Hi Ron,
You could an use inverter to run a coffee maker but you must be VERY mindful of the power ratings on the coffee maker and the inverter.
Some coffee makers require in excess of 1000w of power at 120v ac. WATTS = Volts x AMPS (at any voltage)
For example, the one on my kitchen counter is rated at 1100w. It brews coffee in about 10-15 min.
1000w at 12 volts would be 1000/12 = over 80 AMPS!!
so to power your typical 120v coffee maker you would need at LEAST a 1000w inverter. They are not at all 100% efficient either, a 1000w inverter that will indeed provide 1000w AC would probably draw close to 100A. (100a on a battery for 20min will probably kill it.....so you would probably need to run the engine unless you have some "herkin'" batteries!!)
12v coffee makers are not much better. To make them so they don't kill the battery before the coffee is brewed, you have to design them to not draw a lot of current, of course if you do that they take a LONG time to brew ............. Here's one: be sure to read the reviews too
http://www.cabelas.com/prod-1/0045876515272a.shtml.
What do you mean by "electric cooler"? If that means air conditioning, they'll draw lot of current also............ An electric fan doesn't draw much power and there's a lot of 12v models available....
I think if I wanted to make coffee on my boat I'd use a small propane model....(those have their own safety concerns though.......there's no free lunch!!)
Cheers,