Revenue
Revenue increased by 7.5% for the quarter ended March 31, 2013 over the same period for 2012. This is due primarily to the impact of a full quarter's contribution of the larger newbuild vessels delivered in 2012 that have higher time-charter rates. These increases were partially offset by an increase in unscheduled off-hire which includes 221 off-charter days for four of Seaspan's 4250 TEU vessels, fewer days in 2013 due to leap year and lower rates for four vessels which were on short-term charters during the quarter. The increase in operating days and the financial impact thereof for the quarter ended March 31, 2013 relative to the corresponding period in 2012, is attributable to the following:
Quarter Ended March 31, 2013 --------------------------------- Operating Days $ impact impact (in millions) --------------- -----------------Full period contribution for 2012 vessel 320 $ 17.9 deliveriesChange in daily charterhire rate and re- - (1.7) chartersFewer days due to leap year (61) (1.7)Scheduled off-hire 44 1.1Unscheduled off-hire (223) (4.3)Other - 0.2 --------------- -----------------Total 80 $ 11.5 --------------- ----------------- --------------- -----------------
Vessel utilization was 96.1% for the quarter ended March 31, 2013, compared to 99.1% for the comparable period in 2012. The decrease in vessel utilization for the quarter ended March 31, 2013 was primarily due to a 223-day increase in unscheduled off-hire which includes 221 off-charter days for four of Seaspan's 4250 TEU vessels. During the quarter ended March 31, 2013, there were no scheduled dry-dockings, compared to the quarter ended March 31, 2012, where Seaspan completed four dry-dockings which resulted in 44 days of scheduled off-hire.
Seaspan's cumulative vessel utilization since its initial public offering in August 2005 through March 31, 2013 was 99.0%.
Ship Operating Expense
Ship operating expense for the quarter ended March 31, 2013 increased by $3.0 million, or 8.7%, to $37.5 million compared to the corresponding period in the prior year. The increase is due to 320 more ownership days related to the addition of four 13100 TEU vessels during the first and second quarter of 2012. In addition, larger TEU vessels are more expensive to operate. The increased cost of lubes, insurance and other operating costs associated with these vessels further contributed to higher ship operating expenses.
Ship operating expense for the quarter ended March 31, 2012 included fixed, daily, per vessel fees totalling $9.3 million, paid to Seaspan Management Services Limited (the "Manager") for technical services prior to Seaspan's acquisition of the Manager on January 26, 2012, and $25.3 million of direct costs incurred during the post-acquisition period from January 27 to March 31, 2012.



