[Sirrotica]

A compression fitting has a ferule that slides over the tubing and is crimped by a internally tapered nut and are definitely not legal for a brake system. A double flared fitting is legal for a brake system and is what OE fittings and lines use at the connection points.

Just a FYI, stainless is probably what should be used in a salt environment for brake line, however cost is usually the reason it isn't. Don't ever use copper tubing, while it will handle a salt environment better, it work hardens from vibration as well as not having an acceptable working pressure due to being softer than steel or stainless alloys.