AHSV Merlin conjures cost effective magic for offshore wind

by | 3rd July 2023 | Ship & Boat International, Technology

Home News AHSV Merlin conjures cost effective magic for offshore wind
Merlin, when operated uncrewed, “could increase survey productivity tenfold”, SAFE Boats says

Merlin, when operated uncrewed, “could increase survey productivity tenfold”, SAFE Boats says

Autonomous technology meets alt-fuel readiness in SAFE Boats International’s ambitious AHSV Merlin, which has been carefully developed to conjure up cost efficiency on offshore wind farm pre-assessment missions

As with offshore wind farm support vessels, it’s not unreasonable to expect research and survey vessels to ‘green up’ their operations. After all, there’s a certain irony in using diesel to power vessels tasked with capturing critical data to safeguard oceanic and coastal ecosystems.

Interestingly, Washingtonian boatbuilder SAFE Boats International looks set to give this sector a shake-up with its forward-thinking 23m Autonomous Hydrographic Survey Vessel (AHSV) concept: a semi-displacement monohull developed to accommodate hydrogen technology, thereby potentially enabling zero-emission transits. What’s more, the first AHSV in this new series, to be named Merlin, will incorporate a high degree of autonomous tech wizardry into its operations, freeing up its crew and scientist passengers to concentrate on the data-gathering tasks at hand.

Merlin has been developed by SAFE Boats in collaboration with three key partners. World Marine Design – a venture established by UK-based Walker Marine Design (WMD) – provided the AHSV’s architecture, drawing on its previous experience of designing Jones Act-compliant craft for US boatbuilders. Joining these partners is Mythos AI – which is overseeing implementation of Merlin’s autonomous capabilities, developed specifically for offshore wind farm site pre-assessments – and Echo 81, a distributor of hydrographic survey equipment and marine instrumentation.

‘One-stop shop’

The vessel will be constructed in marine-grade aluminium at SAFE Boats’ facility in Tacoma, Washington, and will initially be used to support the US’ burgeoning offshore wind sector. “Our market research predicts a surge in demand for survey vessels and hydrographers, both of which are in limited supply in the US,” SAFE Boats tells Ship & Boat International.

As such, Mythos AI’s autonomous tech should expand these vessels’ range and capability to fulfil current levels of US demand for offshore survey work. “However, we believe Merlin could provide inland waterway surveys as well, such as on the Mississippi River and in large ports,” SAFE Boats adds. “The size of Merlin ensures capable sea-handling while also being compact enough to berth in small, shallow harbours” (see Technical Particulars).

Merlin will effectively be delivered to survey companies ‘ready to roll’, thanks to the boat’s complete geophysical survey and autonomous navigation suite, developed to meet the requirements of offshore wind site assessment surveys. “It’s a ‘one-stop shop’ solution for the industry, allowing developers to get trusted vessels on the water and put to work as soon as possible,” SAFE Boats explains.

To start off, Merlin will be manned, with the Mythos AI control system serving as an advanced driver-assist system (ADAS), enhancing navigational safety by increasing the situational awareness of the onboard personnel. Features of the system’s ‘full perception suite’ include collision avoidance, ship system monitoring and wildlife detection. With crew on board, Merlin will be capable of a range of between one to five days.

Autonomous system

The builder continues: “Mythos AI solves the workflow challenges of hydrographic survey by enabling any qualified mariner aboard Merlin – or a remotely located hydrographer – to draw a box around the area to be surveyed on the Mythos AI charting display and instruct the boat to survey that area to spec.” The technology also makes it possible to ping bi-directional, real-time survey data between the vessel and remotely based hydrographers.

When engaged in wind farm site assessment surveys, Merlin will use a variety of scientific equipment, supplied by Echo81, to gather seafloor data, including: a sub-bottom profiler; dual-head, multibeam sonars; a towed side-scan sonar and magnetometers; a single-beam sonar; USBL; and a moving vessel profiler.

All hydrographic data collection and vessel navigation functions are combined on a singular graphical user interface (GUI). Remotely located hydrographers can also use the Mythos AI technology to monitor multiple AHSVs, “collecting data simultaneously in different regions or in formation,” SAFE Boats says. The builder continues: “The vessel will remain manned by skilled mariners while the Mythos AI technology collects and verifies datasets.”

