Design Philosophy and Construction
The 400 was conceived around a single organizing principle: deliver living volume equivalent to a much larger monohull on a hull length just shy of forty feet. A beam of 7.25 meters — generous even against contemporaries in its class — gives the bridgedeck saloon and twin hulls a footprint that has no real equivalent in single-hull sailing. VPLP kept the underbody honest: 100% sailing hulls rather than the fuller, volume-optimized sections of the preceding Lagoon 420, and a tall rig that stands taller than some competing 44-footers. The hull construction uses solid laminate below the waterline and balsa core above, with polyester infusion throughout and a vinylester osmotic barrier on the topsides — workmanlike choices for production volume and longevity.
The freeboard is significant, and the superstructure rises high above the water. Both contribute to windage that requires caution in beam-on harbor maneuvering, but the twin diesels positioned far apart give the boat extraordinary low-speed control under power — backing, twirling, and docking with a precision no single-engine boat can match.
Rig and Sailing Behavior
The fractional sloop rig is straightforward, and Lagoon made a smart call with the mainsail. An optional square-headed mainsail boosting area to 651 square feet is the configuration most worth seeking out, while the standard full-battened main measures 603 square feet. Handling the square-head was simplified by an inventive tensioning line system that automatically tightens the upper luff as the sail rises — and releases it on the drop so the top collapses cleanly into its bag without the usual batten wrestling.
The small jib is genuinely easy to manage, and a roll-up screecher on a short bowsprit rounds out a simple sail plan that is straightforward to power up or ease without drama. The package produces a sail area-to-displacement ratio of 18.18 — solidly in the reasonably good performance band for a cruising catamaran of this displacement. What the numbers don't fully capture is the character: the 400 moves well in light air, having reached at 4.5 to 5.2 knots in just 6 to 7 knots of wind during testing, and tracts well under power at a hull-loping 7 knots on 40-horsepower optional Yanmars at only 2,200 rpm.
The high freeboard and low-aspect twin keels do impose one genuine constraint: the boat should not be pinched. It performs best when sailed fully powered and eased a few degrees from a closehauled heading, which is exactly how a liveaboard cruiser ought to be handled anyway.
Accommodations and Interior
The interior is the boat's strongest selling point, and Lagoon designed it with rare attention to the lived experience. The hull soles are wide, the joinery uses whitewash-finished panels and beech timber, and large ports admit generous natural light. Engines are mounted well aft, which pushes the aft double berths lower in the hulls; cutouts in the hull sides let crew slide into bunks laterally, and multilayer foam mattresses sit on ventilating slats to prevent mildew buildup beneath.
Four layout options were offered. The three-cabin variant delivers an enormous owner's bedroom, office, and ensuite head with space enough for an optional washing machine. V-berth fillers forward can be slid out to reveal large storage lockers. The bridgedeck saloon features Lagoon's signature vertical rather than sloped ports — a detail that simultaneously shades the interior and buys headroom over the settee and navigation station. The galley is properly equipped, including a molded-in dish drainer. Water capacity stands at 299 liters and fuel at 401 liters, adequate for offshore passages.
Deck Layout and Safety Details
The cockpit and helm arrangement prioritizes ease of operation. One large smooth-sweeping roof runs from the cabin front aft over the entire cockpit, creating a shaded exterior saloon. A dedicated steering and control station sits above and to port, enclosed by zippered weather curtains when conditions deteriorate, and all halyards and control lines route to the helm station so the boat can be sailed short-handed from a single position.
Lifelines are 35 inches high and tripled across the stern — a meaningful safety measure. Teak toerails along the sheer provide grip in an emergency, and flush-set deck hatches eliminate the trip hazards that plague boats of this era. At the bow, a dedicated chain channel directs the anchor rode cleanly from windlass to roller. Aft, the transoms are cut away inboard and fitted with sturdy handholds to receive the dinghy and facilitate passenger transfers.
Known Issues and Owner Considerations
Cruising World's Boat of the Year evaluation flagged two practical concerns that prospective buyers should audit on any example. The latch mechanism locking the sliding saloon-to-cockpit door open proved difficult to operate — a small but real injury risk under way if the door slams unexpectedly. Additionally, the electrical panel in the saloon was accessible to children without a lock, a safety gap the skipper must address through either a retrofit lock or deliberate monitoring.
The significant windage from the high superstructure is not a defect but a characteristic to manage: in crosswinds, harbor maneuvering demands early planning and confident use of both throttles. The stern lifelines, while a safety positive, must be opened to access the engine compartments, which is inconvenient and potentially hazardous if done in a seaway. And though the helm station is well served by control lines, gaining access to the cabin top for sail-pouch work at the mast lacks a dedicated step, an omission owners typically address with an aftermarket solution.
The Verdict
The Lagoon 400 is a thoroughly professional piece of work — not a fast boat, not a spartan ocean passage-maker, but a highly capable liveaboard cruising catamaran with a well-considered rig, a genuinely livable interior across multiple layout configurations, and the production pedigree of a builder who had constructed thousands of catamarans before this hull hit the water. VPLP's input ensures the sailing behavior is honest and the underbody is properly shaped; Lagoon's production know-how is evident in the quality of the small details throughout the deck and interior. It is a boat that rewards sailors who sail it the way it was meant to be sailed: fully powered, eased off the wind, and unhurried.
Pros
- VPLP-designed sailing hulls with a tall rig and square-head mainsail option give genuine light-air performance for a cruising catamaran in this displacement class
- Exceptional interior volume across four layout options, including a full owner's suite with washing-machine capacity
- Twin diesels placed far apart provide remarkable low-speed maneuverability under power
- Thoughtful deck ergonomics: all control lines at the helm, high tripled stern lifelines, flush deck hatches, bow chain guide
- Solid laminate below waterline with vinylester osmotic barrier — a sensible construction choice for longevity
Cons
- High freeboard and superstructure create substantial beam windage, demanding respect in harbor crosswinds
- Must not be pinched on the wind; does not reward aggressive closehauled pointing
- Saloon door latch and electrical panel access were safety concerns flagged at launch and should be inspected on any example
- Stern lifelines must be opened to reach engine compartments — awkward at sea
- No dedicated step to the cabin top makes mast-base work unnecessarily difficult without an aftermarket addition
