Construction launches on US offshore wind’s first mini CTV

US offshore vessel operator, builder, and owner Edison Chouest Offshore (ECO) has launched construction of the US offshore wind industry’s first mini crew transfer vessel (CTV), designed by the UK’s Chartwell Marine.

Set to begin operating in summer 2024 for offshore wind company Ørsted and its US-based joint venture partner, Eversource Energy, the crew transfer vessel will simultaneously accompany the launch of ECO Edison, the first ever American-built service operation vessel (SOV). The CTV – known as the ‘daughter craft’ onboard the SOV – can be deployed to manoeuvre crew across the Revolution Wind, South Fork Wind, and Sunrise Wind offshore wind farms in the Northeast US, under development by the joint venture.

Building commenced in July 2023 at Edison Chouest’s Louisiana shipyard, drawing components from US suppliers, and using Chartwell’s design from its expanded range of offshore wind support catamarans — which has seen orders from across Europe, Asia, and the USA.

Chartwell’s design responds to the increasing demand in the US offshore wind market for low-emissions, cost-effective support vessels, with the catamaran’s optimised hull form offering efficient fuel use as well as stability and manoeuvrability in choppy waters, says ECO. A first for this vessel type, the Volvo Penta IPS (integrated propulsion system) provides high power and performance as well as onboard comfort for operators. The system allows for a wide number of optional features and functions, featuring forward-facing, twin counter-rotating propellers with an individually steerable IPS under the hull.

Chartwell conducted model testing in January 2023 to simulate and adapt to the specifications of the wind turbines that will be installed at the Northeast US project sites.

“This vessel is the small but essential chain connecting SOVs and turbines together,” says Andy Page, MD Chartwell. “Engineers need to safely transition from larger vessels to turbines quickly and safely, and we set out to design an agile and streamlined vessel that has both bases covered.

“But it’s not a one-size-fits-all. Turbines come in different configurations, with different requirements for effective crew transfer. That’s why we collaborated with Ørsted to thoroughly test and tweak our design to the joint venture portfolio’s particular needs.”

“We are proud to partner with Edison Chouest and Chartwell Marine to accelerate the transformation to a new clean energy future,” says Mike Ausere, VP of business development at Eversource Energy. “These vessels represent the incredible power of offshore wind to create American jobs in the industries of the future, deliver clean, renewable energy, and establish a US-based supply chain that will benefit workers and communities for generations yet to come.”

In January 2023, Chartwell Marine announced it had been awarded a £320,000 Innovate UK Smart Grant to test the feasibility of a methanol-fuelled vessel design – said to be a market-first.