Robby -- check Sam's cross section drawing above. Note that the outboard margin plates of the tanks are almost normal to the hull, but angle sharply inboard toward as the go upward to meet the tank top which supports the firemen's tunnel. Any thrust diagonally upward -- such as from a grounding -- would be transferred along these margin plates to the structure above. Lots of things could result. The structure could have been strong enough to resist any loss of integrity from the iceberg. Or, at the opposite end of the scale the tunnel could have been ruptured right along toward bulkhead D. And, there are as many possibilities in between to account for just about any theory of how water got into the tunnel.
The place of maximum vulnerability is the stair tower encasing the two spiral ladders. These ladders were set about halfway outboard P&S of the tunnel walls, probably to give maximum room for men entering and exiting the ladders during change of watch. It is the outermost area of the stair toward which is most likely to have failed in Garzke's scenario.
One "fooler" in Sam's drawing is the shape of the iceberg. I'm not saying that Sam was incorrect about that, just we don't know anything about the face presented to Titanic.. For Garzke's idea to work best it the thrust from the iceberg has to be virtually in line with the margin plates. The conventional sideswipe would prevent the sort of damage he envisions. A true grounding on the bottom would lessen the force transmitted to the stair tower and make Garzke's idea less plausible. But, we don't know the shape of the berg at the area of the hull in way of that tower. So, all we can do is add Garzke's concept to the pile of plausible possibilities.
My view is that the description of the flooding is of relatively new ingress. The tunnel is not filled and it is possible to see water running under force. Neither of these would be visible nearly 20 minutes after impact on the iceberg simply because the area should have been flooded to deeply. There would have been some swirls on the surface, but otherwise the situation would have been a lot less exciting than what Hendrickson described. This is one case where less obvious ingress indicates greater damage done earlier than spurting water done close to the time of its discovery.
Something else. While Hendrickson gives an exciting account of that water, it does not seem to be comin in under 30-odd feet of head pressure. I've not fought a leak that deep in a hull. My experience with a fitting one-third that deep tells me that a 1.5-inch opening will teach the hardest bitten seaman how to pray faster than a convent full of nuns. Gob smacked is the only term you can use in public.
I'm also intrigued by Hendrickson meeting engineer Hesketh not in the boiler room, but somewhere near the head of Scotland Road on E Deck. Given that boilers needed to be made safe and fires to be raked, it seems odd that an engineer would be so far from the critical action. And, when Hesketh made his report it was as if the engineer already knew about the flooding. Instead of asking to be guided to the flooding, instead the engineer told Hendrickson to go get lamps for the boiler rooms which were dark because of a power failure.
To understand the Hesketh/Hendrickson interaction, we have to delve into possible motives for the engineer's lack of interest in the flooding of the tunnel and his overriding need for oil lamps.
Darkened boiler rooms are difficult to dangerous places to work. So, lamps would be a necessity. But, why would an engineer have gone to E deck to find men to fetch them? He could -- and probably should -- have delegated a leading stoker to do that job. However, of far more importance would have been operation of the valves controlling the bilge pump intakes. Duplicates of valves down on the tank top level were placed on E deck. This allowed them to be opened or closed even if the compartmant were flooded. Adjusting these valves would normally be done under the direct supervision of an officer.
There were two 3 1/2 inch suctions in the tunnel.
My addition to the pile of plausible possibilities is that somehow a wrong valve was opened and water gravitated into the tunnel through the bilge piping system. Hesketh wasn't worried because he had either taken care of the problem or know about it was was about to have his working party close that valve.
-- David G. Brown
PS -- At this point in the discussion somebody always asks about a rupture of the FW tank whichstradled the tunnel in way of bulkhead C. As far as I know, nobody tasted the floodwater to find out if it was sweet or salt.