US Coast Guard District 8 published an MSIB on the IHNC lock closure and the impacts on ITVs with COIs issued for Rivers Routes.
Effective 08/31/2020 and continuing for approximately for 60 days the IHNC will be closed to all marine traffic due to dewatering operations, repairs, and maintenance. For the duration of the closure an alternate route has been established utilizing the Mississippi River (Alternate Route). The Alternate Route will be completed by transiting via the Baptiste Collette Bayou Channel, through Breton and Chandeleur Sounds, as well as to and from the eastern reaches of the GIWW near its intersection with the Gulfport Ship Channel.
The USCG has made arrangements for vessels subject to 46 CFR Subchapter M that normally operate on Rivers routes (less than 3 nautical miles from shore) as indicated in the MSIB.