naval architecture firm S.C. McAllister and Company, MJM Enterprise is designed to fulfil the future requirements of marine renewable energy projects, offering rapid mobilisation for survey and related activities, onboard processing and spacious, comfortable accommodation.

A compact multi-role vessel

MJM Enterprise will cater to multi-disciplined projects, including hydrographic and geophysical surveys, remotely operated vehicle (ROV) inspection, and benthic/environmental sampling. Provision for a four-point mooring system will provide a solution for diving works if required.

"We coordinated with Ian Paton and his team at S.C. McAllister and Company and specified exactly what we wanted, based on a previous design with some changes," Chris Jakeman, Managing Director at MJM, told Baird Maritime. "We had a lot of input into the design and then had to finish off the works with it."

Jakeman said the company's earlier dive support vessel, the 2015-built Curtiss Marshall, served as a starting point. The requirement was for a service craft to be built following the same criteria, with the only exception being that the new vessel need not have any dive equipment onboard, unlike its predecessor.

"It was built to fill a gap in the market," added Jakeman. "There are not that many 24-metre (79-foot) vessels that could have bridged the gap between 15-metre boats and larger 40-metre (130-foot) vessels for survey work."

"This is a development of what we did for Curtiss Marshall, which we also designed," Ian Paton, Naval Architect at S.C. McAllister and Company, explained. "MJM wanted to be able to work in more severe sea conditions, which could otherwise limit their ability to conduct survey work."

Paton added that MJM had specific requirements related to fuel, fresh water, and the number of baths. The vessel has a wider beam, allowing the installation of a crane on the side.

"Rather than start with a blank sheet of paper, we took something we worked on before and tried to develop the design even further," said Paton. "It's a high-specification boat for survey work in response to demand for subsea vessels. The entire vessel is of a fairly conventional design that has also been optimised to minimise fuel consumption and maximise thrust from the available power."

Deck equipment and electronics suite optimised for survey work

MJM Enterprise has an LOA of 26.7 metres (87.6 feet), a beam of 8.1 metres (27 feet), and a draught of three metres (9.8 feet). The propulsion arrangement includes two Doosan 4V158TIH main engines driving fixed-pitch propellers to deliver a speed of 10 knots.

Also fitted are a Kort Propulsion KT170 bow thruster, a Hydromaster retractable stern azimuthing thruster, two 79kVA generators, and a 125kW generator. The latter can allow the vessel to sail at up to five knots without having to rely on the main engines. The vessel is also fitted with an anti-cavitation tunnel sitting in the gap between the rudder and the propellers.

"We've removed the electrical motor and replaced it with a coupling," said Jakeman. "We've also approached a company to supply a hydraulic motor and integrate it into the system. We didn't want to have to put two big generators on board just to drive the other machinery, or these would have taken up a lot of space in the engine room."

The vessel's key features include an 85-square-metre (910-square-foot) working deck capable of accommodating two 20-foot containers. The vessel also provides various sensor mounting options, including a 1.2-metre (3.9-foot) moonpool for through-hull sensor deployment.

To improve seakeeping capabilities, MJM Enterprise incorporates a dynamic positioning system and a passive, anti-roll tank. The latter significantly reduces the vessel's roll motion, thereby extending available weather windows, as well as fulfils the owner's need for stability at low speeds.

"We wanted improved all-weather capability compared to what we had with Curtiss Marshall," said Jakeman.

A five-tonne A-frame with integrated winch offers five metres (16 feet) of internal clearance and flanges on both the outboard and inboard sides, expanding the towing width. With additional booms up top, and coupled with a crane rated to carry 38-tonnes, the A-frame is ideal for survey, ROV support, shallow geotechnical data collection, and environmental operations.

MJM incorporated improvements in the vessel's deck crane to give it greater reach, thus ensuring greater operational flexibility. This and other custom works on the vessel were implemented after the company identified machinery improvements that can be completed in-house instead of outsourced, thus minimising costs and ensuring each piece of equipment is precisely what is needed.

The boat also features mooring and anchor winches and port and starboard removable gunwales for side deployment of assets.

For the electrical installation, MJM approached a local company that reviewed the panel designs and integrated all of these into one main control panel to handle all the electrical distribution. The electronics suite includes Furuno radars, a Simrad autopilot, and ICOM VHF and MF/HF radios.

"We opted for three distribution bars instead of just one," added Jakeman. "We also had them integrate the bilge monitoring system and create a separate panel that tied into the main panel. It's all designed as a single solution rather than multiple separate panels."

Highly stable platform with adequate facilities

The vessel has 20 berths, including 12 for charterer personnel. A spacious working galley can serve up to 10 people at a time, while a separate lounge area provides a comfortable space for relaxation. Other facilities include a client office and a dedicated laboratory/processing room.

"We encountered challenges in getting a solution for the anti-roll system and in placing additional compartments in the existing design," Jakeman told Baird Maritime. "We also started the design work in a hurry as we wanted to get everything rolling before the imposition of the Tier II emissions cut-off, which was then set for the second half of December 2020."

Jakeman also remarked that work on the vessel highlighted the importance of spending more time in the earliest stages of development: "From our perspective, we wanted good stability, which means we didn't want the boat to have a large GM (metacentric height) or to be too quick on the roll," he noted. "At the same time, we have a large crane on the port side, which requires a large GM. So, it was a challenge to design something that would be comfortable and not roll too much."

Paton explained that the issue was resolved through the incorporation of ballast tanks and a downflooding tank. The tanks have been raised and can be emptied when the crane is being used for lifting heavy loads.

"As regards regulations, something that was satisfactory and approved quite readily for Curtiss Marshall became more difficult in the case of this vessel," added Paton. "The authorities have also become more stringent when it comes to structural requirements, and we did our best to satisfy these. We learned to be better prepared, as it takes a lot more time to satisfy the authorities and to provide the information and calculations they require."

Paton said the boat also needed to comply with damage stability requirements due to its range. The steel work also needed to be adjusted to accommodate the retractable azimuthing thruster. MJM Enterprise will be available for commercial charter following completion of sea trials.