GPS is nothing but one tool on the bridge and should NEVER EVER be used as a primary means of navigation.
When navigating in confined waters, GPS should be used as a backup and as a secondary tool. The navigation team needs to be taking visual fixes, soundings, radar fixes, and then using GPS to help verify.
Having been on two ships with ECDIS there is lag associated with displayed position, and especially in confined waters it is a big no no to be using it. THere are a lot of problems with relying on ECDIS... has it been updated with all the Notice to Mariners, new obstructions, buoys or navigation marks moved or no longer in existance? A chart that is properly maintained is a far more effective tool than a computerized map that can become outdated very easily.
Also buoy hopping ie illegal. Buoys can be moved or knocked out of place by ocean conditions or by a ship hitting them, they are only anchored to the ocean floor.
Also when coming into port, if a ship is using a pilot it is still the captain's responsibility to ensure safe navigation of the ship.
BRM... we us it in the merchant industry and is just a take off CRM. Use all personnel and resources on the bridge.
Also having a screwed up gyro is no excuse. It should always be checked before entering and leaving port. Azimuths and amplitudes while out at sea and for in port, just check the true direction the ship is facing while at the pier.
Training:
I don't know the extent of the training the Navy gives one before being allowed to take the conn, but here is what it takes to earn a license to take the watch as a 3rd mate at my school. While it can be different for other schools, it's really about the same as its required by the Coast Guard.
300+ days at sea as a cadet, 13 hours at the helm of the ship, 13 weeks in the simulator, and 4 years worth of classes before my class was given the keys to a ship as a 3rd mate. While I may not be sailing on my license my classmates are and some are on ships where the watch only consists of them and an Able Bodied Seaman who acts as lookout and helmsman.
I'll hop off my soapbox now.
PS: In the merchant industry the Navy is considered a joke when it comes to navigation skills