(AP) — An expert sea pilot has testified before a federal agency that he is concerned that cruise operators, like airline pilots, may rely too much on electronics to navigate massive ships, losing the knowledge and ability to manually operate a vessel during a power failure.

Capt. Jorge Viso with the Tampa Bay Pilots testified Wednesday before the National Transportation Safety Board. The agency is holding a two-day safety hearing after several high-profile cruise mishaps that left thousands of passengers stranded for days in squalid conditions.

Viso says he fears cruise ship captains handling high-tech vessels with state-of-the-art navigation equipment are not as adept at manually handling the massive ships as they should be. He also says that while cruise ships are continuously getting larger, port infrastructure is not keeping up.