Hull Speed Extended Calculator
Advanced hull speed analysis with displacement-length ratio and performance predictions
Speed Analysis
Theoretical Hull Speed
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Maximum Practical Speed
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Displacement-Length Ratio
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Hull Classification
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Efficient Cruising Speed
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Economy Speed
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Displacement-Length Ratio Guide
| D/L Ratio | Classification | Characteristics |
|---|---|---|
| < 100 | Ultra-Light | Racing boats, can exceed hull speed |
| 100-150 | Light | Fast cruisers, good performance |
| 150-250 | Moderate | Cruiser-racers, balanced |
| 250-350 | Heavy | Traditional cruisers, seaworthy |
| > 350 | Very Heavy | Workboats, trawlers |
About Extended Hull Speed Analysis
Displacement-Length Ratio: D/L = Displacement (long tons) / (0.01 x LWL)^3. This dimensionless number indicates how heavy a boat is relative to its length.
Hull Speed vs. Maximum Speed: Lighter boats can exceed theoretical hull speed. The maximum practical speed depends on hull type, power available, and displacement ratio.
Speed Formulas: Hull Speed = 1.34 x sqrt(LWL). Semi-displacement and planing hulls use modified factors based on their ability to rise out of the water.
Note: These calculations provide estimates. Actual performance depends on hull design, sea conditions, loading, and many other factors.