PORTLAND, Maine — After deliberating for about 16 hours in the manslaughter trial of a Massachusetts boater, a Portland jury has asked the judge for the definition of “deadlock.”

That suggests the jury might be at an impasse on some of the counts, but Justice Robert Crowley asked jurors to resume their deliberations. Robert LaPointe of Medway, Mass., faces two counts of manslaughter, two counts of aggravated drunken driving and reckless conduct with a dangerous weapon.

Prosecutors say he was drunk and recklessly speeding across Long Lake at night when his 32-foot speedboat collided with a smaller boat. The defense contended LaPointe didn’t see the 14-foot boat because it was black and had its lights off.

Killed in the collision on Aug. 11, 2007, were Terry Raye Trott of Harrison and Suzanne Groetzinger of Berwick. LaPointe and his passenger survived.