Marine, Shipbuilding & Boat Manufacturing worked example

Marine Wiring Harness Length at 17% service loop and termination allowance: a worked example

What does the result look like when service loop and termination allowance reaches 17%? The full calculation is worked below with real intermediate numbers. Use it when planning wire procurement for a new boat build to estimate total cable length before detailed routing drawings are complete.

The inputs for this scenario

  • Vessel length overall (LOA): 12 m (unchanged)
  • Number of electrical circuits: 24 circuits (unchanged)
  • Average routing distance factor: 1.1 x LOA (unchanged)
  • Service loop and termination allowance: 17 % (raised for this scenario; the documented default is 15)

Working through the calculation

  • Applying the documented formula (Base cable length = vessel LOA x routing distance factor x number of circuits) to the inputs above produces each figure below.
  • At this operating point the engine returns 26,182 m for total cable harness length to order, the number this scenario is built around.
  • At this operating point the engine returns 288 m for base cable length (before service loops).
  • At this operating point the engine returns 25,894 m for service loop and termination allowance.
  • At this operating point the engine returns 1.1 % for cable utilization factor.

How this compares with the baseline

  • Against the tool's baseline example, where service loop and termination allowance sits at 15% and the headline result is 26,182 m, this scenario lands almost exactly on the baseline at 26,182 m.
  • A figure at this level is achievable when service loop and termination allowance is genuinely sustained, not just peaked for a shift. It treats every circuit as an average LOA-scaled run, so heavy-gauge battery cables and short panel jumpers within the same harness are blended together and may need separate estimates.

Results at a glance

  • Total cable harness length to order: 26,182 m (headline result)
  • Base cable length (before service loops): 288 m
  • Service loop and termination allowance: 25,894 m
  • Cable utilization factor: 1.1 %

Run it with your numbers

  • Every input above is editable in the live Marine Wiring Harness Length calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.