It's a myth that all dogs know how to swim. They have to learn to swim. :) Because of this, all dogs that are going to be near water must wear life jackets. Even dogs who are fantastic swimmers need the life jackets. If something happened and they were forced to swim for a length of time, just like a human, they can get tired and drown. This is very common even among great dog swimmers.
There are plenty of great life jackets available for purchase on line or in pet super stores.
As for a dog who doesn't like water, IMO, don't force them to swim. If they don't like it, so what? Not all dogs like water, just like not all people like water. Love them for who they are.
As for it being a "breed" thing, this isn't always true either. I know dogs in my breed (shelties) who love water, although the breed is known for not being a water loving breed. My personal shelties hate water. That's OK. I let them be themselves. :)