Mooring Line Load Calculator
Calculate wind and current loads on moored vessels and size dock lines appropriately
Load Analysis
Total Wind Load
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Total Current Load
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Combined Maximum Load
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Load per Line (Working)
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Required Line Strength
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Recommended Line Diameter
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Windage Area (Lateral)
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Underwater Area
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Nylon Dock Line Reference
| Diameter | Breaking Strength | Working Load (15%) |
|---|---|---|
| 3/8" | 4,400 lbs | 660 lbs |
| 1/2" | 7,500 lbs | 1,125 lbs |
| 5/8" | 12,400 lbs | 1,860 lbs |
| 3/4" | 17,000 lbs | 2,550 lbs |
| 1" | 29,800 lbs | 4,470 lbs |
Dock Line Guidelines
Line Length Recommendations
Bow & Stern Lines: 2/3 of boat length minimum.
Spring Lines: Equal to or greater than boat length.
Breast Lines: Just long enough to reach cleats with some slack.
Material Selection
Nylon (3-strand): Best shock absorption, standard choice for dock lines.
Nylon (double braid): Less stretch, better for spring lines.
Polypropylene: Floats but weak - not recommended for dock lines.