King 40
King Marine · Mark Mills · 2008
Updated
The King 40 is a 12.12 m displacement racing yacht designed by Mark Mills and built by King Marine, first launched in 2008. It races in Class B. Across the measured fleet it goes better than its own numbers promise, ahead of 90% of the designs it races against. It is at its best in light air and struggles to hold that once it blows.
Goes better than its own measurements promise, and does it better than 90% of the boats it races against.
10th of 92 in its class.
Updated — First Race Edge for this design. Enough boats of this design have now been measured to rank it. It is strongest in light air.
This design has been found in real race results — 39 starts across 7 events — not only in measurement files.
Length
12.12 m
39′ 9″
Beam
3.70 m
Draft
2.50 m
Displacement
7.1 t
Sail area
97 m²
On the podium
Where a King 40 finishes when she goes racing.
On the podium
21%
of 39 starts by 3 boats
Wins
8%
Read from 39 starts by 3 boats between 2015 and 2026, counting races with six boats or more.
Recent regattas
The latest events where a King 40 was on the start line, named as the organisers publish them.
Marstrand Big Boat Race2026
Pittwater Regatta - NSW ORC Championship2025- Pittwater Regatta - NSW ORC Championship2024
ORCi European Championship2022- Norgesmesterskap ORCi2019
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
19%
of these races end on the podium
Offshore & coastal
—
Not enough data yet: 5 races over 10 NM carry a published distance.
Who she races against
The designs a King 40 actually lines up with, most often first. The bar shows how those meetings ended.
Also met, too few times for a figure:
Mylius 50 (6 meetings), Melges 32 (6 meetings), 1d35 (6 meetings), Bavaria Match 38 (6 meetings), XR 41 (6 meetings), X-99 (6 meetings), Bavaria Match 42 (6 meetings), TP 52 (Farr) (6 meetings), J/109 (6 meetings), Bavaria Match 35 (6 meetings), X-34 (6 meetings), Mumm 36 (6 meetings), First 35 (Farr) (5 meetings), Seaquest 36 (3 meetings), J/122 (1 meeting), HH 42 (1 meeting), Swan 48 (Frers) (1 meeting), First 45 (Briand) (1 meeting), Swan 56 (1 meeting), Grand Soleil 42 (Carkeek) (1 meeting), ILC 40 (1 meeting), Arcona 430 (1 meeting), J/46 (1 meeting), Sly 42 (1 meeting), Pogo 10.50 (1 meeting)
Some of the boats it races against
How the King 40 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
5.90
37°
Beam reach
9.16
90°
Broad reach
11.26
135°
Downwind VMG
8.63
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.
There is no obvious weak spot here. It rewards preparation and crew work more than it rewards picking the right day.
Where it gains
Its best ground is off the wind when it blows, where it does more than its size and sail area promise, and by a margin worth having. It holds that advantage on the run as well, so the gain is not down to one leg of the course.
Where it pays
It falls short on the beam when it blows, 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 0.8 kn either way.
At 10 knots this design makes back more than its rating asks on the downwind.
How fast is a King 40
Boat speed in knots, by true wind angle and wind strength.
| Angle | 6 kn | 10 kn | 14 kn | 20 kn |
|---|---|---|---|---|
| Beat VMG | 3.93 | 5.31 | 5.72 | 5.90 |
| 52° | 5.97 | 7.54 | 7.91 | 8.09 |
| 60° | 6.29 | 7.71 | 8.10 | 8.32 |
| 75° | 6.50 | 7.84 | 8.37 | 8.73 |
| 90° | 6.50 | 7.98 | 8.52 | 9.16 |
| 110° | 6.62 | 8.23 | 8.91 | 9.82 |
| 120° | 6.52 | 8.22 | 9.15 | 10.37 |
| 135° | 5.85 | 7.93 | 8.98 | 11.26 |
| 150° | 4.92 | 7.21 | 8.34 | 9.96 |
| Run VMG | 4.25 | 6.25 | 7.31 | 8.63 |
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 830 kg.
Rigging
King 40 rig and sail dimensions
A King 40 carries 16.00 m of mainsail hoist on a 5.55 m boom, a forestay 16.21 m above the deck and a 6.46 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 — 152 to 184 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.