There are several problems:
There's nobody who will _receive_ an HF DSC call on the ham bands -- it doesn't exist as a "standard protocol", and there are no standard "emergency frequencies" on the ham bands. ? So first thing out of the gate, you'll have to "open up" the IC-7000 for "all frequency" transmit. ? And you'd have to feed the GPS into a computer, and have the computer format the message correctly, and control the radio to send it out. ?As far as I know, the software to do that hasn't been written, yet.
. . . This is _not_ a good emergency tactic!
Too many things have to be "just right" for it to work.
My suggestions, for what they're worth:
If you;re doing coastal sailing, use a VHF radio (connected to the GPS) to send the DSC message. ?It'll have a short range, but the US Coast Guard and Canadian Coast Guard _do_ monitor the appropriate channel
If you're doing offshore sailing, get a proper 416 MHz EPIRB with built-in GPS. ?That will get you connected to an international satellite-based search-and-rescue network when you press the big red button. ?The EPIRB has its own battery, and will transmit for days, floating in the water. ?You can't say that about an IC-M802.
There are some times when there's no good alternative to "spend the money!". ?This is one of them.
An IC-M802 is an expensive piece of gear. ?I used an IC-706 (modified for all-frequency transmit) for several years of cruising along the Pacific Coast, and it worked fine. ?But you _do_ have to know what you're doing. ? An IC-M802 is closer to an "appliance" than any ham rig.
. ? ? ? ? ?Charles / VA7CPC / "Right Galah", Morgan 36 Out Island sloop
PS -- the "Spot" satellite beacon might be worth looking at. ?Some skiers (in BC, I think) were just rescued using it. ?I don't know if it works offshore; satellite coverage might be limited to land and near-shore.