Well, in terms of having a plan, most of the passages I have participated in or have followed, have a sizeable following on land. We message our shore crew with our position and they come back with the positions of competitors and a discussion of weather/tactics. In one case last year, in the North Atlantic, there was a massive storm, boats were retiring left and right (I was on shore), our team was leading the
race and then their
keel came loose. As soon as we got the message (with the coordinates), we raised pretty much everyone involved and things started rolling. There were "comfort phone calls" to the crew but the actual direction of the rescue happened over InReach and then over VHF.
It is so much easier for someone on land to organize the rescue and handle the
communications instead of the crew that was busy keeping the boat afloat. I would imagine that most people crossing oceans have some following on land, friends,
family,
kids, etc. The only issue I see is that people on land start getting worried if there is an interruption of regular communications but this is part of life.
If you want to be self sufficient, then HF DSC makes more sense but it is so complicated, the radios draw 1-2A in standby, it is a mess for recreational sailors. Why can't you have a simple app on the phone, connected to a
low power, scanning SW receiver, drawing 0.2-0.3A and capable of receiving HF DSC? DSC could also be incredibly useful to call each other on HF if it was faster/easier to compose a non distress call.
We have tried using selcall (we just pick random codes) and an Android app to alert each other when we want to talk but it is always easier to go via Inreach. So, for me, HF is most useful for
email and GRIB downloads. Voice also but I lose patience with the nets, there is always something to do on the boat at the net time.
Sometimes, it is fun to do PSK31 to random hams, great folks to talk to. I have experimented with ALE but it takes too much
power (ALE is a digital protocol, where the PC controls the radio, transmits occasionally on a list of frequencies and pre-selects the best frequency for you. So, all you need to do is just pickup the mike and talk). Yet, most of the time you know what the best frequency is, so why leave the radio constantly scanning and working out the tuner to tell you something that you know?
My view is that marine HF works great in
commercial settings, large ships,
ample power budgets, etc. Recreational sailors adapted it for voice and
email and you have fairly robust apps for that. Hams came up with digital fun modes which could be useful as a hobby. Then DSC came along but it was never made user friendly, so it never picked up.