The Lagoon 400 S2 2012 vs Lagoon 51 2021 comparison sits squarely in the category of decisions where specs alone won't tell the whole story — intended use, storage, and long-term ownership costs all factor in.
Size is the most obvious dividing line here. The Lagoon 51 2021 measures 50,4 feet overall (2021), giving it roughly 11,0 additional feet of deck space compared to the Lagoon 400 S2 2012 at 39,4 feet (2012). Weight tells a clearer story for trailering families: the Lagoon 51 2021 tips the scales at 43 910 lbs — 21 092 lbs less than the Lagoon 400 S2 2012 at 22 818 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
The power gap is worth calling out. Rated to 80 hp, the Lagoon 51 2021 has a 51-hp advantage over the Lagoon 400 S2 2012's 29-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Lagoon 51 2021 carries 137 gallons versus 106 gallons in the Lagoon 400 S2 2012. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Lagoon 51 2021 is rated for 15 passengers, while the Lagoon 400 S2 2012 caps at 12. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Lagoon 51 2021 could be the deciding factor.
Displacement is where these two sailboats genuinely part ways. The Lagoon 51 2021 displaces 43 910 lbs — a 21 092-lb difference over the Lagoon 400 S2 2012 at 22 818 lbs. That gap separates two entirely different categories of sailing: the heavier boat is built for offshore passage-making and load-carrying, while the lighter hull rewards performance sailing and easier handling in lighter air.
Both boats draw a similar depth — 4,0 ft and 4,6 ft respectively. Marina access and anchorage options should be broadly equivalent between the two.
The Lagoon 400 S2 2012 uses fractional_rig_sloop rigging. For auxiliary power the Lagoon 51 2021 carries a 80-hp engine against 29 hp on the Lagoon 400 S2 2012. Motoring range and ability to punch through a foul current or enter a tight marina under power will favour the more powerful installation.
For extended cruising, water capacity matters: the Lagoon 51 2021 carries 219 gallons versus 79 gallons on the Lagoon 400 S2 2012 — a significant advantage on longer passages where watermaker or provisioning stops aren't guaranteed.
Bottom line: The Lagoon 51 2021 is the offshore and bluewater choice — at 43 910 lbs displacement and 50 ft it has the load capacity, range, and seakeeping for extended passages. The Lagoon 400 S2 2012 at 22 818 lbs is the more nimble, accessible option — easier to single-hand and better suited to coastal and inland sailing.