J/121

Sailboat specifications

The J/121 is a 40’ (12.2m) cruiser-racer sailboat designed by Alan Johnstone (United States). She was built since 2017 (and now discontinued) by J/Boats (United States). She has been awarded "2018 - Sailing World - Boat of the Year: Best Crossover" and "2018 - SAIL magazine - Best Performance Boat 30 to 40ft".

J/121's main features

Model

J/121

Hull type

Monohull

Category

Offshore cruiser-racer sailboat

Sailboat builder

J/Boats

Sailboat designer

Alan Johnstone

Country

United States

Construction

GRP (glass reinforced polyester):
- Hull: Sandwich Core-Cell fiberglass polyester (vacuum infusion)
- Deck: Sandwich Core-Cell fiberglass polyester (vacuum infusion)

First built hull

2017

Last built hull

Discontinued

Award(s)

2018: Sailing World - Boat of the Year: Best Crossover
2018: SAIL magazine - Best Performance Boat 30 to 40ft

Appendages

Keel : L-shaped keel (with bulb)

Helm

Twin helm wheels

Rudder

Single spade rudder

Unsinkable

Trailerable

EC design category iThe CE design category indicates the ability to cope with certain weather conditions (the sailboat is designed for these conditions) A: Wind < force 9, Waves < 10m B: Wind < force 8, Waves < 8m C: Wind < force 6, Waves < 4m D: Wind < force 4, Waves < 0,5m

Standard public price ex. VAT (indicative only)

N/A €

J/121's main dimensions

Hull length: 40’12.2 m
Waterline length: 35’ 10”10.9 m
Beam (width): 12’ 4”3.75 m
Draft: 7’ 1”2.15 m
Light displacement (M_LC): 11464 lb5200 kg
Ballast type: Cast iron fin with lead bulb
Water ballast: Lateral water ballasts
Water ballast capacity: 2100.4 gal380 liters

J/121's rig and sails

Upwind sail area: 969 ft²90 m²
Downwind sail area: 2153 ft²200 m²
Rigging type: Sloop Marconi 7/8
Mast configuration: Keel stepped mast
Rotating spars: No
Number of levels of spreaders: 2
Spreaders angle: Swept-back
Spars construction: Carbon fiber spars
Standing rigging: Single-strand (ROD) discontinuous

J/121'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.: 323 ft²/T29.99 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.: 717 ft²/T66.63 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.: 114
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.: 8.01 knots