J/120
J/Boats · Rod Johnstone · 1994
Updated
The J/120 is a 12.24 m semi-displacement racing yacht designed by Rod Johnstone and built by J/Boats, first launched in 1994. It races in Class B. Across the measured fleet it goes better than its own numbers promise, ahead of 74% of the designs it races against.
Goes better than its own measurements promise, and does it better than 74% of the boats it races against.
25th of 92 in its class.
Updated — First Race Edge for this design. Enough boats of this design have now been measured on the current scale to rank it.
This design has been found in real race results — 2 starts across 2 events — not only in measurement files.
Length
12.24 m
40′ 2″
Beam
3.67 m
Draft
2.17 m
Displacement
7.0 t
Sail area
98 m²
On the podium
Where a J/120 finishes when she goes racing.
0
Wins
0
Seconds
0
Thirds
2
Starts
Not enough races yet for a percentage — these are the counts so far. We keep collecting results, so this will fill in.
Read from 2 starts by 2 boats between 2019 and 2024, counting races with six boats or more.
Recent regattas
The latest events where a J/120 was on the start line, named as the organisers publish them.
- ORC DH World Championship2024
50 Mijl Doublehanded2019
Raced one we are missing?
Report a regattaRound the buoys, or offshore
A short windward-leeward and a night at sea ask different things of a boat. Here is how this one does in each.
Round the buoys
—
Not enough data yet: no races of 10 NM or less carry a published distance.
Offshore & coastal
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Not enough data yet: 1 race over 10 NM carry a published distance.
Who she races against
The designs a J/120 actually lines up with, most often first. The bar shows how those meetings ended.
Met too few times for a figure:
Dehler 30 OD (2 meetings), Figaro 2 (1 meeting), Arcona 385 (1 meeting), JPK 10.80 (1 meeting), JPK 10.30 (3 meetings), Corby 33 (1 meeting), Elan S5 (1 meeting), Elan 350 (2 meetings), Sun Fast 3300 (Andrieu) (4 meetings), Sun Fast 3600 (1 meeting), J/109 (1 meeting), Dehler 39 (Judel/Vrolijk) (1 meeting), X-40 (1 meeting), X-412 (1 meeting), Dehler 38 (Judel/Vrolijk) (1 meeting), J/122 (2 meetings), F & F 65 (2 meetings), Corby 36 (1 meeting), J/111 (1 meeting)
Speed at every angle
The shape of this design's speed, drawn from the measured fleet. Pick a wind and watch it stretch.
Upwind VMG
5.83
36°
Beam reach
9.01
90°
Broad reach
10.85
135°
Downwind VMG
8.31
170°
Speed in knots at 20 knots of true wind. Green marks the angles that pay: the closest useful beat and the deepest run worth sailing.
Where it wins and where it pays
Every boat is judged against its own measurements — length, weight, sail area. The quicker those say it should be, the more it has to deliver just to break even. Going fast is not enough: it has to go faster than its own numbers promised.
This design is even-tempered. It rewards preparation and crew work more than it rewards picking the right day.
Where it gains
Its best ground is on a broad reach once it pipes up, where it does more than its size and sail area promise, and by a margin worth having. It holds that advantage upwind as well, so the gain is not down to one leg of the course.
Where it pays
There is no condition where it falls away badly, which is worth something over a season of mixed weather.
Above the line it delivers more than promised and gains on the fleet. Below, it falls short. Move the wind: plenty of boats sit on one side in the light and the other when it blows.
Full width is 0.6 kn either way.
At 10 knots this design makes back more than its rating asks on the broad reach.
How fast is a J/120
Boat speed in knots, by true wind angle and wind strength.
| Angle | 6 kn | 10 kn | 14 kn | 20 kn |
|---|---|---|---|---|
| Beat VMG | 3.77 | 5.19 | 5.64 | 5.83 |
| 52° | 5.77 | 7.43 | 7.82 | 8.01 |
| 60° | 6.09 | 7.61 | 8.01 | 8.23 |
| 75° | 6.29 | 7.73 | 8.25 | 8.62 |
| 90° | 6.21 | 7.83 | 8.39 | 9.01 |
| 110° | 6.23 | 8.06 | 8.77 | 9.67 |
| 120° | 6.13 | 8.05 | 8.97 | 10.18 |
| 135° | 5.45 | 7.73 | 8.80 | 10.85 |
| 150° | 4.59 | 6.89 | 8.17 | 9.59 |
| Run VMG | 3.98 | 5.97 | 7.13 | 8.31 |
How they are set up
The range each sail spans across the fleet.
Nearly all carry a folding propeller. A bowsprit is standard across the fleet. Crew weight is declared around 820 kg.
Rigging
J/120 rig and sail dimensions
A J/120 carries 14.17 m of mainsail hoist on a 5.42 m boom, a forestay 15.33 m above the deck and a 6.60 m bowsprit. Typical figures across the 41 boats measured under the current VPP, with the range each one spans.
Rig
Sails
The spinnaker spreads widest of all — 132 to 166 m² depending on bowsprit and set-up. Before ordering a sail, read the figure on your own measurement record rather than the typical one for the design.