IOR - NOR4711
Sailing performance analysis for a 1/2 TON ONE OFF from 1982, built by Olsen Båtbyggeri and designed by Kjærulf.
Data provided by the Offshore Racing Congress (ORC) · Certificate issued 03/06/2026
This performance sailboat offers an impressive balance with a light build for its length. It achieves 5.6 knots upwind in 10 knots of wind and can reach up to 8.6 knots in stronger winds of 20 knots. The sail plan is well-balanced with a symmetric spinnaker and a compact jib relative to the mainsail, providing solid performance across various points of sail.
Sailing performance as a polar diagram
A polar diagram shows boat speed at different wind angles and wind speeds. The distance from center represents boat speed in knots, and the angle represents the boats angle to the wind. The wind speed is shown as true wind speed (TWS), not apparent wind speed. Likewise, the wind angle is shown as true wind angle (TWA), not apparent wind angle.
Beat: Sailing upwind (toward the wind)
Beam Reach: Sailing across the wind
Run: Sailing downwind (away from the wind)
VMG Performance
Wind Speed (columns): True wind speed (TWS) in knots - the actual wind speed, not the apparent wind you feel on deck.
VMG (Velocity Made Good) is your effective speed toward your destination, not your actual boat speed.
Beat VMG (top bars): Speed made good when sailing upwind. Higher is better - it means you're reaching the windward mark faster.
Run VMG (bottom bars): Speed made good when sailing downwind. Higher is better - it means you're reaching the leeward mark faster.
Measured sails
Measurements
🏁 Race Results 🥈1
| Date | Event | Result | Class | Skipper |
|---|---|---|---|---|
| 2026 | ||||
| 25.04.2026 | Treningssamling - Løkkevika | 7/15 | Vintage | Steinar Thon |
| 2025 | ||||
| 03.05.2025 | Hvaler Rundt | 11/11 | Half Ton | Steinar THON |
| 03.05.2025 | Half Ton Class Norway - Ranking 2025 | 13/30 | Half Ton | Steinar Thon |
| 2024 | ||||
| 14.09.2024 | MK Båt Cup | 2/9🥈 | Half Ton | Stian TØNNESEN |
| 24.03.2024 | Half Ton Club - Vinterserie 2023 | 6/22 | Half Ton | Team Junior |
Race results from manage2sail.com & sailracesystem.no
Identity
Dimensions
Sail Areas
ORC Rating
Rated boat speeds
| Wind Speed (TWS) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 4 kt | 6 kt | 8 kt | 10 kt | 12 kt | 14 kt | 16 kt | 20 kt | 24 kt | |
| Beat VMG | 2.51 | 3.42 | 4.05 | 4.39 | 4.52 | 4.57 | 4.61 | 4.61 | 4.48 |
| 52° | 3.91 | 5.14 | 5.87 | 6.23 | 6.38 | 6.46 | 6.51 | 6.58 | 6.56 |
| 60° | 4.17 | 5.38 | 6.05 | 6.39 | 6.56 | 6.66 | 6.73 | 6.83 | 6.86 |
| 75° | 4.35 | 5.52 | 6.18 | 6.54 | 6.78 | 6.97 | 7.09 | 7.28 | 7.38 |
| 90° | 4.24 | 5.43 | 6.14 | 6.56 | 6.88 | 7.17 | 7.40 | 7.68 | 7.87 |
| 110° | 3.93 | 5.30 | 6.18 | 6.68 | 7.09 | 7.45 | 7.71 | 8.07 | 8.40 |
| 120° | 3.77 | 5.11 | 6.03 | 6.59 | 7.06 | 7.48 | 7.84 | 8.51 | 9.02 |
| 135° | 3.27 | 4.59 | 5.58 | 6.28 | 6.75 | 7.26 | 7.66 | 8.58 | 10.10 |
| 150° | 2.71 | 3.90 | 4.91 | 5.75 | 6.36 | 6.80 | 7.27 | 8.07 | 9.22 |
| Run VMG | 2.34 | 3.38 | 4.26 | 5.03 | 5.70 | 6.23 | 6.64 | 7.46 | 8.21 |
Boat speed (knots) at wind angle / wind speed