Design and Construction
The 400's structure follows a modern vacuum-infused polyester build, with solid laminate below the waterline and balsa core above, including in the decks. The builder applies vinylester resin to the hulls as an osmotic barrier. Compared with most 40-foot catamarans, the hull beam and freeboard are impressive, and the platform itself is very beamy at 7.25 meters. A carefully shaped surface under the nacelle sits 50 to 70 centimeters above the sea, a detail Multihulls World noted as deliberately engineered rather than incidental. The boat carries 75 inches of freeboard to the deck, a high superstructure, and low-aspect keels — a combination the design team clearly built around comfort and payload rather than closewinded agility.
Rig and Handling
The 400 carries a tall rig, taller than that of a Nautitech 44, with a standard full-battened mainsail of 603 square feet and an optional square-headed main stretching to 651 square feet. Lagoon rigged an inventive line system that automatically tensions the upper luff to the spar as the square-headed main rises. A short bowsprit carries a screecher, and all halyards and sail-control lines lead aft to a dedicated steering station above and to port, enclosable with zippered curtains in foul weather. Under sail, writing in Cruising World, test sailors found her driven at 4.5 to 5.2 knots in 6 to 7 knots of wind when reaching with a screecher set on the bowsprit. Cruising World's testers noted she performs best when sailed fully powered and eased a few degrees off the wind. Twin diesels set nearly 24 feet apart let her back up and twirl around almost magically, and under power the 40-horsepower Yanmar option loped along at 7 knots at 2,200 rpm. Still, the significant windage with beam wind while maneuvering in harbor is a real handling caveat, and the lack of a step onto the cabin top drew tester concern for crew needing to reach the main pouch.
Accommodations
Inside, the 400 aims to deliver luxurious living in a space comparable to that of a 60-foot monohull. Whitewash-finished panels and beech joinery, large ports, and wide soles in the hulls keep the saloon bright. The vertical ports wrapping around the bridgedeck saloon shade the interior and lift headroom, the signature Lagoon look. Aft double berths sit lower in the hulls with side cutouts for easy access, multilayer foam mattresses on slats for ventilation, and halogen fixtures throughout for excellent lighting. Forward V-berths have sliding fillers revealing large storage lockers. A three-cabin layout yields an enormous bedroom/office/bath with storage space for an optional washing machine. One large roof sweeps from cabin front aft over the cockpit, forming an exterior saloon. The galley includes a molded-in dish drainer, though the builder acknowledged that adding a second fridge or freezer would cut deeply into provision storage on early boats, with overhead cabinets planned for later units.
Known Issues
Cruising World's Boat of the Year judges found the latch locking open the sliding door and window between saloon and cockpit hard to operate. The same panel flagged that children might reach the saloon electrical panel, a risk felt preventable with a lock. The absence of a step to the cabin top remains a practical annoyance for sail handling at the mast.
Refits and Ownership
Owners shopping the 400 will find a CE certification rating of A:8 / B:14 / C:20 / D:20, speaking to offshore capability for a catamaran of this size. The standard 30-horsepower Yanmars or optional 40s, paired with the maneuverable twin-gearbox layout, make docking manageable despite the windage. Many models left the factory or were later fitted with electric winches, easing the tall rig's demands.
The Verdict
The Lagoon 400 is a volume-driven cruising catamaran that trades upwind finesse for livable space and easy powered maneuvering. Its construction and rig reflect a considered third-generation Lagoon approach, and the accommodations remain a strong draw for liveaboards and charter buyers alike.
Pros
- Beamy, high-volume interior rivaling a 60-foot monohull's living space
- Twin widely spaced diesels deliver exceptional close-quarters maneuverability
- Tall rig with optional square-headed main and automatic luff tensioning
- Solid-laminate underwater hull with balsa-cored decks and osmotic barrier
Cons
- Significant beam-wind windage complicates harbor maneuvering
- No step to cabin top hinders mast-access sail handling
- Hard-to-operate saloon sliding-door latch and accessible electrical panel noted by judges
- Low-aspect keels and freeboard discourage pinching up to windward
