British Rail and the Royal Navy were holding separate inquiries into how a 425-ton minehunter and a passenger ferry collided in the entrance to Portsmouth Harbour.
Ratings on the stern of the Royal Naval Reserve minehunter, Thames, scrambled to safety as it collided with the British Rail Isle of Wight ferry, MV Southsea.
No injuries were reported but both ships suffered slight damage.
D James, a passenger on the ferry said: ‘We could see the collision developing.
‘The sailors on the Thames ran clear as we got closer.’
He said Southsea sounded its siren before the ships collided.
British Rail’s Shipping Services manager, LHR Wheeler, said Southsea, which was approaching its berth at the Portsmouth Harbour station jetty at the end of a Solent crossing from Ryde was allowed to continue its scheduled services after an examination.
Thames, which was about to berth at HMS Vernon, continued its duties after a similar examination.
The accident was the second in Portsmouth Harbour involving a British Rail operated ferry that week.