[Tallguy]

If the sub was on the surface then he was not the more maneuverable vessel. Think about it. Submarines do not have a keel & so they have some directional instability while cruising surfaced.

There was another collision involving a surfaced sub a few years ago. The sub was cruising a parallel course while re-supplying from a large supply ship. The 2 vessels bumped when the sub side-slipped into the larger vessel.

Not enought to go on in this story, but if they were surfaced I could see this happening very easily.

[AndyJackson]

If the sub was on the surface then he was not the more maneuverable vessel

Yes he was. By far, hands down, no questions about it. He was also supposed to be smarter than that. Even if the CO of the amphib ship tried to ram the sub deliberately he should not have been able to do so.

[AFreeBird]

Hadn't thought about lateral slippage. Good point. A subs keel, or centerboard, is on the top, and doesn't do squat unless submerged..