Design and Construction
The Lagoon 51 measures 15.35 meters overall, with a beam of 8.10 meters and a documented empty displacement of just under 20 tonnes. Its CE certification covers categories A through D, with capacities of up to 14 or 30 people depending on class.
Lagoon infuses the 51’s balsa-cored composite hulls and decks, keeping weight down while preserving panel stiffness. With this model, the builder also began using bio-sourced resin for nonstructural small parts while experimenting with natural fibers such as hemp and linen.
Inside, Lagoon uses Forest Stewardship Council-approved Alpi wood throughout. The test boat introduced a lighter “sand oak” tone than earlier Lagoons; upholstery is made from fully recycled materials. The Bimini over the flybridge is injection-molded rather than fabric.
At the stern, the platforms extend beyond the hull sides. This enlarges the bathing areas and helps dampen pitching when sailing over waves. One structural consequence of the cockpit layout is that the 51 doesn’t have the Lagoon 55’s open-to-water terrace because the aft beam must rise above the cockpit sole.
The forward cockpit arrangement avoids adding weight well forward. It also won’t trap several tonnes of water if a crest breaks over the bows.
Rig and Handling
The Lagoon 51 marks a deliberate return to a forward mast position at the front of the coachroof. This saves weight and complexity while allowing sufficient sail area from a shorter mast, lowering the center of effort and reducing weight aloft.
The sail plan combines a large-roach or optional square-top mainsail with a 120 percent overlapping headsail. The main is cut for a little more power, and an aluminum sprit carries a reaching sail. The trade-off is that a self-tacking headsail is no longer feasible. Lagoon also shifted the keels forward to reduce interference and improve steering efficiency.
Except for hoisting and dropping reaching and downwind sails, all sail handling takes place at the flybridge. Three Harken electric winches sit within reach of the wheel, while a side-wind winch handles the traveler. A window in the overhead Bimini gives the helmsman a clear view of the square-top main. The roller-furler boom was developed with Wichard and Incidence Sails.
Testers found that the 51 isn’t close-winded. Its best progress to windward came at a true wind angle just under 55 degrees, producing 5.5 knots in 7 to 8 knots of breeze. Bearing away to 70 to 75 degrees raised speed to 6 to 6.5 knots. With a Code 0 set at 110 to 115 degrees, speed increased to 7 knots.
In stronger air of 10 to 14 knots, closehauled speeds were in the low 6s. The boat made nearly 7 knots on a broad reach, with a noted top speed just over 7.5 knots. Writing in Yachting World, test sailors found that the flybridge helm’s blind spot under the Code 0 reaches nearly 90 degrees when that sail is set.
Accommodations
In the four-stateroom owner’s version, the entire starboard hull is private. A queen berth sits aft beside one of three hull ports. Amidships, a desk and outboard seating provide a view, with a walk-in dressing room opposite. The owner’s head is forward, with his-and-hers basins and a fully enclosed toilet and shower.
The port hull contains three double guest cabins and two heads with separate stalls. The mid cabin is the smallest and has limited stowage. The forward cabin offers the best storage but shares its facilities. Lagoon also offers a charter-grade layout with six staterooms and four heads.
Social space is a major strength, with three distinct outdoor areas. The aft cockpit has a pair of three-seat settees and a four-person transom bench. The forward cockpit seats four or five and includes sunbeds and a coffee table over the windlass, though it has no direct access to the saloon. On the flybridge, a forward helm bench is followed by U-shaped seating around a cocktail table, with sun pads on either side of the mast.
The slightly raised saloon has eye-level windows, although the view is blocked on both aft quarters. A convertible table seats eight to ten. The navigation desk is forward to starboard, while the aft galley is divided around the sliding door. To port, L-shaped counters hold the stove, oven, sink, and dishwasher. Fridge and freezer drawers are to starboard, and high fiddles help secure items in rough water.
Equipment and Systems
A 12-volt electrical system forms the basis of the Lagoon 51’s energy plan. On production boats, more than 3,400 watts of custom solar panels line the perimeter of the flybridge and hard Bimini. The prototype carried around 3 kW and showed full self-sufficiency except when air-conditioning loads applied.
Efficient cooling units and LED lighting reduce demand. A 12-volt watermaker produces 100 liters per hour and can run from solar despite drawing 40 amps. It’s accessible beneath the port aft cabin floor.
Between the oversize transoms, the swim platform lowers for water access at anchor and rises to carry a tender underway. The test boat also had an optional hydraulic lifting platform.
Other environmentally focused features include UV water filters that reduce the use of single-use bottles, along with supplied green cleaning products. A washer/dryer can be installed in the starboard hull, and an additional 100-liter freezer can be fitted in the port hull.
Verdict
The Lagoon 51 is a thoughtfully evolved, owner-oriented catamaran. It trades the tight-winded, self-tacking convenience of earlier rigs for a forward-positioned, power-oriented sail plan and a genuinely palatial private hull. Its construction makes greater use of lighter, greener materials without abandoning infused-composite methods, and its social deck layout is among the most usable in its size class.
The limited windward ability and the Code 0 blind spot are real drawbacks, though they’re manageable with disciplined sailing angles and good crew communication.
Pros
- Largest Lagoon still intended for owner-operators
- Forward rig and shorter mast lower the center of effort, while the overlapping headsail adds upwind drive
- Entire starboard hull devoted to an owner’s suite with exceptional stowage and light
- Three separate outdoor social areas, plus a raised saloon with a convertible table
- Strong solar installation and a 12-volt watermaker support self-sufficiency at anchor
Cons
- Not close-winded; requires wide tacking angles to maintain speed
- Code 0 creates a blind spot of nearly 90 degrees from the flybridge
- Self-tacking headsail is no longer feasible
- Lacks the Lagoon 55’s open-to-water terrace because of the cockpit beam structure
- Forward cockpit has no direct access to the saloon
