PORTLAND — The city’s fireboat left Portland this morning, headed to Rockland for repairs.

The fireboat sustained nearly $40,000 in damages when it hit an underwater object during what city officials said was a training run around sunset on Oct. 15. A subsequent investigation by the fire chief determined the accident could have been avoided and the two-person crew did not follow proper procedures.

The firefighter at the controls of the City of Portland IV was suspended for three days without pay and the fire captain aboard the boat was suspended for 10 days without pay.

The investigation also determined that a dozen civilians, including family members of the captain, were on the boat at the time of the accident. The two firefighters were not disciplined for that because the city has no policies barring guests on the boat.

Nicole Clegg, Portland’s spokeswoman, said the boat left this morning. She said she didn’t know if city employees were piloting the boat, but said it left under its own power.

One of the boat’s two shafts was sheared off in the collision and a propeller and the rudder were damaged. Repairs are expected to take two or three days. The boat is insured, but the city will have to pay a $25,000 deductible for the repairs.