First 51 Wing keel

Sailboat specifications

The First 51 is a 50’ (15.23m) cruiser-racer sailboat designed by Frers Naval Architecture & Engineering (Argentina). She was built since 1986 (and now discontinued) by Bénéteau (France). The Wing keel version is offered with a short keel fitted with large winglets. This configuration provides an interesting draft / low center of gravity / upwind performance trade-off.

The First 51 is as well listed, on Boat-Specs.com, in S / Deep draft version (see all the versions compared).

First 51's main features

Model: First 51
Version: Wing keel
Hull type: Monohull
Category: Offshore cruiser-racer sailboat
Sailboat builder: Bénéteau
Sailboat designer: Frers Naval Architecture & Engineering
Sailboat range: First
Country: France
Construction: GRP (glass reinforced polyester):
- Hull: Single skin fiberglass polyester
- Deck: Sandwich balsa fiberglass polyester
First built hull: 1986
Last built hull: Discontinued
Appendages: Keel : wing keel
Helm: Twin helm wheels
Rudder: Single spade rudder
Unsinkable: No
Trailerable: No
Former French navigation category: 1
Standard public price ex. VAT (indicative only): N/A €

First 51's main dimensions

Overall length: 51’ 4”15.63 m
Hull length: 50’15.23 m
Waterline length: 43’ 1”13.15 m
Beam (width): 14’ 11”4.55 m
Waterline beam (width): 12’ 1”3.7 m
Draft: 5’ 11”1.81 m
Mast height from D_WL: 73’ 10”22.5 m
Light displacement (M_LC): 30865 lb14000 kg
Ballast weight: 14220 lb6450 kg
Ballast type: Cast iron

First 51's rig and sails

Upwind sail area: 1538 ft²142.84 m²
Downwind sail area: 2719 ft²252.6 m²
Mainsail area: 566 ft²52.6 m²
Genoa area: 971 ft²90.24 m²
Symmetric spinnaker area: 2153 ft²200 m²
I iFore triangle height (from mast foot to fore stay top attachment): 64’19.5 m
J iFore triangle base (from mast foot to bottom of forestay): 20’6.1 m
P iMainsail hoist measurement (from tack to head): 56’ 5”17.2 m
E iMainsail foot measurement (from tack to clew): 18’ 5”5.6 m
Rigging type: Sloop Marconi masthead
Mast configuration: Keel stepped mast
Rotating spars: No
Number of levels of spreaders: 3
Spreaders angle: 0 °
Spars construction: Aluminum spars
Standing rigging: Single-strand (ROD)

First 51's performances

HN (French rating) iHN or "Handicap Nationale" is an empirical rating system used in France allowing various monohulls, of different sizes and designs, to race each other fairly. It is particularly suitable for cruiser and cruiser-racer. Therefore, by comparing these values, we can have an indication of the relative speed of 2 boats.: 28.0
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.: 265 ft²/T24.59 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.: 468 ft²/T43.49 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.: 174
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.: 46 %
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.: 8.80 knots