I was digging around in our Commandant's Instruction Manual (guidance for everything Coast Guard) and found the Abandon Ship Procedures. Though they apply specifically to our methods and whatnot, I'm sure it's relevant to anyone forced into a mass abandonment of a large vessel due to some sort of at sea casualty - fire, flooding, collision, explosion...

RESCUE AND SURVIVAL SYSTEMS MANUAL
United States Coast Guard
COMDTINST M10470.10E
Appendix A - Abandon Ship Procedures

Introduction
This appendix presents procedures to successfully abandon ship safely. Cutter crewmembers shall become thoroughly familiar with the information presented and be mentally and physically prepared to abandon ship if required.

Exiting The Ship
If possible, personnel should get away from the ship in a lifeboat or life raft. Personnel should lower themselves into the water using a firmly attached line or hose. When a choice is available, personnel shall leave the ship from the windward side and from whichever end of the ship is lowest to the waterline.
NOTE For optimum survival, personnel leaving the ship shall be fully clothed.

Entering The Water
If it is necessary for personnel wearing a PFD to jump into the water, they must hold their legs together and keep their body erect. Personnel wearing a survival suit should cover their face with one hand, hold the crotch of the suit in place with the other and cross their legs when entering the water. Before lowering injured personnel into the water, always adjust the leg straps properly.

Jumping Into The Water
Securely fasten inherently buoyant PFDs and keep them close to the body by folding the arms across the chest and gripping the jacket with the fingers. This procedure prevents buoyant PFDs from riding up and striking the chin or neck when the wearer hits the water. If an inflatable PFD is being worn, do not inflate it until the wearer is in the water. Use the same procedure for jumping with an inflated PFD as with the inherently buoyant PFD.

Inflation
The wearer shall inflate the PFD as soon as they are in the water and clear of flames or debris.

Swim Away
When in the water, survivors shall swim away from the ship as rapidly as possible and, if available, climb into a lifeboat or liferaft.

Underwater Explosions
If underwater explosions occur in the vicinity, survivors shall swim or float on their backs, keeping their heads and chests as far out of the water as possible. Underwater explosions are particularly threatening to lungs, abdomen, sinuses, and eardrums.

Abandonment
When the ship is entirely surrounded by burning oil and abandonment is essential, personnel shall jump feet first through the flames and swim windward under the surface of the water for as long as possible. When air in the lungs is exhausted, the swimmers should spring above the water in a vertical position, push the flames away with a circular motion of the hands, quickly take a deep breath with their backs to the wind, submerge feet first in a vertical position, and swim under the surface again.

Minimize Buoyancy
Discard any buoyant articles of clothing or shoes. Whenever possible, personnel should wear only the inflatable PFD during this procedure for abandon ship, and should inflate the preserver only after the person is clear of the flames. Inherently buoyant PFDs will not permit the wearer to swim beneath the surface. Therefore, do not wear them before leaving a ship surrounded by flames.