Zephyr - NOR9825
Sailing performance analysis for a ELVSTRØM 10,5 from 1984, built by and designed by Elvstrøm/Kjærulf.
Data provided by the Offshore Racing Congress (ORC) · Certificate issued 12/08/2026
The description is written by AI, but its numbers and comparisons are calculated before the text is generated.
The speed ranking comes from the ORC polar at 5 m/s and is compared with 427 Norwegian boats within ±5% of this boat's length. Upwind and downwind use VMG; reaching uses boat speed.
The scoring advantage is calculated using APH Time-on-Time against 76 Norwegian boats with similar APH from certificate year 2026. It is shown only when the advantage is clear across most of the condition range.
This is modelled performance, not a forecast. Course, waves, sails, crew, and tactics still matter.
ELVSTRØM 10,5 is faster downwind than 63 percent of comparable boats. In 10 knots of wind, it sails at 5.7 knots upwind, 7.0 knots reaching, and 5.4 knots downwind. It has an advantage on corrected scoring in 6–8 knots of wind when the course includes plenty of close-reaching.
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 🥈2
| Date | Event | Result | Class | Skipper |
|---|---|---|---|---|
| 2026 | ||||
| 22.09.2026 | Sparebanken Sør Høstcup | 5/10 | Havseilere | ODDVAR LARSEN |
| 19.09.2026 | Ågerøya rundt 2026 | 2/5🥈 | Nor Høy | ODDVAR LARSEN |
| 18.09.2026 | Høstregatta 2026 | 10/22 | Nor Rating | ODDVAR LARSEN |
| 2025 | ||||
| 20.09.2025 | Ågerøya rundt 2025 | 2/8🥈 | APH høy | ODDVAR LARSEN |
| 13.09.2025 | Bøddelen Rundt 2025 | 6/11 | Nor rating | ODDVAR LARSEN |
| 2024 | ||||
| 21.09.2024 | Ågerøya rundt 2024 | 1/7🥇 | Rating høy | ODDVAR LARSEN |
| 20.09.2024 | Høstcup 2024 VSF/CSF | 4/5 | Nor Rating Høy klasse | ODDVAR LARSEN |
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 | 2.61 | 3.64 | 4.14 | 4.37 | 4.51 | 4.61 | 4.67 | 4.71 | 4.56 |
| 52° | 4.11 | 5.49 | 6.12 | 6.37 | 6.51 | 6.60 | 6.67 | 6.73 | 6.67 |
| 60° | 4.43 | 5.77 | 6.38 | 6.60 | 6.72 | 6.81 | 6.87 | 6.94 | 6.92 |
| 75° | 4.67 | 5.99 | 6.60 | 6.84 | 6.96 | 7.06 | 7.13 | 7.23 | 7.26 |
| 90° | 4.54 | 5.94 | 6.64 | 6.96 | 7.15 | 7.27 | 7.38 | 7.54 | 7.64 |
| 110° | 4.09 | 5.71 | 6.62 | 7.00 | 7.21 | 7.37 | 7.52 | 7.79 | 8.02 |
| 120° | 3.93 | 5.53 | 6.56 | 7.04 | 7.34 | 7.58 | 7.76 | 8.08 | 8.36 |
| 135° | 3.40 | 4.91 | 6.08 | 6.82 | 7.23 | 7.60 | 7.95 | 8.67 | 9.17 |
| 150° | 2.81 | 4.06 | 5.20 | 6.20 | 6.87 | 7.26 | 7.61 | 8.45 | 9.65 |
| Run VMG | 2.43 | 3.52 | 4.50 | 5.37 | 6.13 | 6.67 | 7.07 | 7.74 | 8.55 |
Boat speed (knots) at wind angle / wind speed