The AMHS dock in Skagway sank overnight. (Photo courtesy Alaska Department of Transportation and Public Facilities)The Skagway ferry terminal dock is fully submerged, according to state transportation officials.Download AudioDOT spokesman Jeremy Woodrow says an engineer is on his way to Skagway to find out what happened. Apparently the dock started to sink overnight and by early this morning it was totally underwater.The 160 foot by 120 foot dock is about 12-feet deep. It is made of 24 individual concrete chambers.“The words that the engineer used is he’s perplexed,” Woodrow says. “We actually have inspected everyone of those individual chambers in the last year and there was no indication of any wear.”Woodrow says the cause of the collapse remains a mystery until an engineer gets on site and a diver gets an underwater look.No ferries are scheduled into Skagway today (Thursday), but the LeConte is to sail there tomorrow. Woodrow says marine highway officials are working out a plan.This is a breaking story. Check back for details.Note: Previous reports indicated the dock had collapsed. That connotes structural failure and DOT’s Woodrow says the extent of the damage is still unknown.