SEASPAN, a Hong Kong-based non-operating containership owner, has posted a 52.9 per cent year-on-year net profit increase in 2015 to US$199.3 million, but revenue figures were not clearly stated.

On revenue, Seaspan CEO Gerry Wang would only say: "Seaspan achieved strong revenue and earnings for the year and fourth quarter. We continued to enter into fixed-rate long-term contracts with high creditworthy counterparties, ending the year with future contracted revenues of nearly $6 billion.

"During 2015, we achieved an important milestone by growing Seaspan's operating and managed fleet to over 100 vessels, complementing our successful execution of the company's stable and predictable business model. With the delivery of two 10,000-TEU class and six 14,000-TEU class state-of-the-art containerships in 2015," Mr Wang said in a statement.

During the fourth quarter of 2015, Seaspan accepted delivery of one 14,000-TEU ship, the YM Warmth, expanding Seaspan's operating fleet to 85 vessels. The YM Warmth was built at Hyundai Heavy Industries.

At the beginning of 2015, Seaspan had 77 vessels in operation. Seaspan accepted delivery of eight newbuilding vessels during the year, bringing its operating fleet to a total of 85 vessels at December 31.

Vessel utilisation was 97.9 per cent for the fourth quarter and 98.5 per cent for the year compared to 98.7 per cent for the quarter and 99.0 per cent in 2014.

Ship operating expenses increased 16.7 per cent to $193.8 million for the year. Seaspan expects ship operating expense to continue to increase as its fleet expands and ages and as the average size of its vessels increases.