PORTLAND – Two chief engineers have been sentenced to two years probation and fined $3,000 each for hiding the overboard ocean dumping of waste oil from their cargo ship, the Department of Justice said.

Alfredo D. Lozada and Felipe B. Arcolas worked aboard the M/V Kent Navigator when the U.S. Coast Guard received an anonymous tip that it was illegally discharging its waste oil and bilges at sea while bound for Portland.

After the ship arrived in port, a Coast Guard investigation revealed that Lozada and Arcolas directed the ship’s crew to discharge waste oil and bilge tanks directly overboard in the middle of the night while at sea, prosecutors said.

The pair was accused of creating a false record book to make it appear as if the discharges were made using required pollution control equipment as required by law. They also were accused of making false statements to the Coast Guard.

U.S. District Judge D. Brock Hornby on Thursday ordered that Lozada and Arcolas spend the first month of their probation confined to their temporary residence in Portland where they have lived since they were removed from the ship last summer.