Think I read a story couple days after this which claims the submarine was in fact a cigarette boat sitting very low in the water with some kind of rigged up exhaust/snorkel. Semi submersible at best. Iranian Navy and/or Pasadran militia use some kind of semi-sub speedboat that can reach 40kts and dive to a couple feet (not at that speed maybe).

Edit: Shame to waste this as a drugs runabout, but may be the ultimate … same guys do faster things though
http://www.youtube.com/watch?v=KMsUXUQx-XI