Further Irresponsible Speculation on the Cheonan Incident

Some thoughts:

• If Cheonan struck a mine, and the mine was recently laid (or recently released from its mooring) what kind of message was North Korea trying to send? Even if the North Koreans had relatively good information about Cheonan's patrol area, it's hard to imagine that they could have been optimistic that the release of one mine (or perhaps even a very few mines) would actually result in the destruction of a South Korean ship. The ocean is a big place; if Cheonan struck a mine, it must have been pretty lucky. Alternatively, the North Koreans could have laid an entire field or set a large number of mines adrift, but you'd expect then that there would be some evidence of North Korean activity, not to mention a considerable number of remaining mines. Is there any indication that the rescue effort has taken the threat of additional mines in the area very seriously?
• I still don't find the human torpedo idea very compelling. The literature indicates that North Korean human torpedoes travel very slowly (2km/hour) which would make it extremely difficult to use them on a target moving at any speed at all. Even if a North Korean mothership released the human torpedo in Cheonan's expected patrol area, the Norks would have to be extremely lucky to be in plausible attack position at that speed.
• There continues to be some confusion as to whether Cheonan opened fire before or after the explosion. If after, there are two relatively coherent explanations; either the crew fired on a legitimate North Korean target, or they were so panicked that they misidentified a contact and opened up anyway. If before, it seems more likely that they were firing at a Nork target, unless somehow the process of opening fire precipitated the accident. I'm not familiar with the layout of Cheonan, but this doesn't seem very likely; would an ammunition handling accident have caused an explosion in that part of the ship?

All of this remains speculation, and I do invite those better educated than me (most of the readers of this blog) to correct any misconceptions. At this point, though, the (non-human) torpedo explanation still makes sense to me, and perhaps more sense than the alternatives.