Feasibility of Seakeeping, Cost and GHG Efficiency of <24m SWATH design for ROV deployment

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Innovate UK
Innovate UK
Innovate UK
Innovate UK
Innovate UK

£1,016,525

Jan. 1, 2023

Aug. 31, 2023

Offshore critical national infrastructure, such as subsea cables and wind farms, requires increasing asset integrity inspections to ensure safe operations, and decrease downtime through preventative maintenance. Annual Offshore Windfarm subsea inspections costs are estimated at £18m/yr per 1GW (£900m @50GW anticipated by 2030 in UK; Crown Estate). Given that by 2028 20% of the 69GW operational fleet will be more than 10 years old, inspection and services of OSW is expected to grow rapidly.

Subsea inspections require launch and recovery of Remote Operated Vehicles (ROV) from an offshore platform which is subject to variable seastate conditions. Current vessel designs are inefficient E.g. to increase operational inspection time, companies deploy larger vessels which offer a more stable platform in large sea states, but consume 10-50m3/day of diesel (39.6-132tCO2/day). Operators are investigating smaller uncrewed solutions. However these smaller platforms are restricted to operating in seastates <3-4 force max, with significant wave height <1.5m. In the UK this would limit operations from May-Aug, with operational time <50% (~61days). This is unviable commercially if we are to increase offshore wind whilst reducing the levelized cost of energy.

ACUA Ocean (AO) through Clean Maritime Demonstration Competition 1 (CMDC1) designed a small waterplane area twin hull (SWATH) hydrogen powered vessel with a focus on marine monitoring and protection. SWATH vessels have an intrinsic increased stability, as a rule of thumb SWATH vessels offer a seakeeping performance equivalent to monohull vessels 15x the gross tonnage. Therefore, AOs 21t SWATH vessel has a theoretical seakeeping performance of a 300t monohull vessel making it a significantly more efficient whole-ship design.

During this feasibility study, AO and SMMI aim to conduct a wave tank test of the vessels seakeeping capabilities to simulate ROV payload deployment and recovery operational limits. A successful demonstration and simulation of a wave tank testing would demonstrate the capability of AOs vessels and would enable AO and end customers to accelerate the development of a commercial ROV deployment system from small SWATH and expand the AOs capabilities to new applications and use cases, opening up new commercial and geographical opportunities within a rapidly growing ORE and offshore infrastructure markets.