プロペラピッチ・スリップ計算機 ⚙️
プロペラスリップ率とキャビテーションリスクを計算。ピッチ、直径、RPM、ギア比を入力して推進効率を分析。
プロペラピッチ・スリップ計算機の使い方
プロペラピッチ（インチ）、直径、エンジンRPM、ギア比、GPS実速度を入力します。
5–15%のスリップが娯楽船の正常範囲です。25%超は船底の汚損や損傷が疑われます。
キャビテーションリスクはチップ速度（π×直径×シャフトRPM/12）で判定。9,000 ft/min未満が安全です。
FAQ
What is propeller slip and how is it calculated?
Propeller slip is the difference between theoretical speed (pitch × RPM / gear ratio / 1215.2) and actual GPS speed. Slip % = (theoretical − actual) / theoretical × 100. Normal recreational boats run 5–15% slip.
What causes high propeller slip?
High slip (> 25%) is caused by hull fouling, propeller damage, incorrect pitch for load, or heavy displacement. Clean hull regularly, inspect prop blades for nicks, and consider re-pitching.
What is cavitation and how does tip speed affect it?
Cavitation occurs when propeller tip speed creates low-pressure bubbles that implode on the blade surface, causing damage and loss of thrust. Tip speed = π × diameter × shaft RPM / 12. Below 9,000 ft/min is safe; above 14,000 ft/min is critical.
What is the ideal propeller slip for recreational boats?
5–15% slip is ideal for most recreational planing boats. Displacement hulls typically run 10–20%. Racing props can achieve 3–8%. Slip outside these ranges warrants inspection.