Marine, Shipbuilding & Boat Manufacturing worked example

Marine Equipment Lead Time Buffer with supplier quoted lead time of 230 days: a worked example

What does the result look like when supplier quoted lead time reaches 230 days? The full calculation is worked below with real intermediate numbers. Use it when placing purchase orders for engines, generators, propellers, steering gear, or custom hardware to determine the latest safe order date.

The inputs for this scenario

  • Supplier quoted lead time: 230 days (raised for this scenario; the documented default is 90)
  • Days before need date to place order: 120 days (unchanged)
  • Safety buffer for delays and inspection: 21 days (unchanged)

Working through the calculation

  • Applying the documented formula (Required lead time with buffer = supplier lead time + safety buffer) to the inputs above produces each figure below.
  • At this operating point the engine returns 0.09 days for protected days of supply, the number this scenario is built around.
  • At this operating point the engine returns 1.92 days for unprotected days.
  • At this operating point the engine returns 230 pieces for inventory.
  • At this operating point the engine returns 120 pieces / day for daily usage.

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 156% above the baseline at 0.09 days.
  • A figure at this level is achievable when supplier quoted lead time is genuinely sustained, not just peaked for a shift. It models a single delivery against a single need date and assumes the quoted lead time is honest; it does not account for partial shipments, allocation, or supplier capacity swings.

Results at a glance

  • Protected days of supply: 0.09 days (headline result)
  • Unprotected days: 1.92 days
  • Inventory: 230 pieces
  • Daily usage: 120 pieces / day

Run it with your numbers

  • Every input above is editable in the live Marine Equipment Lead Time Buffer calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.