US-listed Capital Product Partners (CPLP) has doubled the size of its LNG carrier fleet, exercising options to buy three newbuildings following a successful bond sale in its home country of Greece, which financed part of the acquisition.

The $623m purchase of the 174,000-cbm vessels will be financed through about $168m in net proceeds from the bond issue, $439.4m in sale-and-leaseback financing debt, as well as $15.7m cash at hand, CPLP said in its earnings release late on Thursday.

CPLP's fleet primarily consists of containerships. Its expansion into LNG carriers through newbuildings originally ordered by Capital Gas — a company controlled by CPLP sponsor Evangelos Marinakis — is boosting its secured earnings.

CPLP's contracted revenue, including options, surged to $1.95bn at the end of the third quarter from $625m, said CPLP chief executive Jerry Kalogiratos.

"The acquisition of all six LNG carriers is expected to be highly accretive to earnings and distributable cash flow per unit," he said in the earnings release, adding that the company would "further diversify" its revenue sources and customer base.

Following a sale of the 9,288-teu containership Adonis (built 2015) during the fourth quarter of the year, CPLP will have a fleet of 21 vessels, consisting of 14 boxships, six LNG carries and one capesize bulker.

A bigger fleet helped CPLP boost earnings in the third quarter. Net income increased by 53% year-on-year to $11.9m, while revenue jumped at an annual pace of 21% to $43.1m.

In the nine months through September, net income more than doubled to $58.2m, helped by rising revenue and gains from the sale of the 9,288-teu MSC Brittany (ex-CMA CGM Magdalena, built 2016).