It's spelled Silicone. (Part of the value of an
internet forum is being able to search it for questions that have already been answered. That's a lot harder to do when posts are full of spelling errors, particularly in the subject!!!)
Whether its "good for boats" depends on what you are intending to do with it. Whether a hose is being exposed to solvents,
oil, heat, flexing, whether it's installed above or below the waterline (will the
boat sink if it fails?) all go into the decision as to whether a particular hose is appropriate or not.
As for the hose, just knowing it's material isn't the whole story. Is this hose reinforced or not? With what? What does the manufacturer state it's working temperature range is? What's the wall thickness? Whats the pressure rating? Whats the vacuum rating?
You don't want the hose getting super soft because you are getting it hotter than the manufacturer intended. You don't want it to collapse because it can't handle vacuum. You don't want it to burst because it can't handle pressure. You don't want it to dissolve because you are putting chemicals through it it wasn't designed to handle.
But yes, there are
coolant - capable hoses being
sold that are made mainly of silicone.