It’s worth mentioning that Mythos AI’s autonomous system has been granted US Coast Guard approval for operations within congested inland waterways. “Because Mythos AI is currently training autonomous navigation in busy ports, it will quickly deploy robust autonomy in offshore environments which are significantly less complex,” SAFE Boats says.

In the future, though, this autonomous technology will pay a more prominent role in increasing the efficiency of data collection missions. “Eventually it will be possible to control the vessel from dock to dock completely unmanned, while manipulating critical data collection parameters such as the depth of towable sonar sensors,” SAFE Boats predicts. “Once the Mythos AI technology allows for unmanned operations, Merlin will increase survey productivity tenfold, by allowing 20-day survey endurance on a vessel half the size of manned vessels with similar survey capabilities.” When operating in autonomous mode, the crew aboard Merlin will still be able to regain manual control at any time, “using throftle or steering inputs, just as with modern autopilot systems”, SAFE Boats says. It will also be possible to remotely pilot the vessel, as connectivity permits.

Customisable interior

In terms of its general arrangement, Merlin has been designed specifically for offshore wind farm ops. “The hydrodynamic shapes of the hull and moonpool ensure that high-quality data can be collected for long durations,” SAFE Boats says. “The hull was specifically designed to incorporate the industry’s most advanced sonars with minimal interference while collecting data at a highly efficient pace.” And, with a relatively shallow draught of 1.6m, the vessel should be able to call at most US ports and harbours.

The att working deck has the capacity for 10tonnes of cargo, with dual tow winches and A-frame configured to optimise deck space for towable sensor payloads. A marine mammal observer post is located on the flybridge. For additional stability and crew/personnel comfort, Merlin is equipped with an active ride control system, supplied by Seakeeper, and the vessel will also carry a pair of 15-person inflatable life ratts. Stat-X supplied the boat’s fire suppression system, located in the engine compartment.

It will be possible to customise the AHSV’s interior to suit the operator’s requirements. At present, SAFE Boats reveals, the three-deck vessel’s interior includes: two large survey workstations; twin staterooms; a full bathroom, with secondary head; and a galley.

Just as importantly as its autonomous capabilities, perhaps, is Merlin’s alt-fuel arrangement. The vessel has been fitted with twin Volvo Penta D13 engines with IPS, allowing hybrid diesel-baftery operations. “Hydrogen and baftery storage will depend on individual customer requirements,” says SAFE Boats. To achieve truly emission-free output, however, Merlin can accommodate hydrogen technology provided by Zero Emission Industries (ZEI) – the company responsible for the hydrogen fuel cells aboard SWITCH Maritime’s San Francisco-based, 22m-long ferry Sea Change (see RINA’s Significant Small Ships of 2021).

While speed and range will vary depending on the power package selected, SAFE Boats estimates that preliminarily, with the current Volvo Penta set-up, Merlin will have a range of 2,500nm at 5knots. As of late April, the builder was yet to receive its first AHSV order, though did comment: “We have interested buyers that could expect first delivery by the end of 2024.

The vessel’s 1.6m draught will enable it to call at most US ports and harbours

The vessel’s 1.6m draught will enable it to call at most US ports and harbours

SAFE and sound

Founded in 1996, SAFE Boats International has come to launch more than 2,300 boats from its boatbuilding facilities in Tacoma and Bremerton, in the state of Washington. The builder’s output has included fireboats, patrol vessels and military craft, sized approximately 6m to 30m+, for a customer base spread across more than 60 countries.

Earlier this year, SAFE Boats transferred 100% of the company’s ownership to its 250+ employees, joining a small but growing band of Employee Stock Ownership Plan (ESOP)-accredited companies in the US: a share of approximately 6,500, accounting for almost 14 million employees. ESOPs enable employees to own shares in the business and benefit from the shares’ growth in value over time.



Length:                                 22.96m (oa), 22.8m (wl)

Breadth, oa:                        7m

Draught, max:                    1.6m

Displacement, max:          70tonnes

Deck cargo capacity:         10tonnes

Main engines:                     2 x Volvo Penta D1 (optional hybrid-system ready)

Propulsion:                          2 x Volvo IPS 1050

Service speed:                    15knots (80% MCR)

Max Speed:                        17knots (100% MCR)

Tank capacities

Fuel oil:                9,997litres

Fresh water:       999litres

Crew:                   6

Passengers:                                       10

Classification society:                      ABS


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