🧮 Sailing Calculators
Five free calculators for sailboat owners — from anchor rode to boat loans. All results update instantly as you type. Bookmark this page for quick access at the dock or while planning your next passage.
Anchor Scope Calculator
Enter your anchorage conditions to get minimum, recommended, and storm-condition rode lengths.
Results based on standard scope ratios: all-chain 4:1 min / 7:1 rec / 10:1 storm; combo 5:1 / 7:1 / 10:1; all-nylon 7:1 / 10:1 / 15:1. Always verify holding in your actual anchorage. Puget Sound currents can require extra scope.
Ballast Ratio Calculator
Calculate your boat's ballast ratio and displacement/length ratio — key indicators of stability and sailing character.
Ballast ratio = ballast ÷ displacement × 100. D/L ratio = displacement(lbs) ÷ 64 ÷ (0.01 × LWL)³. Both are indicators — offshore suitability depends on many factors including hull form, righting moment, and freeboard.
Sail Area / Displacement Ratio
The SA/D ratio tells you how much "go" a boat has relative to its weight — useful for comparing designs.
Find these on SailboatData.com for your specific model.
SA/D = Sail Area ÷ (Displacement÷64)^(2/3). Uses 100% foretriangle — actual upwind performance with a 150% genoa will be higher. A boat with SA/D of 15 with a full roach main and 150% genoa can sail like an 18 SA/D boat.
Boat Loan & Total Ownership Cost
See your monthly loan payment and the full picture of what owning a sailboat actually costs per month and per year.
| Loan amount | — |
| Monthly loan payment | — |
| Monthly insurance | — |
| Monthly slip / moorage | — |
| Monthly maintenance | — |
| ▶ Total monthly cost of ownership | — |
| First-year total (add survey) | — |
| Total interest over loan term | — |
Loan payment uses standard amortization formula. Insurance estimate: 1–2% of value/year. Maintenance budget varies widely — budget 3–5% of purchase price annually for an older production boat. Haulout, bottom paint, and unexpected repairs are not included.
Bottom Paint & Haul-Out Schedule
Based on your region, paint type, and sailing frequency — get a recommended cleaning and haul-out schedule.
Schedules are guidelines — actual fouling depends on water temperature, boat movement, and paint condition. Washington State: only hard antifouling paints may be cleaned in-water; ablative paints must be hauled out to clean. See WA Hull Care Guide for full regulations.