A 31
Archambault · Joubert/Nivelt · 2009
Updated
The A 31 is a 9.55 m semi-displacement racing yacht designed by Joubert/Nivelt and built by Archambault, first launched in 2009. It races in Class C. Across the measured fleet it goes better than its own numbers promise, ahead of 87% of the designs it races against.
Goes better than its own measurements promise, and does it better than 87% of the boats it races against.
22nd of 159 in its class.
This design has been found in real race results — 4 starts across 3 events — not only in measurement files.
Length
9.55 m
31′ 4″
Beam
3.24 m
Draft
1.98 m
Displacement
3.2 t
Sail area
52 m²
On the podium
Where a A 31 finishes when she goes racing.
1
Wins
0
Seconds
1
Thirds
4
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 4 starts by 4 boats between 2015 and 2024, counting races with six boats or more.
Recent regattas
The latest events where a A 31 was on the start line, named as the organisers publish them.
- ORC DH World Championship2024
Regata dei Cinque Fari2018
Hollænderseilasen2015
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: 2 races over 10 NM carry a published distance.
Who she races against
The designs a A 31 actually lines up with, most often first. The bar shows how those meetings ended.
Also met, too few times for a figure:
X-34 (5 meetings), First 36.7 (2 meetings), Dufour 34 (3 meetings), Farr 30 (1 meeting), First 34.7 (1 meeting), Bavaria Match 38 (1 meeting), Elan 37 (2 meetings), Xp 33 (1 meeting), Farr 31 (1 meeting), X-35 (2 meetings), First 31.7 (2 meetings), Linjett 33 (1 meeting), First 30 (Kouyoumdjian) (1 meeting), Sun Fast 3200 (1 meeting), X-362 (2 meetings), Elan 333 (1 meeting), Archambault 31 (1 meeting), X-95 (1 meeting), Arcona 370 (1 meeting), J/92 (1 meeting), Dehler 33 (2 meetings), Finngulf 37 (2 meetings), Dehler 34 (Judel/Vrolijk) (2 meetings), Hanse 371 (2 meetings), Dufour 425 (2 meetings), Bavaria Cruiser 38 (2 meetings), Bavaria Cruiser 40 S (2 meetings), Elan 350 (2 meetings), X-41 (2 meetings), Cookson 50 (1 meeting), J/122 (1 meeting), Comet 41 (1 meeting), Elan 400 (1 meeting), Comet 45 (1 meeting)
Some of the boats it races against
How the A 31 has fared against each of them, boat against boat on corrected time. Ordered by how often the two meet, not by who wins.
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
5.10
38°
Beam reach
8.27
90°
Broad reach
9.95
135°
Downwind VMG
8.03
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 is a boat that wants breeze. Give it a fresh day and long legs and it delivers more than it promised; in a drifter it is working uphill.
Where it gains
Its best ground is off the wind in a strong breeze, where it does more than its size and sail area promise, and by a margin worth having. It holds that advantage running deep 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 1.0 kn either way.
At 10 knots this design makes back more than its rating asks on the downwind.
How fast is a A 31
Boat speed in knots, by true wind angle and wind strength.
| Angle | 6 kn | 10 kn | 14 kn | 20 kn |
|---|---|---|---|---|
| Beat VMG | 3.40 | 4.64 | 5.01 | 5.10 |
| 52° | 5.16 | 6.63 | 7.04 | 7.17 |
| 60° | 5.42 | 6.80 | 7.23 | 7.41 |
| 75° | 5.60 | 6.95 | 7.48 | 7.87 |
| 90° | 5.68 | 7.13 | 7.63 | 8.27 |
| 110° | 5.71 | 7.28 | 8.09 | 9.01 |
| 120° | 5.57 | 7.20 | 8.13 | 9.64 |
| 135° | 5.02 | 6.93 | 7.92 | 9.95 |
| 150° | 4.25 | 6.33 | 7.42 | 9.06 |
| Run VMG | 3.68 | 5.50 | 6.74 | 8.03 |
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 550 kg.
Rigging
A 31 rig and sail dimensions
A A 31 carries 12.00 m of mainsail hoist on a 4.07 m boom, a forestay 11.96 m above the deck and a 4.03 m bowsprit. Typical figures across the 14 boats measured under the current VPP, with the range each one spans.
Rig
Sails
The spinnaker spreads widest of all — 59 to 98 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.