One single marine battery charger may not work for every individual situation. Many types of chargers are on the market; each one different from the other in some way. The variety often confuses people and they mistakenly buy the wrong charger for their marine batteries.
I am sure that you have heard of boat shoes, it is a broad term used to describe a huge segment of the footwear industry. Most of us are familiar with those made by the Sperry Company that have made the word "topsiders" a household name. Native Americans can probably be credited with the original design that shoe makers have adopted and made into the boat shoes of today.