The board also ruled that inadequate training and experience aboard HMCS Corner Brook were contributing factors in the accident.
Navy Capt. Luc Cassivi says the incident was avoidable, adding those aboard the submarine failed to account for the vessel's actual position.
The accident took place during a June 4 training exercise in Nootka Sound, which is north of Tofino, B.C. and west of Campbell River.
A navy news release says the submarine struck the southeastern wall of Zuciarte Channel because it was southeast of its intended position.
The navy says nobody was seriously hurt in the accident and the cost of the damage will be confirmed during the submarine's maintenance cycle.