Preview
The ORC Speed Guide, made usable
ORC predicts how fast your boat should sail with every sail, at every wind angle. It ships as a stack of polar charts you have to read by eye. Here is the same data turned into decisions you can make on the water: which sail to carry, and the speed to chase, at any wind.
Sail selection chart
The whole wardrobe on one polar. Angle around is the true wind angle, distance from the centre is the wind strength, and each colour is the sail to carry there. Turn sails on and off to redraw the map; hatched cells are changeover bands where the runner-up is within four percent. Optimum sets what the shading and trim reward: Best choice highlights where each sail most beats the rest (a headsail's upwind home), or switch to Fastest for raw boat speed. Trim to optimum then clips the weak cells so each sail collapses to the band where it is truly the sail to fly.
VPP lookup
Dial in a true wind speed and angle and read each sail's predicted boat speed, the fastest one, and the apparent wind you would feel. The matrix below gives the whole grid at once, for the winning sail or any single sail.
| TWS \ TWA | 40° | 60° | 80° | 100° | 120° | 140° | 160° |
|---|---|---|---|---|---|---|---|
| 6 kt | 5.0 | 6.3 | 6.7 | 6.5 | 6.0 | 5.2 | - |
| 8 kt | 6.0 | 7.2 | 7.4 | 7.4 | 7.2 | 6.4 | - |
| 10 kt | 6.6 | 7.5 | 7.8 | 7.9 | 7.8 | 7.3 | - |
| 12 kt | 6.8 | 7.7 | 8.1 | 8.3 | 8.3 | 7.9 | - |
| 14 kt | 6.9 | 7.8 | 8.3 | 8.6 | 8.8 | 8.3 | - |
| 16 kt | 7.0 | 7.8 | 8.5 | 8.8 | 9.3 | 8.8 | - |
| 20 kt | 7.1 | 7.9 | 8.6 | 9.3 | 10.3 | 10.0 | - |
The polar, made readable
The same VPP data ORC draws, one wind at a time. Each curve is a sail; where they cross is where you change. The diamonds are the beat and gybe VMG targets. The dashed line is the reaching headsail set flying.
Target sheet
The numbers a navigator calls, for every wind speed. Deck-ready: target boat speed and true wind angle, upwind and down, with the VMG each makes good.
| Wind | Upwind | Downwind | ||||
|---|---|---|---|---|---|---|
| TWA | Boat | VMG | TWA | Boat | VMG | |
| 6 kt | 34° | 5.0 | 4.1 | 145° | 5.0 | 4.1 |
| 8 kt | 33° | 5.8 | 4.9 | 145° | 6.1 | 5.0 |
| 10 kt | 33° | 6.2 | 5.2 | 152° | 6.7 | 5.9 |
| 12 kt | 38° | 6.7 | 5.3 | 152° | 7.4 | 6.6 |
| 14 kt | 33° | 6.4 | 5.4 | 152° | 7.9 | 7.0 |
| 16 kt | 33° | 6.5 | 5.5 | 152° | 8.4 | 7.4 |
| 20 kt | 33° | 6.6 | 5.5 | 152° | 9.3 | 8.2 |
The wardrobe
The four sails behind the curves above, with measured areas from the certificate. Every boat gets its own inventory.