Marine, Shipbuilding & Boat Manufacturing calculator

Marine Weld Labor Estimate Calculator

Estimate the total welding labor hours for a metal vessel build. Enter the total weld length from structural drawings, your average deposition rate (accounting for process and position), a joint preparation factor for fit-up and tacking, and an allowance for NDE inspection, repairs, and welder downtime. The result helps you plan welder headcount, estimate weld labor cost, and schedule structural fabrication phases.

What this calculator does

  • Estimate welding labor hours for steel or aluminum vessel construction based on total weld length, deposition rate, joint preparation factor, and inspection/rework allowance.
  • Use it when planning welding crew allocation for a metal vessel hull or structural fabrication to estimate total weld hours and cost.
  • The result estimates total welder-hours for a metal vessel fabrication project including joint prep, welding, and inspection.

Formula used

  • Base weld time = total weld length / deposition rate
  • Fabrication time including prep = base weld time x joint preparation factor
  • Total weld labor hours = fabrication time x (1 + inspection/repair allowance / 100)

Inputs explained

  • Total weld length: Sum of all weld seam lengths from structural drawings or weld map. Include hull plating seams, frame welds, bracket welds, and structural connections.
  • Average weld deposition rate: Linear meters of completed weld per arc-hour. Typical MIG on aluminum: 1.5-3.0 m/hr. FCAW on steel plate: 2.0-4.0 m/hr. Adjust for position.
  • Joint preparation and fit-up factor: Multiplier for cutting, beveling, grinding, fit-up, tacking, and repositioning. Typical: 1.5-2.5x weld time for shipbuilding.
  • Inspection, repair, and downtime allowance: Time for NDE (radiography, UT, dye pen), weld repairs, equipment maintenance, gas changes, and welder breaks. Typical: 15-30%.

How to use the result

  • Use it to staff welding crews, estimate structural fabrication cost, and schedule hull assembly phases for steel or aluminum vessels.
  • Assumes uniform weld type and position. Complex vessels with many overhead or confined-space welds should increase the preparation factor. Does not separately estimate different weld processes (MIG, TIG, FCAW).

Common questions

  • How do I estimate total weld length from structural drawings? Sum all seam lengths from plate layout drawings. For quick estimates on steel vessels, approximate weld length as 12-18 meters per tonne of steel for typical commercial hull structures.
  • Why is the joint preparation factor so high for shipbuilding? Marine welding requires precision fit-up, back-gouging on critical joints, pre-heating on thick plate, magnetic particle or dye penetrant checks between passes, and frequent repositioning of large assemblies.
  • What deposition rate should I use for aluminum vs. steel? Aluminum MIG welding: 1.5-3.0 m/hr linear (due to heat management and distortion control). Steel FCAW: 2.5-4.5 m/hr. Steel submerged arc (flat position): 5-10 m/hr for long straight seams.
  • Does this include NDE (non-destructive examination) time? Basic NDE time is in the inspection allowance. For class-surveyed vessels with high radiography requirements, increase the allowance to 30-40% or estimate NDE separately.

Last reviewed 2026-05-12.