Sub physics - experts needed

[Bubblehead Nuke]

Originally Posted by MarkShot

Well, actually, I think operation with ballasts and air probably isn't that different than WWII. So, I was posting interesting here. Also, leading to interesting additional comments from some of the nuke service vets.

Mmm.. baiting someone??

(1) We've heard the sequence "green board" and "pressure in the boat". The green board as everyone knows is that all external openings are sealed up. "Pressure in the boat" - once sealed, air is bled into the boat and the diving officer makes sure that the pressure remains constant as this done as a final test that the boat is truely tight before he takes her down.

A nuke boat has only 4 main people sized passages to the outside enviroment. When you 'rig for sea/rig for dive' there is a checklist that you have to go thru before you can dive. By the time you have left the pier, you know that the aft escape trucks and the weapon shipping hatch has been secured/rigged properly. When the linehanders come down, they do the rig for dive checklist and close out the forward escape trunk. This leaves just the hatch to the bridge. This will not be closed out till just before the dive but as it is just one hatch it is not all that big a deal time wise.

One reason they put a pressure on the boat was to make sure that the major hull opening were indeed shut. You have the various ingress/egress hatches (and a LOT of those) plus the main air induction for those BIG engines. There are a lot of valves on a diesel boat that can kill you quick if an electrical indication switch was to stck in the wrong position or a seal was not in the greatest shape.

Unlike the diesel boats of yore, nukes do not have the huge problem of equalizing the air pressure inside the boat with the outside. In the old days, you could have a pretty good pressure built up and if you 'popped the hatch' it could fling the hatch open and pop you right out with the sudden air movement. The reason for sealing themselves in the conning tower was to limit the amount of air that could be expelled due to a positive pressure thus not explosively tossing someone over the side and/or possibly damaging a watertight hatch while doing it. They had to get topside FAST and make sure that it was safe for surface running. Then the rest of the boat could equalize as they opened the air valves for the main engines and lined up for external ventilation.

Things like stright board are still used as a quick indicator of the the status of the major hull openings, but procedures and knowledge control a lot of the little things that can get you in trouble. Besides, the little valves will make one heck of a mess but not sink you real fast.