Operator states during his transit that sea state was increasing as they exited the channel.  A few waves hit the vessel damaged the drop clear view curtains, exposing them to the elements.  They put their life jackets on and proceeded to return to port.  The vessel was becoming more sluggish and a distress call was placed to USCG.  Soon after call they lost power to both engines.  The vessel then was swamped over the stern.  They had to abandon the vessel and swam away as the vessel sank.  A passing vessel assisted them and transported them back to port.  Total loss of vessel.
Martha's Vineyard             