If you ever encounter a group that wants to plan a "marine event," then you should refer them to this regulation that spells out the procedure.

33 CFR § 100.15 - Submission of application

Once they determine that they need to submit an application, an online version of the form can be found here:

Application For Marine Event Permit

And a paper copy of the form can be found here:

Coast Guard Form CG-4423

This form needs to be submitted to the Coast Guard District Commander no later than 135 days prior to the event.  That's a long lead time, so plan accordingly.