Blue Fin has filed suit against German bunkerer Bomin alleging they sold bad fuel, running up a $1m-plus bill for the shipowner.

In a lawsuit filed in Connecticut federal court, the Heidmar-controlled tanker pool says the 164,626-dwt Ridgebury Alina L (built 2001) stopped to get fuel in Port Louis, Mauritius, en route to Singapore from the Bahamas last July.

Lawyers allege that Bomin filled the tanker with "off-spec" fuel, despite knowing the fuel was bad and didn't tell Blue Fin until after the delivery was completed. Bomin, the lawsuit claims, then came back to Blue Fin and told them testing had proven the fuel was fine.

"The price of the cargo being shipped by the charterer on board the vessel was dependent on the vessel arriving in Singapore on time. As such, the charterer faced substantial damages if the vessel was delayed," the complaint reads, noting Blue Fin would be liable for any damages resulting from delays.

Still, the Ridgebury Alina L had to stop in Sri Lanka to get more fuel, adding six days to the voyage and costing Blue Fin more than $364,000 and damaging the ship's fuel system.

The cargo, the lawsuit said, lost more than $658,000 in value.

Bomin did not return a request for comment.