Dufour 1800 Deep draft

Sailboat specifications

The Dufour 1800 is a 24’11” (7.6m) cruising sailboat designed by Laurent Cordelle (France) and Michel Dufour (France). She was built between 1979 and 1982 by Dufour (France). The Deep draft version displays a deeper fin allowing a lower center of gravity and extra performance especially upwind.

The Dufour 1800 is as well listed, on Boat-Specs.com, in Shoal draft version (see all the versions compared).

Dufour 1800's main features

Model: Dufour 1800
Version: Deep draft
Hull type: Monohull
Category: Coastal cruising sailboat
Sailboat builder: Dufour
Sailboat designer: Laurent Cordelle & Michel Dufour
Country: France
Construction: GRP (glass reinforced polyester):
- Hull: Single skin fiberglass polyester
- Deck: Sandwich balsa fiberglass polyester
Number of hulls built: About 200
First built hull: 1979
Last built hull: 1982
Appendages: Keel : fin without bulb
Helm: Single tiller
Rudder: Single spade rudder
Unsinkable: No
Trailerable: No
Former French navigation category: 3
Standard public price ex. VAT (indicative only): N/A €

Dufour 1800's main dimensions

Hull length: 24’ 11”7.6 m
Waterline length: 22’6.7 m
Beam (width): 8’ 7”2.62 m
Waterline beam (width): 6’ 11”2.1 m
Draft: 4’ 4”1.3 m
Mast height from D_WL: 35’ 5”10.8 m
Fore freeboard: 3’0.92 m
Mid-ship freeboard: 2’ 8”0.83 m
Light displacement (M_LC): 4321 lb1960 kg
Maximum displacement (M_LDC): 5401 lb2450 kg
Ballast weight: 1653 lb750 kg
Ballast type: Cast iron
French customs tonnage: 4.37 Tx

Dufour 1800's rig and sails

Upwind sail area: 333 ft²30.93 m²
Downwind sail area: 531 ft²49.29 m²
Mainsail area: 154 ft²14.29 m²
Genoa area: 179 ft²16.64 m²
Jib area: 101 ft²9.37 m²
Symmetric spinnaker area: 377 ft²35 m²
I iFore triangle height (from mast foot to fore stay top attachment): 27’ 7”8.4 m
J iFore triangle base (from mast foot to bottom of forestay): 8’ 6”2.58 m
P iMainsail hoist measurement (from tack to head): 27’ 11”8.5 m
E iMainsail foot measurement (from tack to clew): 9’ 10”3 m
Rigging type: Sloop Marconi 7/8
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

Dufour 1800'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.: 18.1
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.: 9.0
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.: 213 ft²/T19.75 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.: 339 ft²/T31.47 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.: 185
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.: 38 %
Wetted area: 145 ft²13.45 m²
Maximum transverse section: 8 ft²0.76 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.: 6.28 knots