Jouët 680 Fin keel

Sailboat specifications

The Jouët 680 is a 21’6” (6.55m) cruising sailboat designed by Jean Berret (France). She was built between 1978 and 1984 by Yachting France (France) with 426 hulls completed. The Fin keel version adopts a classical fin configuration, the easiest option to provide a low center of gravity.

The Jouët 680 is as well listed, on Boat-Specs.com, in Centerboard (Trunk) version (see all the versions compared).

Jouët 680's main features

Model: Jouët 680
Version: Fin keel
Hull type: Monohull
Category: Cruising sailboat
Sailboat builder: Yachting France
Sailboat designer: Jean Berret
Sailboat range: Jouët
Country: France
Construction: GRP (glass reinforced polyester):
- Hull: Single skin fiberglass polyester
- Deck: Sandwich balsa fiberglass polyester
Number of hulls built: 426
First built hull: 1978
Last built hull: 1984
Appendages: Keel : fin without bulb
Helm: Single tiller
Rudder: Single transom hung rudder
Unsinkable: No
Trailerable: Yes
Former French navigation category: 3
Standard public price ex. VAT (indicative only): N/A €

Jouët 680's main dimensions

Overall length: 24’7.32 m
Hull length: 21’ 6”6.55 m
Waterline length: 19’ 10”6.04 m
Beam (width): 7’ 11”2.42 m
Waterline beam (width): 7’2.14 m
Draft: 3’ 7”1.1 m
Fore freeboard: 2’ 10”0.85 m
Mid-ship freeboard: 2’ 10”0.86 m
Light displacement (M_LC): 3307 lb1500 kg
Ballast weight: 1422 lb645 kg
Ballast type: Cast iron interior ballast with steel centerboard
French customs tonnage: 3.53 Tx

Jouët 680's rig and sails

Upwind sail area: 270 ft²25.04 m²
Downwind sail area: 447 ft²41.52 m²
Mainsail area: 129 ft²12.02 m²
Genoa area: 140 ft²13.02 m²
Jib area: 90 ft²8.4 m²
Stormjib area: 36 ft²3.3 m²
Symmetric spinnaker area: 318 ft²29.5 m²
P iMainsail hoist measurement (from tack to head): 24’ 4”7.4 m
E iMainsail foot measurement (from tack to clew): 9’ 6”2.9 m
Rigging type: Sloop Marconi 7/8
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

Jouët 680's performances

IOR rating iIOR, or International Offshore Rule, was a measurement rule system used internationally for ocean racing. It allows boats of different sizes and designs to race each other fairly. Therefore, by comparing these values, we can have an indication of the relative speed of 2 boats.: 16.0
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.: 8.0
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.: 206 ft²/T19.11 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.: 341 ft²/T31.69 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.: 193
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.: 43 %
Wetted area: 113 ft²10.51 m²
Maximum transverse section: 7 ft²0.65 m²
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.: 5.97 knots