The cost of an unsuccessful subsea installation is rarely measured purely in dollars. It is measured in weeks of lost production, vessel day rates, ROV time and engineering rework. A small mistake at the surface becomes a large problem at depth, and the only thing you cannot do underwater is have a quiet word with the supplier.
Pre deployment fit checks against printed mock ups have become a standard de risking step in Australia's offshore work. A printed mock up at a few thousand dollars is cheap insurance against a missed install measured in millions. The workflow below is the one we run with clients planning a campaign on the North West Shelf, Browse Basin or Bass Strait.
Running a fit check programme
Lock the CAD revision. Mock up work runs against a single, signed off revision so any variances trace cleanly back to the geometry. Late changes pause the print, not the rehearsal schedule.
Choose the scale. Print 1:1 for connectors, tooling envelopes and ROV intervention pieces. Print 1:5 to 1:20 for trees, manifolds and complete structural assemblies. The scale is decided by what the rehearsal needs to validate, not by what fits the printer.
Select materials. PETG-CF and PA-CF deliver good dimensional stability across a printed assembly. ASA holds up if the mock up will live outdoors during a long rehearsal cycle. We source these from the OzFDM engineering range when batch traceability is required.
Print, inspect and document. Every mock up leaves our Perth facility with a basic dimensional inspection report, capturing as built dimensions against design intent. That report becomes part of the installation engineering pack.
Run the rehearsal. Fit checks against host hardware, ROV access trials, lifting and handling rehearsals, and where relevant camera familiarity for the ROV pilots. Capture variances against the CAD revision in writing.
Feed findings back. Variances drive CAD or installation procedure changes before steel and titanium gets cut. The next revision goes through the same loop, with fewer surprises each time.
Surface finish tip
For ROV camera familiarity, paint mock ups in operational service colours. For engineering fit checks, a clean printed finish is usually enough. Decide early so the airbrushing team can plan around it.
What gets mocked up
The common requests are subsea connector envelopes verifying the actual connector and its surround clear adjacent hardware, tooling envelopes for ROV intervention tools verifying access angles and reach, structural connection points confirming alignment features mate as designed, and complete component assemblies for transport and handling rehearsals. Each category has its own scale, material and finish choice, but the workflow above stays the same.
Documentation discipline becomes critical for audit. Inspectors want to see which CAD revision was printed, what tolerances were achieved, what variances were noted, and what installation considerations emerged. A defensible record of pre deployment verification protects the project when something later goes sideways at depth.
We also see fit check work used to validate transport and logistics plans, particularly for oversized assemblies moving on flatbed or roll on roll off from a quayside fabrication yard to the supply vessel. A clear 1:10 mock up answers more lashing and clearance questions in an hour than a week of email.