Earnings took a hit at Sembcorp Marine in the fourth quarter after reduced business volume made it harder to absorb overhead costs.

The offshore and marine giant recorded a net loss of $33.78 million for the three months to Dec 31 , reversing the net profit of $34.29 million recorded a year earlier.

Turnover was 21.1 per cent lower at $654.95 million, mainly due to lower revenue recognition for rigs and floater and offshore platform projects.

The firm did turn in a full-year net profit of $14.08 million while revenue was down by 32.7 per cent to $2.39 billion.

Excluding the effects of the sale of nine jack-up rigs to Borr Drilling and the termination of five jack-up rigs with two customers during the year, turnover would have decreased by 28 per cent.

Additional cost accruals made in the final quarter for floater projects, which are pending finalisation with customers, did not help either.

But the impact was partly offset by a gain on disposal of SembMarine's stake in Cosco Shipyard Group Co completed in January last year and a gain on deemed disposal of available-for-sale financial asset that arose from the group's step-up acquisition of Gravifloat AS.

There was also a much smaller share of losses of associates and joint ventures in the full year - down to $3.62 million, which was 89.7 per cent lower compared with $35.13 million a year earlier.

SembMarine has already received an upfront payment of US$500 million (S$660 million) from Borr Drilling towards a deal pegged at US$1.3 billion, plus a market-based fee for the sale of nine jack-ups.

Earnings per share for the full year were 0.67 cent compared with 3.77 cents a year earlier.

Net asset value per share was 118.69 cents as of Dec 31, down from 122.62 cents as of Dec 31, 2016.

President and chief executive Wong Weng Sun said the remaining US$800 million will be paid within five years from the respective rig delivery dates.

Separately, SembMarine entered into another agreement in December to sell the semi-submersible West Rigel for US$500 million.

SembMarine has also sought to further diversify its revenue stream last year from rig-building and oilfield development projects.

Its repairs and upgrades unit performed a total of 390 dry dockings, with revenue per vessel surpassing the year before on higher-value works and improved vessel mix.

With activity picking up for non-drilling projects, SembMarine is revisiting capital expenditure planned to bolster its capabilities to deliver orders. Mr Wong said capex, which stood at $178 million for last year, is now expected "to trend slightly upwards", particularly on the development of the Tuas Boulevard Yard "in response to business needs".

The directors have recommended a final dividend of one cent a share.

SembMarine shares closed flat at $2.63 yesterday.