First 21.7 Swing keel

Sailboat specifications

The First 21.7 is a 20’6” (6.25m) cruiser-racer sailboat designed by Finot Conq Architectes (France). She was built between 2004 and 2008 by Bénéteau (France). The Swing keel version features an appendage configuration without compromise between draft and performance. The only drawbacks are the space is taken inside and the effort needed to lift the keel....

First 21.7's main features

Model: First 21.7
Version: Swing keel
Hull type: Monohull
Category: Cruiser-racer sailboat
Sailboat builder: Bénéteau
Sailboat designer: Finot Conq Architectes
Sailboat range: First
Country: France
Construction: GRP (glass reinforced polyester):
- Hull: Single skin fiberglass polyester
- Deck: Sandwich balsa fiberglass polyester
First built hull: 2004
Last built hull: 2008
Appendages: Lifting keel : swing keel
Helm: Single tiller
Rudder: Twin spade rudders
Unsinkable: No
Trailerable: Yes
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: C
Former French navigation category: 3
Standard public price ex. VAT (indicative only): N/A €

First 21.7's main dimensions

Overall length: 21’6.4 m
Hull length: 20’ 6”6.25 m
Waterline length: 19’ 8”6 m
Beam (width): 8’ 1”2.48 m
Draft: 5’ 11”1.8 m
Draft when appendages up: 2’ 4”0.7 m
Mast height from D_WL: 34’ 1”10.4 m
Light displacement (M_LC): 2745 lb1245 kg
Ballast weight: 772 lb350 kg
Ballast type: Cast iron
French customs tonnage: 3.99 Tx

First 21.7's rig and sails

Upwind sail area: 271 ft²25.2 m²
Downwind sail area: 523 ft²48.57 m²
Mainsail area: 149 ft²13.8 m²
Genoa area: 123 ft²11.4 m²
Symmetric spinnaker area: 374 ft²34.77 m²
I iFore triangle height (from mast foot to fore stay top attachment): 28’ 2”8.59 m
J iFore triangle base (from mast foot to bottom of forestay): 7’ 11”2.4 m
P iMainsail hoist measurement (from tack to head): 27’ 2”8.3 m
E iMainsail foot measurement (from tack to clew): 9’ 5”2.85 m
Rigging type: Sloop Marconi 9/10
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

First 21.7'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.: 234 ft²/T21.77 m²/T
Downwind 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.: 452 ft²/T41.97 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.: 163
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.: 28 %
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.: 5.95 knots