Oyster SJ41 Fractional rigging

Sailboat specifications

The Oyster SJ41 is a 39’8” (12.09m) cruiser-racer sailboat designed by Stephen Jones Yacht Design (United Kingdom). She was built between 1980 and 1987 by Oyster (United Kingdom) with 23 hulls completed. The Fractional rigging version features 3/4 rig allowing finer sail trimming options and lower IOR rating.

The Oyster SJ41 is as well listed, on Boat-Specs.com, in Mast head rigging version (see all the versions compared).

Oyster SJ41's main features

Model: Oyster SJ41
Version: Fractional rigging
Hull type: Monohull
Category: Offshore cruiser-racer sailboat
Sailboat builder: Oyster
Sailboat designer: Stephen Jones Yacht Design
Sailboat collection: One Ton class
Country: United Kingdom
Construction: Hull and deck: GRP (glass reinforced polyester)
Number of hulls built: 23
First built hull: 1980
Last built hull: 1987
Appendages: Keel : fin without bulb
Helm: Single helm wheel
Rudder: Single rudder on skeg
Unsinkable: No
Trailerable: No
Standard public price ex. VAT (indicative only): N/A €

Oyster SJ41's main dimensions

Hull length: 39’ 8”12.09 m
Waterline length: 33’ 7”10.25 m
Beam (width): 13’ 7”4.15 m
Draft: 6’ 11”2.1 m
Light displacement (M_LC): 17086 lb7750 kg
Ballast weight: 7716 lb3500 kg
Ballast type: Lead

Oyster SJ41's rig and sails

Upwind sail area: 648 ft²60.2 m²
Rigging type: Sloop Marconi 3/4
Rotating spars: No
Number of levels of spreaders: 2
Spreaders angle: 0 °
Running backstays: 2 set(s)
Spars construction: Aluminum spars
Standing rigging: 1x19 strand wire

Oyster SJ41'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.: 165 ft²/T15.37 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.: 204
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.: 45 %
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.: 7.77 knots