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Alfredo Contaldovideo
November 19, 2025 · 33 min · 2K views
What this video covers
Two fuel-calculation exercises from the Italian offshore boating licence exam (patente nautica oltre 12 miglia) are worked through on nautical chart 5D, sector B, using the 45-90 polar bearing method.▶ 5:39 The first exercise departs from Castiglione della Pescaia on a compass heading of 271°, with a magnetic variation of 1° west giving a true heading of 270°.▶ 5:57 Two polar bearings on Scoglio dello Sparviero, taken 22 minutes apart at 6 knots, fix position A. The route then continues to a GPS waypoint at 42°50'N, 10°37'E.▶ 11:07 Total distance measures 13.6 nautical miles; at 6 knots that gives 2.2 hours.▶ 16:13 Multiplying by the 10 L/hr fuel consumption and by 1.3 for the 30% reserve yields 28.6 litres.▶ 17:50 The second exercise starts from coordinates 42°38.8'N, 10°58.5'E on a compass heading of 305° (true: 302°).▶ 19:09 Speed is unknown and must be derived: the 45-90 fix on Scoglio dello Sparviero shows 1.5 nautical miles covered in 17 minutes, giving 5.3 knots.▶ 28:53 Total distance to the fix is 14.7 nautical miles, travel time 2.7 hours, and at 5 L/hr with the 1.3 reserve multiplier the required fuel is 17.5 litres.▶ 29:52 The core formula throughout is: fuel = hourly consumption × time × 1.3.▶ 32:38
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