RedactedNarrative: CPO 2 and I were on boat patrol and locking through at the Chicago River/ Lake Michigan. Vessel one(rental boat captained by USCG captain) reversed into Vessel two, a privately owned boat(captained by a USCG captian). The collision caused damage to the V1 owned by Pinnecle yachts to the swim platform. Damage sustained by V2 was a cracked hull without leakage and an accessory light was no longer functioning.
  
  No injuries sustained. Only property damage was sustained.