One of ICON’s flagship projects — replacing the cranes on an offshore platform — has officially moved from design and fabrication into the installation phase, marked by a significant oversize load transport job: getting a brand-new 16m long boom rest structure from Henderson to Karratha, a journey of over 1,500km.
A load that tested the limits of what can move by road
At 6.8m wide and just under 6m high, the boom rest structure sat well outside standard road dimensions, putting it squarely into oversize/overmass (OSOM) territory under Western Australian transport regulations. Under Main Roads WA rules, any OSOM load wider than 5.5m or longer than 40m requires a Traffic Escort Warden in addition to a standard pilot vehicle — a requirement this load’s 6.8m width triggered outright. Loads at this scale typically require route surveys, escort vehicles, and coordination with multiple road authorities and utility providers before a single wheel turns.
The original plan was to move the structure by sea freight. Working with Polaris Engineering and transport partner Sienalex Transport, ICON pivoted to road transport instead — a decision that delivered both a faster delivery timeline and significant cost savings for the client. Sea freight can be the more straightforward option for large, awkward loads, but it comes with its own schedule risk: port congestion, vessel availability, and handling at both ends can all add delay that’s hard to plan around. Road transport keeps the load under the project’s direct control for the entire journey, at the cost of taking on the complexity of an oversize road permit and route survey instead.
Navigating the practical challenges of oversize load transport
Getting a load of this size across more than 1,500km of Western Australian highway wasn’t simple. It required early engagement with Western Power to lift multiple high-voltage lines along the route, clearing the way for the oversize convoy to pass safely. On top of that, the team had to navigate the layers of transport regulation that apply to any oversize or overmass vehicle movement in WA, including permits and route approvals from Main Roads WA.
None of this happens without solid planning and close coordination between engineering, logistics and transport partners. That planning is what turned a genuinely difficult logistics challenge into a delivery that beat the original sea freight timeline — proof that the less visible parts of a project can be just as decisive as the engineering itself.
Part of a bigger platform upgrade
The boom rest structure is one component within a larger offshore platform crane replacement project, with this oversize load transport job marking a visible milestone in that broader program moving from fabrication into installation. It’s a good example of how the unglamorous logistics side of a project — getting a fabricated component from a workshop to site — can be just as technically demanding as the engineering that produced it, and just as capable of derailing a schedule if it isn’t planned properly.
The Henderson-to-Karratha route itself says a lot about how WA’s offshore industry is structured. Henderson, on Perth’s southern coast, is home to much of the state’s heavy fabrication and marine industry, while Karratha in the Pilbara serves as the logistics base for North West Shelf offshore oil and gas operations. Moving large fabricated components between the two is a routine, if never simple, part of getting offshore equipment from workshop to platform.
To find out more about how ICON manages transport and installation engineering on projects like this, see our Transport & Installation Engineering capability page, or read more about the oversize and overmass permit system on Main Roads WA’s website.
