Open 5.70 Sailboat Review, Specs, and Listings

Design and Construction

The Open 5.70’s molded hull uses a foam core inside fiberglass-reinforced polyester built out of glass fiber reinforced polyester, and the deck is a 15mm PVC foam-core sandwich. A large fixed longitudinal structure connects deck to hull, giving the 450 kg hull its rigidity. Ballast totals 180 kg and is split between a 30 kg glass-injected fin and a 150 kg lead bulb, while the T-keel itself lifts: fully deployed it draws 5 feet 9 inches, but can be blocked at 1.40 m for shallower waters, giving a 4 foot 6 inch shallow-water mode. Twin retractable rudders complete the helm. The waterline stays narrow to cut wetted surface even as the hull carries the longest possible floating waterline of 5.70 meters, a deliberate trade for speed over interior volume.

Rig and Handling

The boat carries a fractional sloop rig with a pivoting wingmast held by a forestay and two aft shrouds, using the same rotating mast and boom as the Hobie Tiger catamaran. Rig tension is set by a bolt jack under the mast, and mast stability is aided by a diamond arrangement pressing on two small spreaders that rotate with the mast. Sail area runs 18 square meters in the main and 8 in the genoa, with a 32-square-meter asymmetric spinnaker flown from a telescopic boomsprit; the kite hoists through the gap between shroud and mast, and one person can manage both hoist and takedown alone. A stern-mounted mainsheet and traveler, typical of modern cats, takes advantage of the extreme beam to give a long traveler span. Test sailors found that the combination of leech tension and traveler throw is the key to making the 5.70 go uphill, and with two aboard they easily hit boatspeeds in the mid-teens in a 12- to 14-knot breeze. Setup runs about 30 minutes to rig, tighten, and launch, and the boat can be ramp or hoist launched.

Accommodations and Cockpit

There is no enclosed cabin; the Open 5.70 is a large open cockpit that gives ample space for handling and lets crews optimize weight placement. Testers describe the cockpit as wide open, and the beamy layout supports a class maximum crew weight of 573 pounds, with European fleets usually racing three and U.S. testers sailing two. The cockpit’s openness and the lifting keel make the boat as much a schools-and-clubs trainer as a regatta weapon.

Known Issues

The builder claimed unsinkability through the foam-core construction and sealed volumes according to U.S. importer Jerome Sammarcelli, and the manufacturer describes the design as unsinkable and hardly capsizable.

Refits and Ownership

Ownership centers on transportability and simplicity: the 2.55-meter beam is at the maximum road size, so the boat trails easily, and the 30-minute rig-up keeps it low-friction for clubs and private owners alike. The rotating wingmast and catamaran-style traveler are proven hardware shared with the Hobie Tiger, which simplifies spares.

The Verdict

The Open 5.70 is a purpose-built sportboat that trades creature comfort for outright fun and accessibility. It rewards sailors who want catamaran-style speed in a monohull they can trailer, ramp-launch, and hand to junior programs without fear. The lifting keel and twin rudders extend its range from shallow estuaries to open regattas, and the unsinkable foam-core hull backs up its schools-and-clubs brief.

Pros