Tool
Voyage provisions estimator
Estimate the storage burden created by crew size, voyage duration and selected daily food and water allowances. The tool illustrates scale rather than prescribing a historical ration.
Enter the crew size and voyage assumptions to see the total quantities carried.
What the estimator shows
The calculation multiplies people by days and by the selected daily allowance. That makes the relationship between voyage length and storage immediately visible. If twenty people each receive three litres of water per day for fourteen days, the vessel needs 840 litres before allowing for leakage, contamination, cooking, washing or reserve capacity.
The result should not be read as a recommended ration. Historical requirements differed with climate, diet, workload, vessel type and access to resupply. The purpose is to show why long-distance voyaging demanded serious storage planning.
Why historical provisioning is difficult to model
Historical sources sometimes record formal ration scales, but actual practice could differ. Food might spoil, casks might leak and crews could be placed on reduced allowances after delays. Merchant shipping and naval administration also worked under different commercial and institutional pressures.
For that reason, the estimator lets visitors choose the assumptions instead of presenting one historical number as universal. The related guide on food, water and provisions at sea explains the wider context.