Construction
Bridge repairs and maintenance
With our work platforms installed under bridges and wharves, our tradespeople provide repairs and maintenance services including concrete repair, electrical and plumbing upgrades, timber replacements and rock piling.
Floating solutions
We supply and install floating, modular jetties in a range of environments. Boab Commercial Marine’s floating jetty applications range from large marinas (to accommodate tidal movement) through to hydroelectric dams (where water releases to create electricity). We provide solutions for every situation.
Most marine construction work needs two suppliers: one for the platform and one for the trade. Boab can supply both. We can install the work platform and crew the vessels around it. Plus, our own tradespeople can carry out the repairs from it. One contract, one site induction, one point of accountability when the tide turns.
What does marine construction support cover?
Marine construction support is the on-water side of a civil project: the platforms the work happens from, the vessels that move plant and people, and the barriers that keep the waterway compliant while it runs.
It gets engaged on bridge replacements and refurbishments, wharf and jetty works, dam and hydroelectric infrastructure, outfall and intake construction, shoreline protection, pontoon and marina installation, and remediation of ageing water-access structures.
Choosing a work platform
The platform decision sets the cost and the program of a marine construction job more than any other choice. There are three broad options, and they are not interchangeable.
The right answer usually depends on the water rather than the work. Tidal range, current, depth at low water and what the bed is made of decide whether a floating platform will hold position, and that is worth establishing before a methodology is written rather than after. A bathymetric survey of the work area costs a fraction of discovering it during mobilisation.
| Platform type | Suits | Watch for |
|---|---|---|
| Suspended or under-bridge platform | Soffit and pier repairs, concrete and timber work, services upgrades where the deck above is live | Access and rigging, headroom and clearance above the water line |
| Floating modular barge | Plant-based work beside a structure, piling support, material handling, jetty installation | Deck load capacity, mooring and anchoring in current, movement with tide |
| Fixed or spudded platform | Work that needs a still deck with no movement at all | Bed conditions, water depth range, set-up and relocation time |
Planning the work around the water
Sediment and debris control usually runs alongside the build, and we supply and install silt curtains and log booms as part of the same package, so the containment and the construction work off one anchoring plan and one crew.
The thing that separates marine construction from land construction is that half the variables are not yours to control. Four of them decide the program:
Tidal range and current. They set the working windows, the anchoring and whether the plant can be positioned at all on a given day.
Water level changes in dams Drawdown and refill move the work face vertically, sometimes by metres, over the length of a program.
Weather windows. Lost days come in whole units. A crew on a wharf is a full day of labour, plant and program.
Approval conditions. Turbidity limits, exclusion zones and noise restrictions shape the method before the first pile goes in.
Vessels and plant
Marine construction work runs off deck space, lifting capacity and the ability to hold position.
- Modular barges give a configurable work platform that can be sized to the job and moved by road, and fitted with cranes, winches, generators and anchoring systems.
- Aquatruck, a 7.5 metre HDPE workboat, handles material transport, positioning and general site support.
- Crooked, a 9.1 metre tri-hull cleared for 2C operations, covers open and coastal sites.
- Shallow river, creek and dam margins are reached with punts such as Little Mate.
Compliance, crew and trades
Every Boab vessel is maintained to commercial survey standard and complies with the National Standard for Commercial Vessels under the Australian Maritime Safety Authority (AMSA). Our skippers hold current AMSA Certificates of Competency for the vessel and operational area. Documentation can be supplied for your induction and safety management system before mobilisation.
Our people come from marine, construction and government backgrounds, which matters on a tier one site. They work inside a principal contractor’s safety system, complete site inductions, contribute to JSAs and understand why a stop-work happens.
Where we work
Boab Commercial Marine operates Australia-wide from our base at Oak Flats, New South Wales. Because the fleet is road-transportable, we reach inland dams, alpine storages and remote river systems that coastal-only operators cannot. We work regularly across Sydney and NSW waterways, the Shoalhaven and Illawarra, the Snowy Mountains and ACT, and into Queensland, Victoria, South Australia, Western Australia, Tasmania and the Northern Territory.
Frequently asked questions (FAQs)
Do you supply the platform only, or carry out the works as well?
Either. Boab hires out barges, punts and workboats with skippers to contractors running their own trades. We also repair work ourselves. Our tradespeople handle concrete repair, electrical and plumbing upgrades, timber replacement and rock piling from platforms installed under bridges and wharves. Most clients take the combined option because it removes the coordination gap between the platform arriving and the work starting.
Can your barge take our excavator, crane or piling rig?
Modular barges are configured to the load, so the answer depends on the weight, footprint and how the plant will operate once aboard. Send us the machine model, operating weight and what it will be lifting, and we will confirm the configuration. Rated capacity, not deck area, is the limit that matters.
How does the plant get on and off the barge?
The loading method is worked out per site and depends on the bank, ramp access and tidal range. Options include ramp loading from a hardstand, crane transfer, or assembling the platform alongside. Getting plant off at the end is planned at the same time, since a falling water level can turn a simple exit into a two-day problem.
Can you work under a bridge with limited headroom?
Yes. Under-bridge platform work is a core part of what we do, and low clearance is normal rather than unusual. Available headroom changes with water level, so clearance is assessed at the highest water in the program, not on the day of the site visit.
Do you work in dams where the water level changes during the project?
Yes. Cotter Dam and the Snowy Hydro projects all involve water level movement across a program. Drawdown and refill are planned into the methodology, including how the platform is re-positioned, how access is maintained and what happens to moorings as the level moves.
Are floating jetties permanent or temporary?
Both. We install temporary floating access for the length of a construction program and remove it afterwards, and we supply permanent modular jetties for marinas, dams and public infrastructure. The mooring design differs substantially between the two, so it is worth deciding early which one you need.
Who handles environmental approvals and sediment control?
Approvals are usually held by the principal contractor or their environmental consultant. We deliver the physical controls those approvals require, including supply, installation and management of silt curtains, log booms and floating containment booms, and we keep the inspection records that get asked for at the compliance review.
Can you work on live sites with traffic overhead or vessels passing?
Yes. Bridge works usually continue with traffic running above and marine traffic passing alongside. Exclusion zones, notifications to waterway authorities and traffic timing are built into the plan before mobilisation, and our skippers are experienced holding position in working channels.
How far ahead should we book for a long program?
Longer-term hires and multi-stage programs are worth locking in as early as possible, particularly where a specific barge configuration or a remote mobilisation is involved. Short-notice work is often achievable. Call 1300 00 2622 with your dates and scope, and we will tell you what is available.
Construction projects
Some of the construction projects our commercial boats and skippers have undertaken…
