Robotics
Robotics revenues decreased $3.5 million, or 9%, in the first quarter 2022 compared to the prior quarter. The decrease in revenues was due to seasonally lower vessel, ROV and trencher activities during the first quarter 2022. Chartered vessel days decreased to 323 days during the first quarter 2022 compared to 419 total vessel days during the prior quarter, and vessel utilization decreased to 90% in the first quarter 2022 compared to 99% during the prior quarter. Vessel days during the first quarter 2022 included 136 spot vessel days performing seabed clearance work in the North Sea, compared to 237 spot vessel days, including 197 spot vessel days performing seabed clearance work in the North Sea and 40 spot vessel days completing the ROV support work for a telecom project offshore Guyana, during the prior quarter. ROV and trencher utilization decreased to 35% in the first quarter 2022 from 38% in the prior quarter, and trenching days decreased to 66 days during the first quarter 2022 compared to 90 days during the prior quarter. Robotics operating income decreased $2.0 million during the first quarter 2022 compared to the prior quarter due to lower revenues.
Robotics revenues increased $15.2 million, or 69%, during the first quarter 2022 compared to the first quarter 2021. The increase in revenues was due primarily to higher vessel and ROV activities year over year. Chartered vessel days increased to 323 total vessel days during the first quarter 2022 compared to 165 total vessel days during the first quarter 2021, although vessel utilization was flat at 90% in both the first quarters 2022 and 2021. Vessel days during the first quarter 2022 included 136 spot vessel days performing seabed clearance work in the North Sea, compared to three spot vessel days during the first quarter 2021. ROV and trencher utilization increased to 35% in the first quarter 2022 from 24% in the first quarter 2021, although trenching days decreased to 66 days during the first quarter 2022 compared to 72 days during the first quarter 2021. Robotics generated operating income of $1.5 million during the first quarter 2022 compared to operating losses of $2.9 million during the first quarter 2021, an improvement of $4.4 million, due to higher revenues year over year.
Production Facilities
Production Facilities revenues decreased $1.8 million, or 9%, in the first quarter 2022 compared to the prior quarter primarily due to a decline in oil and gas production volumes. Production Facilities revenues increased $1.8 million, or 11%, compared to the first quarter 2021 primarily due to higher oil and gas prices.
Selling, General and Administrative and Other
Selling, General and Administrative
Selling, general and administrative expenses were $14.4 million, or 9.6% of revenue, in the first quarter 2022 compared to $21.5 million, or 12.7% of revenue, in the prior quarter. The decrease was primarily due to lower employee incentive compensation costs.
Other Income and Expenses
Other expense, net was $3.9 million in the first quarter 2022 compared to $0.1 million in the fourth quarter 2021. Other expense, net in the first quarter 2022 included unrealized foreign currency losses related to the British pound, which weakened approximately 3% during the first quarter 2022.
Cash Flows
Operating cash flows were $(17.4) million during the first quarter 2022 compared to $18.9 million during the prior quarter and $39.9 million during the first quarter 2021. The decrease in operating cash flows quarter over quarter and year over year was primarily due to lower earnings, higher regulatory recertification costs for our vessels and systems and negative changes in net working capital during the first quarter 2022. Regulatory recertification costs for our vessels and systems, which are included in operating cash flows, were $10.3 million during the first quarter 2022 compared $2.5 million during the prior quarter and $1.8 million during the first quarter 2021.
Capital expenditures totaled $0.6 million during the first quarter 2022 compared to $0.9 million during the prior quarter and $1.3 million during the first quarter 2021.