How do you calculate marine weld labor hours?

Divide total weld length by the deposition rate to get base arc time, multiply by the joint prep and fit-up factor, then add the inspection and repair allowance. With 450 m at 2.5 m/hr, a 2.0 prep factor, and a 25% allowance, the base arc time is 180 hr and total labor is 183.6 hr in this model's defaults.

What is a good deposition rate for shipyard welding?

Flux-cored and submerged-arc on flat plate can exceed 4-6 m/hr of effective joint completion, while out-of-position GTAW on aluminum may drop below 1 m/hr. A blended 2.5 m/hr is a reasonable yard-wide average for mixed structural steel work.

Why multiply by a fit-up factor instead of just using arc time?

Arc-on time is typically only 20-40% of a welder's shift. Tacking, fitting, grinding, repositioning, and waiting on cranes consume the rest, so a fit-up factor of 2.0 roughly doubles arc time to reflect real fabrication hours.

What inspection and repair allowance should I use?

For classed marine work with visual, MT, and some RT/UT, 15-30% is typical; high-restraint or critical joints push toward 30%+. The default here uses 25%.

Does this cover aluminum and steel equally?

Yes, but you must change the deposition rate. Aluminum GMAW often welds fast but demands more prep and lower duty cycle, so adjust both the rate and the fit-up factor rather than reusing steel numbers.

How is weld length converted to weight of consumables?

This calculator returns hours, not filler weight. For consumables, multiply weld cross-sectional area by length and wire density separately; that is a different calculation from labor estimating.

Marine, Shipbuilding & Boat Manufacturing calculator

Marine Weld Labor Estimate Calculator

A marine weld labor estimate converts raw weld length on a hull, deck, or tank into realistic billable man-hours by accounting for the fact that arc-on time is only part of the job. Estimators, fabrication shop foremen, and boatyard project managers use it to quote steel and aluminum vessel work and to load weeks of welding into a build schedule. It matters because shipyard welding is labor-dominated: getting hours wrong by even 20% blows the margin on a fixed-price hull contract. The model multiplies pure deposition time by a prep/fit-up factor and then adds an allowance for NDT, repairs, and the inevitable downtime around a slipway.

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.
It computes total weld labor hours by dividing weld length by deposition rate, scaling for joint prep and fit-up, then adding an inspection and repair allowance.

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 on the hull or structure:
Average weld deposition rate (arc speed):
Joint preparation and fit-up factor:
Inspection, repair, and downtime allowance:

How to use the result

Use it when quoting a hull, deckhouse, tank, or structural fabrication package and you need man-hours rather than just arc-time.
It assumes one blended deposition rate; mixing position welds (overhead, vertical-up) and processes (FCAW vs GTAW) will skew the estimate unless you split the run into separate calculations.

Current U.S. benchmarks

U.S. housing starts run at 1,177k per year (Census, May 2026), down 8.7% from a year earlier, the demand driver for building products.
The U.S. has 11,691 transportation equipment establishments employing about 1,682,910 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate marine weld labor hours? Divide total weld length by the deposition rate to get base arc time, multiply by the joint prep and fit-up factor, then add the inspection and repair allowance. With 450 m at 2.5 m/hr, a 2.0 prep factor, and a 25% allowance, the base arc time is 180 hr and total labor is 183.6 hr in this model's defaults.
What is a good deposition rate for shipyard welding? Flux-cored and submerged-arc on flat plate can exceed 4-6 m/hr of effective joint completion, while out-of-position GTAW on aluminum may drop below 1 m/hr. A blended 2.5 m/hr is a reasonable yard-wide average for mixed structural steel work.
Why multiply by a fit-up factor instead of just using arc time? Arc-on time is typically only 20-40% of a welder's shift. Tacking, fitting, grinding, repositioning, and waiting on cranes consume the rest, so a fit-up factor of 2.0 roughly doubles arc time to reflect real fabrication hours.
What inspection and repair allowance should I use? For classed marine work with visual, MT, and some RT/UT, 15-30% is typical; high-restraint or critical joints push toward 30%+. The default here uses 25%.
Does this cover aluminum and steel equally? Yes, but you must change the deposition rate. Aluminum GMAW often welds fast but demands more prep and lower duty cycle, so adjust both the rate and the fit-up factor rather than reusing steel numbers.

Last reviewed 2026-05-12.