Ceramics are a good choice for the average home cook. That said, it really depends on what condition the knives are in, what the knife is made of, and what type of knife it is. If the blade is chipped, slightly bent, or even a very hard metal like high carbon stainless steel knives (Wusthof, Henkel, Global, etc) a ceramic sharpener won't
do the job.
are typically designed for delicate knives, such as japanese style sushi knives, as they usually don't end up with chips, bends, and are commonly made from carbon steel, much softer than stainless steel or a combination of the two.
Professional chefs commonly used whats called a Tri stone
, 3 different levels of grit, coarse, medium, and fine that uses mineral oil to lubricate the stone and knife. A bit bulky for a boat
There are the electric style
which you mentioned in your original post, which make sharpening easier and more precise, when used correctly, however they can really take of allot of steel and probably not a good choice for a boat.
There are several other designs and innovation's, however with my 20+ years as a professional chef, most of my knives I have had for that long, using a diamond stone and tri stone, is for me the way to go.
FYI...The only way to truly sharpen a serrated knife is to have it professionally ground.