The incident occurred at about 08:00 in Falmouth harbour, according to the Daily Mail. Nobody was injured as a result of the incident.
According to reports, a Ministry of Defence spokesman confirmed that a vessel under contract with the department was involved in the collision.
The ship is a range safety and training vessel run by Smit International, under contract with the MoD, according to the Navy campaign group NavyLookout.
Police were called to the site of the incident and have started an investigation.
