I know I could do it on 6K a year, whether you can do it on 16K is up to you.
The simpler the boat is, the simpler it is to fix. My last boat I lived aboard 3 years and never spent dollar one in maintenance, I did do some bartering and used a lot of hands-on elbow grease. I also made a conscious decision to do without an engine, which involved a little more thinking, patience and sailcraft...but I wasn't sorry to wake up each morning without the smell of gasoline in my nostrils. In one area I found an ideal anchorage where I had to maneuver down a short canal to get into open water, and I built and employed a sweep to do this! Which attracted a lot of attention and catcalls but it works. For some people finding the simpler/cheaper solution is an adventure in itself, for other people it's pure torture to be without conveniences and appliances. Know your limitations.
If people draw up a budget that shows where their dollars are going, they're often amazed how much money goes into the "Entertainment" category. Buying cocktails for you and your mate in St. Thomas can cost you 2 weeks in food bills for a frugal shopper, you can go to the movies with your honey, or buy a BOX full of old movies at a garage sale you can watch for years, at the same price. I found when I was cruising I would start to miss red meat and salads, I would dehydrate beef and venison (I'm a hunter) when I was at my homeport working and "restocking the kitty" and while cruising soak the dry meat to reconstitute it a little before cooking in a casserole or pasta sauce to get a taste of something "meaty". (There's nothing like a big juicy steak, though...SIGH...maybe if you're sailing up Canada way you'll find caribou browsing on the beach...LOL!) I've been in foreign ports where a head of lettuce cost $7 (NOT kidding)...the only solution I've found for this is bean/alfalfa sprouts. You can sprout beans and alfalfa by putting the seeds into a loosely lidded jar with a little water, and turning and shaking it regularly, the seeds expand until the jar is full of sprouts, then expose to sunlight to "green them up" just before use...vinegar and oil and and you have a very acceptable and healthy salad, very crunchy and green. Buy food in bulk, look for the "dented can" discount stores that are a "hidden secret" in a lot of large towns. Restaurants use these giant 10 gallon containers for shortening, pickles, etc. with these wonderful sealing lids that are IMPERVIOUS to anything except a nuclear strike, when they're empty they just throw them away! Scrounge a few of these and you have storage containers that will keep food, clothes, electronics, etc. bug and humidity proof for years! AND of course, there is a lot of SEAFOOD to be had out there! Buy all the spices, peppers, condiments etc. to keep variety in a seafood-prominent diet. I had a driftwood-fueled hibachi attached to my transom for cooking, it was a pain starting a fire first thing in the AM to put a percolator on, but hey, now I have the skill of starting a fire anytime, anywhere under ALMOST any conditions with one match...and no necessity for finding propane/butane/whatever in a strange port (I kept a primus on board for "rainy day" emergencies...I can live without food longer than I can live without coffee). Every time I went on shore, I would come back with driftwood I'd scavenged in hand...the bench lockers in the cockpit were stuffed full with it...! And the helpful thing about having an actual FIRE with coals, is you can employ dutch oven cooking, bake your own bread, cakes, pie, plus "crock pot" type cooking...and, of course, the salt in the driftwood makes a multi-color display that's very beautiful at dusk during the cocktail hour...
You get the gist, and if you find you enjoy these kind of frugal pursuits, you may find you've saved enough money to use strategically on the conveniences you miss most, just make sure their maintenance costs don't sabotage your original purpose. Hit garage sales for computer games, old movies. Libraries often have book sales to offload excess donations, I've often gone to library sales where they unloaded paperbacks for a few dollars for a BAG of books...pawn shops for music CD's, stereo equipment, bicycles. Upgrade your wind/solar systems to POWER your goodies on board.
One modern convenience I've found to be a "necessary expense" is wireless internet. It costs under $100 per month, it works in almost any US location, and the amount of communication and entertainment it provides justifies the cost. Plus, in my case I find it necessary for a small internet business I have that keeps me in the black...! (A great idea for another thread, how cruisers can make money on the Net so they can keep on cruisin')
That's all I can think of offhand...I've often thought there should be a website for "frugal cruisers" but I haven't run across one as yet!