Cal's Evals » LAGOON 380

Release Date: 1/2/2010

Lagoon 380


The Lagoon 380 is a late 2000s update of a 1999 cruising catamaran design. It displays very contemporary styling with vertical stems and sloped-off sterns with the customary integral boarding steps. The deckhouse is fitted with vertical wrap-around windows that are common to the Lagoon family of cruising catamarans. Windward performance is sacrificed for cruising convenience with the outfitting of the boat with low aspect ratio keels.

The Multihull Dynamics, Inc. (MDI) evaluation of the boat in comparison with the averages of 34 cruising catamarans with comparable waterline lengths is as follows:


Displacement: 7.59 tons [average 5.14 tons average (range 2.68 to 9.7 tons)]


Length Overall: 37.92 feet [average 38.06 feet (range is 36 to 44 feet)]


Length at Waterline: 36.07 feet [average 36.05 feet (range is 35.58 to 36.7)]


Sail Area (Main plus 100% fore-triangle): 720 sq. ft. [average 777 sq. ft. (range is 522 to 1086)]


Sail Area/Displacement Ratio: 17.42 [average 25.31 (range is 14.38 to 41.68)]


Beam between hull centerlines: 16.91 ft. [average 17.82 ft. (range is 15.01 to 22.99)]


Bridgedeck Clearance (Unknown) [30 in. is nominal for 36 ft. LWL catamarans]


Hull Waterline Length/ Beam ratio: 7.98 [average 10.16 (range is 6.92 to 13.73)]


Base Speed: 8.8 knots [average 10.06 (range is 8.13 to 12.1)]


Texel Rating: 149 [average 127(range is 100 to 163)]


Bruce Number: 1.05 [average 1.25(range is 0.95 to 1.62)]


Stability Speed: 24.74 knots [average 19.68 (range is 13.21 to 28.29)]


Kelsall Stability Speed: 41.62 knots [33.11 average (range is 22.21 to 47.59)]


The other boats used for comparison are the Oasis 380 (heavy boat, lightly powered), Seawind 1160, Ocean Cheetah 37, KSS 38ma, Cosmos 1100, Seawind 1000XX, Shuttle 40, Transit, Wilderness 1100, KSS 38S, Ambercat 1100, Apache 41, Patty Cat II (a true racing cat), Hughes 36, Jaguar 36, Ksenia 109, Louisiane 37, Oram 36, Waller 1160, Cat2fold, TC 11.5, Meander, Seagull, SK37, Spirited 380, Oceanspirit 42, Simpson 12, Easy Catamaran 11.6, Nimbus, Surtees 13M, Crowther 37, Coral Cove 40 and Fastcat 40.

The Lagoon 380 is a heavy boat with lower than average sail area. Combined with the low aspect ratio keels, this boat is clearly a cruising design. It has higher than average Stability Speed, but nearly the lowest performance (Base Speed) in the group.

The Lwl/Bh (hull waterline length to beam) ratio of under 8, it is in the cruising category by Charles Kanters method of categorizing multihulls, but research on boat hulls shows that this beamy a boat will produce an appreciable bow wave that will limit speed to that of displacement monohulls of its size. This could be considered a desecration of the fundamental multihull concept.

Calvin H. Markwood                             
Engineering Analyst
Multihull Dynamics, Inc.

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