I considered a Doomboat as one of the more economical means of giving yourself some security and mobility when TSHTF. If I was going that route, I'd go with a 30-45' sailboat equipped with PV panels as well as wind powered generators to keep the batteries charged. Not too big a boat because it takes too many people to sail, no smaller than that because you just couldn't really keep enough Preps aboard. Also, larger and fancier boats would be more attractive to Pirates or plain old Burglary at the dock.
The upside of the Doomboat especially in your big cities like NYC or LA that have Ocean Access means even in a real quick SHTF scenario, you still could theoretically Bug Out in time. Also if you have enough experience in deep water, in theory you pretty much could head anywhere in the world you felt might give you a better survival possibility. When other people can't get on a plane no matter how much money they have in the bank, you still could raise the Mainsail, haul up the Anchor and head for that Secluded Cove on Gilligan's Island. Bring Ginger and Mary Ann along for the ride, Leave Mr and Mrs Howell behind

In addition to the romantic upsides to the Doomboat scenario, you have the realistic problems with it as well. First off, if its bad enough to need to sail away in your doomboat, I doubt anyplace where there is a real Marina and docks to tie up to would be very safe. If you left your boat for any length of time, it probably would be broken into and food preps and electronic gear stolen. I don't think a small yacht like this is in too much danger of piracy at sea, but its vulnerability to theft once near shore is tremendous.
So, what you would be looking at in a Bug Out with such a Doomboat would be heading to some low populated island where you might want to try to live off the land and fishing. I wouldn't try it on a Desert Island, but you might do OK if you are good at making friends with some local fishermen in Nuku Alofa maybe. While your chances might not be great, they would I think be better than hanging out in NYC waiting for the Food Bank to get a Delivery.
In terms of finances, it would be my bet that right now you could buy yourself a good seaworthy boat at auction for $20-$30K, and preps for a year to stock on board for another $10K. No other Doom Protection Scheme can be had as cheap and provide Shelter and Mobility on a World Wide level for so little cash. However, the dangers from theft and piracy are certainly real in any scenario where using such a boat is truly necessary.
Reverse Engineer