RedactedNarrative: Vessel was westbound around 15 mph and about 50 yards north of the port of indiana breakwall when it struck a submerged pipe.  The collision ripped the lower outdrive from the boat, rendering it completely disabled in the water and taking on water.  Both the operator and passenger put on pfd's and waved to a nearby boat for help.  The boat that approached was from m.c.m. marine, the company that is doing the dredging near the port of indiana.  The operator of this boat (name unknown at this time) apologized for the accident and said that they were floating the dredge pipe to move it.  This worker for mcm stayed with the disabled boat until cms marine came to tow the boat in.  Uscg out of michigan city also arrived, but after determining that everyone was ok and the boat was in the process of being towed, left to handle another incident.