First 25 Fin keel

Sailboat specifications

The First 25 is a 24’10” (7.55m) cruiser-racer sailboat designed by Groupe Finot (France). She was built between 1979 and 1984 by Bénéteau (France) with 1115 hulls completed. The Fin keel version adopts a classical fin configuration, the easiest option to provide a low center of gravity.

The First 25 is as well listed, on Boat-Specs.com, in Swing keel version (see all the versions compared).

First 25's main features

Model: First 25
Version: Fin keel
Hull type: Monohull
Category: Cruiser-racer sailboat
Sailboat builder: Bénéteau
Sailboat designer: Groupe Finot
Sailboat range: First
Country: France
Construction: GRP (glass reinforced polyester):
- Hull: Single skin fiberglass polyester
- Deck: Sandwich balsa fiberglass polyester
Number of hulls built: 1115
First built hull: 1979
Last built hull: 1984
Appendages: Keel : fin without bulb
Helm: Single tiller
Rudder: Single transom hung rudder
Unsinkable: No
Trailerable: No
Former French navigation category: 3
Standard public price ex. VAT (indicative only): N/A €

First 25's main dimensions

Overall length: 28’ 1”8.56 m
Hull length: 24’ 10”7.55 m
Waterline length: 21’ 4”6.5 m
Beam (width): 9’ 2”2.8 m
Draft: 4’ 4”1.3 m
Light displacement (M_LC): 3968 lb1800 kg
Ballast weight: 1543 lb700 kg
French customs tonnage: 5.43 Tx

First 25's rig and sails

Upwind sail area: 388 ft²36 m²
Downwind sail area: 671 ft²62.3 m²
Mainsail area: 132 ft²12.3 m²
Genoa area: 255 ft²23.7 m²
Jib area: 105 ft²9.8 m²
Stormjib area: 47 ft²4.4 m²
Symmetric spinnaker area: 538 ft²50 m²
Rigging type: Sloop Marconi masthead
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 25'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.: 262 ft²/T24.33 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.: 453 ft²/T42.1 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.: 186
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.: 39 %
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.: 6.19 knots