Océanis 311 Keel and centerboard

Sailboat specifications

The Océanis 311 is a 31’2” (9.5m) cruising sailboat designed by Finot Conq Architectes (France). She was built between 1997 and 2003 by Bénéteau (France) with 1042 hulls completed. The Keel and centerboard version features a centerboard inside of a short fin-keel allowing shoal draft while maintaining upwind capabilities.

The Océanis 311 is as well listed, on Boat-Specs.com, in Fin keel version (see all the versions compared).

Océanis 311's main features

Model: Océanis 311
Version: Keel and centerboard
Hull type: Monohull
Category: Cruising sailboat
Sailboat builder: Bénéteau
Sailboat designer: Finot Conq Architectes
Sailboat range: Océanis
Country: France
Construction: GRP (glass reinforced polyester):
- Hull: Single skin fiberglass polyester
- Deck: Sandwich balsa fiberglass polyester
Number of hulls built: 1042
First built hull: 1997
Last built hull: 2003
Appendages: Centerboard : pivoting centerboard in the keel
Helm: Single helm wheel
Rudder: Twin spade rudders
Unsinkable: No
Trailerable: No
EC design category iThe CE design category indicates the ability to cope with certain weather conditions (the sailboat is designed for these conditions) A: Wind < force 9, Waves < 10m B: Wind < force 8, Waves < 8m C: Wind < force 6, Waves < 4m D: Wind < force 4, Waves < 0,5m: B
Standard public price ex. VAT (indicative only): N/A €

Océanis 311's main dimensions

Overall length: 32’ 4”9.85 m
Hull length: 31’ 2”9.5 m
Waterline length: 28’ 11”8.8 m
Beam (width): 10’ 7”3.23 m
Draft: 6’ 7”2 m
Draft when appendages up: 2’ 7”0.8 m
Light displacement (M_LC): 8708 lb3950 kg
Ballast weight: 3086 lb1400 kg
Ballast type: Cast iron
French customs tonnage: 9.30 Tx

Océanis 311's rig and sails

Upwind sail area: 538 ft²50 m²
Mainsail area: 277 ft²25.7 m²
Genoa area: 262 ft²24.3 m²
Rigging type: Sloop Marconi 19/20
Mast configuration: Deck stepped mast
Rotating spars: No
Number of levels of spreaders: 1
Spreaders angle: Swept-back
Spars construction: Aluminum spars
Standing rigging: 1x19 strand wire continuous

Océanis 311's performances

Upwind sail area to displacement iThe ratio sail area to displacement is obtained by dividing the sail area by the boat's displaced volume to the power two-thirds. The ratio sail area to displacement can be used to compare the relative sail plan of different sailboats no matter what their size. Upwind: under 18 the ratio indicates a cruise oriented sailboat with limited performances especially in light wind, while over 25 it indicates a fast sailboat.: 215 ft²/T20.01 m²/T
Displacement-length ratio (DLR) iThe Displacement Length Ratio (DLR) is a figure that points out the boat's weight compared to its waterline length. The DLR is obtained by dividing the boat's displacement in tons by the cube of one one-hundredth of the waterline length (in feet). The DLR can be used to compare the relative mass of different sailboats no matter what their length: a DLR less than 180 is indicative of a really light sailboat (race boat made for planning), while a DLR greater than 300 is indicative of a heavy cruising sailboat.: 164
Ballast ratio iThe Ballast ratio is an indicator of stability; it is obtained by dividing the boat's displacement by the mass of the ballast. Since the stability depends also of the hull shapes and the position of the center of gravity, only the boats with similar ballast arrangements and hull shapes should be compared. The higher the ballast ratio is, the greater is the stability.: 35 %
Critical hull speed iAs a ship moves in the water, it creates standing waves that oppose its movement. This effect increases dramatically the resistance when the boat reaches a speed-length ratio (speed-length ratio is the ratio between the speed in knots and the square root of the waterline length in feet) of about 1.2 (corresponding to a Froude Number of 0.35) . This very sharp rise in resistance, between speed-length ratio of 1.2 to 1.5, is insurmountable for heavy sailboats and so becomes an apparent barrier. This leads to the concept of "hull speed". The hull speed is obtained by multiplying the square root of the waterline length (in feet) by 1.34.: 7.20 knots