J/42
J/Boats · Rod Johnstone · 1996
Updated
The J/42 is a 12.71 m displacement racing yacht designed by Rod Johnstone and built by J/Boats, first launched in 1996. It races in Class B.
Length
12.71 m
41′ 8″
Beam
3.72 m
Draft
2.01 m
Displacement
8.5 t
Sail area
97 m²
On the podium
Where a J/42 finishes when she goes racing.
Not enough data yet to show how this design finishes. It has not been found in the race results we have collected so far.
Recent regattas
The latest events where a J/42 was on the start line, named as the organisers publish them.
No regattas found yet.
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
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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: no races over 10 NM carry a published distance.
Who she races against
The designs a J/42 actually lines up with, most often first. The bar shows how those meetings ended.
Not enough data yet to say who this design races against. No result we have collected puts it on the water beside another design we track.
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
5.56
38°
Beam reach
8.59
90°
Broad reach
9.30
135°
Downwind VMG
7.98
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.
Soft conditions suit it. Early-season racing and morning breezes play to its strengths; once it pipes up the fleet comes back to it.
Where it gains
Its best ground is upwind in a strong breeze, where it outruns what it looks like on paper, and by a margin worth having.
Where it pays
It falls short off the wind once it pipes up, giving away time it never gets back. That is a displacement hull working to its designed speed.
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 0.4 kn either way.
At 10 knots this design makes back more than its rating asks on the beam reach.
How fast is a J/42
Boat speed in knots, by true wind angle and wind strength.
| Angle | 6 kn | 10 kn | 14 kn | 20 kn |
|---|---|---|---|---|
| Beat VMG | 3.56 | 4.90 | 5.38 | 5.56 |
| 52° | 5.48 | 7.12 | 7.58 | 7.75 |
| 60° | 5.80 | 7.31 | 7.76 | 7.96 |
| 75° | 6.02 | 7.46 | 7.96 | 8.30 |
| 90° | 5.96 | 7.51 | 8.07 | 8.59 |
| 110° | 5.80 | 7.65 | 8.36 | 9.14 |
| 120° | 5.65 | 7.55 | 8.33 | 9.44 |
| 135° | 5.06 | 7.17 | 8.08 | 9.30 |
| 150° | 4.25 | 6.38 | 7.66 | 8.77 |
| Run VMG | 3.68 | 5.54 | 6.88 | 7.98 |
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 670 kg.
Rigging
J/42 rig and sail dimensions
A J/42 carries 14.17 m of mainsail hoist on a 5.49 m boom, a forestay 15.34 m above the deck and a 5.54 m bowsprit. Typical figures across the 4 boats measured under the current VPP, with the range each one spans.
Rig
Sails
The spinnaker spreads widest of all — 102 to 145 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.