I can certainly try based on some previous SNE threads and some blog posts from hams who have volunteered in the past.
On the Amateur Radio side of thing you'll hear Safety Launches which will have at least one Lifeguard in them for any on the water medical incidents (see
https://www.hocr.org/lifeguard/). You'll also hear first aid tents and walking teams for medical incidents on land. Today all I really heard from the Safety Launches were requests for bio breaks and that unattended bag you mentioned earlier. For the walking team someone skinned their hand. I expect more traffic on the repeater tomorrow. Still haven't decided if I'm keeping it on the feed but I probably will as hams are primary for a lot of medical comms.
On the MSP side of things there is at least one Marine unit on the Charles. I heard it on Events 3 and also saw it in the background of the livestream by the finish line. Based on SNE threads there have been at least two Events TGs in the past, one for Marine, one for Land. As to EMS boats I have no idea but I know that Cambridge FD has some boats though I think most of this is in the realm of the Safety Launches.
DCR is involved in some capacity since the course is on the Charles River Reservation. I heard a couple of things about helping out stuck boaters (a shell hit a bridge) on DCR Field Ops but that's also a statewide TG so will also have non HOCR traffic.
In terms of behind the scenes channels that would be the good old DC Rentals/All Comm trunked DMR system. This is not included in my feed as it may not fall under the TOS being "private". Info on that can be found here:
All-Comm Technologies Trunk - Scan New England Wiki
Courtesy of
this thread the following TGs have been identified as active:
231 - Emergency Services
232 - Technology
242 - Operations or River Control
243 - Computer Timing/ Cambridge Boat Club
Since
the course is entirely in Cambridge and Boston I doubt Watertown or Newton will be involved. I'm not sure how much BEMS/BPD/BFD or Cambridge PD/FD/EMS will be involved as this is my first year monitoring the event. They're all included in the scan rotation just in case but I feel like most public safety traffic will probably go through UCC/CP/LECC/etc on one of the MSP Events TGs.
*edit* I hope there aren't any other events tomorrow using the MSP Events TGs so there isn't any confusion for those listening! I am broadcasting Alpha tags so hopefully if there are multiple Event TGs in use someone can post the ones that are being used for the HOCR. Downside of monitoring all eight of them but better to hear too much than not hear something.
