RedactedNarrative: Operator #1 stated to the effect:
  
  I was cruising at approximately 15 - 20 knots when I heard and felt a loud bang.  I shut the engine off because I thought I had hit a sandbar.  I opened the engine hatch and saw water coming into the bilge.  I turned the bilge on and tried starting the motor again.  The engine started but when I gave it forward throttle nothing happened.  TowBoat US was on scene assisting another boat nearby.  SeaTow was passing by and saw I needed assistance.  My boat began listing to port and I was able to get onto the SeaTow vessel.  After getting on board the SeaTow vessel, my boat capsized to port and remained mostly submerged with just the bow above the surface.
  
  Investigation revealed:
  
  Operator #1 was traveling south in the intra-coastal waterway in the area of submerged ICW marker number 401.  The vessel was cruising approximately between 15 - 20 knots.  The vessel struck the broken submerged metal ICW day marker number 401.  The day marker was approximately one foot beneath the surface of the water and not marked.  The vessel struck the submerged day marker with the keel of the vessel and continued aft down the keel until it struck the out drive.  The collision with the out drive caused the out drive to become completely detached from the hull of the vessel.  The result was a compromised hull where water was now able to enter the hull. No injuries were reported as a result of the vessel striking the submerged object.  
  
  While on scene, I observed vessel #1 mostly submerged below the water with only the starboard area of the bow above water.  I was advised vessel #1 had struck a submerged object as well as the USCG vessel that was previously on scene.  I utilized the GPS mounted side scan sonar that my vessel was equipped with.  While displaying a split screen combo that included the navigational chart and the side scan sonar image, I was able to locate the submerged object that the two vessels had struck.  The submerged object was identified as the vertical ICW marker number 401 that was displayed on the chart but not visually present above the surface of the water.  The submerged marker was approximately 50 feet from the location of vessel #1.  I was advised by the Avalon Police Boat on scene that there used to be some type of buoy temporarily in place marking the submerged day marker however it was missing at this time.
  
  Vessel #1 exhibited a large gouge down the keel of the vessel and the out drive being completely ripped from the hull of the vessel.  Vessel #1 also exhibited damage from sinking.  Information for this report was complied by the operator's statement, damage observed to the vessel and information gathered on scene.
  