You're just dying to have a blender onboard, but don't have a generator to power it, and we all know the 12v models don't work worth a darn. I have FOUND the answer: Turn your cordless drill into a blender! 
The more powerful your drill, the better it will work...ideally at least 1,000 rpm model (so, now you have the perfect excuse to upgrade your cordless drill). Drop by the paint department at Home Depot and pick up a paint mixer bit for it (they come in several sizes--from "paint can" to "5 gallon bucket")--for about $2..larger sizes are a little more. As for the "jar," any container that has lid you can drill a hole in to stick the shaft of the mixing bit through will work. Stick the mixer in the container (the mixing blades should be at the bottom, like a blender), add ice and drink ingredients, slide the lid on over the bit shaft. attach the drill and squeeze the trigger. Blend till smooth. Crushed ice will work better than ice cubes. The drill should be one that uses rechargeable batteries....buy several sets of spare batteries, so when one set runs down you can just pop in another set. And--I also recommend some practice at home to get the hang of this before trying it aboard! I got this idea when I saw a website from somebody who's developed a kit for $39 (You can see that at http://www.boatblender.com/ )...and THEN remembered someone telling me about a dockmate using his cordless drill to make mashed potatoes for Thanksgiving dinner on the dock...and thought, "why spend $39, when all you NEED is a $2 paint mixer bit and a round Rubbermaid juice jug? Try it...It works!!
The more powerful your drill, the better it will work...ideally at least 1,000 rpm model (so, now you have the perfect excuse to upgrade your cordless drill). Drop by the paint department at Home Depot and pick up a paint mixer bit for it (they come in several sizes--from "paint can" to "5 gallon bucket")--for about $2..larger sizes are a little more. As for the "jar," any container that has lid you can drill a hole in to stick the shaft of the mixing bit through will work. Stick the mixer in the container (the mixing blades should be at the bottom, like a blender), add ice and drink ingredients, slide the lid on over the bit shaft. attach the drill and squeeze the trigger. Blend till smooth. Crushed ice will work better than ice cubes. The drill should be one that uses rechargeable batteries....buy several sets of spare batteries, so when one set runs down you can just pop in another set. And--I also recommend some practice at home to get the hang of this before trying it aboard! I got this idea when I saw a website from somebody who's developed a kit for $39 (You can see that at http://www.boatblender.com/ )...and THEN remembered someone telling me about a dockmate using his cordless drill to make mashed potatoes for Thanksgiving dinner on the dock...and thought, "why spend $39, when all you NEED is a $2 paint mixer bit and a round Rubbermaid juice jug? Try it...It works!! 