Open sailboats: a one-design class, not a builder
A "make: Open" listing does not point to a boatbuilding company called Open. It names a one-design sportboat class -- the Open 5.70 and its smaller sibling, the Open 5.00 -- drawn by the French naval-architecture office Groupe Finot and turned into hulls by more than one yard. Sailing World credits the design the same way Phileas Boats' own material does, and Latitude 38 documents boats built on both sides of the Atlantic to that one design. Reading an Open listing means separating three questions the make field alone can't answer: who designed it, who actually built the specific hull, and which of the two models it is.
The design: Groupe Finot's cost-conscious sportboat
The Open 5.70 traces to Groupe Finot -- rendered by Phileas Boats' own material as "Groupe Finot Conq," and credited elsewhere to French naval architect JM Finot individually. The brief was explicit: the office drew on its experience with earlier modern boats, especially the Open 7.50, aiming for a boat that was both physically and financially accessible. That accessibility shows up in specific choices rather than marketing language. Sailing World singles out the twin-rudder layout -- two smaller rudders angled outward from the hull -- as Groupe Finot getting a detail right. The same cost logic extended to the rig: the 5.70 uses the same rotating mast and boom as the Hobie Tiger catamaran, a high-volume design chosen specifically to keep costs down and replacement parts easy to find.
Who builds an Open
Phileas Boats, based in Rochefort, France, is the class's primary and originating builder -- the only one with first-party manufacturer material in the record, describing itself plainly as a French manufacturer of dinghies and sport keelboats. Latitude 38 documents a second builder: boats were also built by Columbia Yachts in the USA. The publication doesn't describe how that arrangement worked -- licence, subcontract, or something else -- so a listing naming "Open" as the make doesn't by itself say which of the two yards built it; that is a question for the boat's own paperwork, not the class name.
Construction through the range
Both models share a fiberglass-based build, arriving within a tight window either side of the turn of the millennium -- the 5.00 in 2000, the 5.70 in 2002. The 5.70's hull is a foam-cored, molded structure in fiberglass-reinforced polyester, stiffened by a large fixed longitudinal structure connecting deck and hull; its deck is a 15mm PVC foam-core sandwich, and its ballast is a glass-injected fin carrying a 150-kilogram lead bulb. The smaller 5.00 instead uses a polyester hull and deck with an internal stiffening structure rather than a cored sandwich, a single lifting rudder, and a deep keel -- 95 kilograms, described by the builder as sized for safety -- that rotates to reduce draft and, fully retracted, lets the boat come ashore easily.
The 5.70 and the 5.00
The 5.70 came first and carries the class's public identity: Sailing World named it its 2007 One-Design of the Year, with judges calling it fast, fun and stable and an instant hit in testing, and the first boats reached the United States that same year. The 5.00 followed as, in the builder's own words, "the latest boat born from Phileas" -- pitched as a more accessible family boat for three rather than a smaller racer. The relationship between the two stayed close after launch: the Open 570 owners' association also looks after the 5.00, describing it as the "little brother" model.
Who an Open sailboat is for
Phileas Boats' own product material places the 5.70 in the tradition of one-design keel dayboats like the Star, the Aile and the Soling -- the maker's own framing, not a neutral judgment, but a reasonable description of the boat's intended company. The class was built with a specific range of sailors in mind: sailing schools, rental fleets and clubs, young sailors under reduced supervision, and, in regattas, adults who have passed the age for dinghy acrobatics. It also runs under its own class rules -- Sailing World reports a maximum class weight of 573 pounds -- a sign that owning an Open means joining a defined one-design class, not simply buying a hull. Phileas Boats has also described a fleet of 5.70s and 5.00s sailing on the west coast of the USA.