It sounds like the young swiftboat sailors might have not been carefully going from point A to point B.
I can't cut and paste - because the NYT somehow makes that impossible. But after saying that the course they were suppose to take would course mapped in advance to avoid Iranian water, a "Navy officer" said - "Look, these are kids riding around in cool cammy (camouflaged) boats." It then speaks of senior Pentagon people expressing dismay - as details come in. They said that it seems that the guys and the gal were not good mariners. It also said they went in pairs.
Reading between the lines - it sounds like they might have been racing around on a beautiful Mediterranean day and they were not paying attention that they entered Iranian water. (From the maps shown, there is territorial water around the small island owned by Iran that their Navy used.) Regardless, they are very very lucky that Kerry had that relationship with Zarif!
Now, obviously JK's time on the swiftboats were different as there was some real probability that he could be killed or seriously maimed any mission he went out on -- and he was not your average person. However, remembering the films he made of the swiftboats going through water when they were NOT in the dangerous channels - I would bet that the MA sailor in him might have when not in danger enjoyed the speed of the boat himself!
link - http://www.nytimes.com/2016/01/14/world/middleeast/iran-navy-crew-release.html?_r=0