Marine, Shipbuilding & Boat Manufacturing worked example

Marine Equipment Lead Time Buffer with supplier quoted lead time of 45 days: a worked example

Suppose supplier quoted lead time falls to 45 days. This page works the full calculation at that level so you can see exactly which result moves and by how much. Calculate the order buffer needed for long-lead marine equipment by comparing supplier lead time against the production schedule need date, with a safety buffer for shipping delays and inspection holds.

The inputs for this scenario

  • Supplier quoted lead time: 45 days (the input this scenario stresses; the baseline uses 90)
  • Days before need date to place order: 120 days (held at the documented default)
  • Safety buffer for delays and inspection: 21 days (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Required lead time with buffer = supplier lead time + safety buffer.
  • Protected days of supply works out to 0.02 days at these inputs, and this is the headline figure for the scenario.
  • Unprotected days works out to 0.38 days at these inputs.
  • Inventory works out to 45 pieces at these inputs.
  • Daily usage works out to 120 pieces / day at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where supplier quoted lead time sits at 90 days and the headline result is 0.04 days, this scenario comes in 50% below the baseline at 0.02 days.
  • It adds a safety buffer to the supplier's quoted lead time and compares that against how early you plan to order to reveal spare or shortfall days. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Protected days of supply: 0.02 days (headline result)
  • Unprotected days: 0.38 days
  • Inventory: 45 pieces
  • Daily usage: 120 pieces / day

Run it with your numbers

  • To rerun this with your own numbers, open the live Marine Equipment Lead Time Buffer calculator, set supplier quoted lead time to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.