Centaur Ketch

Sailboat specifications

The Centaur is a 25’11” (7.9m) cruising sailboat designed by John Laurent Giles (United Kingdom). She was built between 1969 and 1980 by Westerly (United Kingdom) with 2444 hulls completed. The Ketch version displays a divided sail plan guarantying less effort and better balance adjustment.

The Centaur is as well listed, on Boat-Specs.com, in Sloop version (see all the versions compared).

Centaur's main features

Model: Centaur
Version: Ketch
Hull type: Monohull
Category: Cruising sailboat
Sailboat builder: Westerly
Sailboat designer: John Laurent Giles
Country: United Kingdom
Construction: Hull and deck: GRP (glass reinforced polyester)
Number of hulls built: 2444
First built hull: 1969
Last built hull: 1980
Appendages: Twin keel : fin without bulb
Helm: Single tiller
Rudder: Single spade rudder
Unsinkable: No
Trailerable: No
Former French navigation category: 2
Standard public price ex. VAT (indicative only): N/A €

Centaur's main dimensions

Overall length: 27’ 11”8.5 m
Hull length: 25’ 11”7.9 m
Waterline length: 21’ 8”6.6 m
Beam (width): 8’ 6”2.6 m
Draft: 3’0.9 m
Mast height from D_WL: 32’ 6”9.9 m
Light displacement (M_LC): 6702 lb3040 kg
Ballast weight: 2800 lb1270 kg
Ballast type: Cast iron
French customs tonnage: 6.65 Tx

Centaur's rig and sails

Upwind sail area: 384 ft²35.65 m²
Mainsail area: 110 ft²10.2 m²
Mizzen sail area: 37 ft²3.45 m²
Genoa area: 237 ft²22 m²
Solent area: 173 ft²16.1 m²
Jib area: 110 ft²10.2 m²
Stormjib area: 46 ft²4.25 m²
Rigging type: Sloop Marconi masthead
Mast configuration: Deck stepped mast
Rotating spars: No
Number of levels of spreaders: 1
Spreaders angle: 0 °
Spars construction: Aluminum spars
Standing rigging: 1x19 strand wire continuous

Centaur'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.: 183 ft²/T16.99 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.: 299
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.: 42 %
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.: 6.24 knots