Design and Construction
The 421's hull forms mark a clear departure from its predecessor. Vertical bows replace the older profile, and the transom skirts are much wider, while the bridgedeck itself is gullwing-shaped to part seas beneath the nacelle. Multihulls World noted the Bordeaux-based builder had slightly lowered the hull height and eliminated the rigid bimini that had perched very high above the 420's cockpit, replacing it with a new rigid bimini that extends the coachroof eliminated the high perch bimini. That structure carries the mainsheet track fixed to the bimini, leaving the cockpit clear, and the nacelle enjoys generous lighting from large vertical windows protected by the coachroof extension. Apart from the davits, there are no fittings aft of the coachroof, which keeps the aft deck uncluttered.
Rig and Handling
The sail plan grew from 97 to 103.4 square meters against the 420 boosted the sail plan, aided by a square-headed mainsail that improves performance in light weather. The mainsail itself measures 710 square feet with a 377-square-foot genoa and a 753-square-foot gennaker available. On the 421 the boom is the hoisted part of the hardtop, cut so it clears the skipper's fixed-bimini helm station without collision, and the fixed top even extends living space from saloon to cockpit while the boom could double as a sunbathing platform. Charter companies could specify a short mast deemed more reassuring for inexperienced crews, but the standard rig's hydro-dynamically efficient hulls give the 421 an edge the 420 lacked.
Accommodations
Buyers could choose three or four double cabins, and the saloon carries large vertical windows with large sunlight windows repeated in the cabins. Natural ventilation of all interior spaces comes from large and convenient opening hatches, while wide sidedecks and a wide aft deck ease movement outside. The cockpit is equipped with a changeable table so it can become either a dining area or a lounge, and because the mainsheet track is fixed to the bimini the cockpit can be 100% dedicated to relaxation rather than line handling.
Known Issues
The electric motors were finished as of the review period, and the 421's builder returned to diesel engines. The changes from the 420 were corrective rather than remedial.
Refits and Ownership
Ownership context is straightforward. The 421 pairs twin 40-horsepower diesels with 2 x 300 liters of fuel and 2 x 175 liters of water, and the rigid bimini structure offers a stable platform for later canvas or solar additions without altering the coachroof line. The short-mast charter option means used examples may vary in rig height, worth confirming against a given boat's sail plan before purchase.
The Verdict
The Lagoon 421 is a considered evolution of a flawed predecessor, trading experimental hybrid propulsion for dependable diesels and refining the deckhouse into a lower, cleaner profile with genuinely usable covered outdoor space. Its gullwing bridgedeck and vertical bows speak to a builder correcting course, and the clear cockpit earned by the bimini-mounted mainsheet is a real liveaboard advantage.
Pros
- Revised hulls and lowered freeboard over the 420 with more efficient hydrodynamics
- Mainsheet on the bimini frees the entire cockpit for relaxation
- Three- or four-cabin layouts with strong natural light and ventilation
- Return to diesel twin 40 hp drives after the 420's hybrid experiment
Cons
- Electric propulsion option abandoned, limiting green-minded buyers
- Charter short-mast version may undercut performance expectations
- No fittings aft of coachroof beyond davits limits aft-deck gear mounting
