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Precision Rock Dumping


Subcon have extensive experience in the dumping of aggregate subsea on pipeline assets using bulk bags with subsea deployment frame for stabilization, scour-mitigation and freespan correction.

Dumping aggregate from the crane hook using bags with built in chutes can be inaccurate due to vessel motions and movement of the crane wire. Similarly dumping from a grab or bucket presents the same issues and is limited to shallow water applications.

Subcon’s precision rock dumping solution reduces project cost by removing the need for a dedicated rock dump vessel. Aggregate is lowered to the seabed in bulk-bags, where the bottom can be opening in case of bottom-opening bags, of the bulk bags are tipped over in the case of larger quantities allowing precise placement of aggregate.

Subcon’s rock dumping solutions combined with concrete mattresses can provided robust stabilization and protection measures, able to withstand severe environmental conditions.


The bottom opening bag provides highly accurate deployement of rock at the target location, compared to a conventional bulk bag.

It is installed faster and lowers the risk of the operations as the ROV is not used to cut the bag.

Subcon provides an engineered custom built lift frame that deployed multiple bags in a single lift saving offshore installation time.

Subcon can provide a turnkey stabilisation solution for the client tailored specifically for the asset.

Alternatively, Subcon can provide bags and lift frame for deployment from client vessel.

Subcon has a standard size but can design and fabricate any bespoke solution.

Subcon owns the fabric manufacturing facility and therefore has complete control over quality and schedule requirements for bespoke solutions.

All Subcon bags are designed in accordance with DNV 2.71 and suitable for offshore lifting.

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