Onshore industrial modules are now being transported in a revolutionary way. One new approach incorporates the use of the floating super pallet (FSP), a flexible intermediate transport solution consisting of ballastable pontoons specifically developed for industrial modules.

Technological advancements have paved the way for complex and progressive logistics management, which is being applied to the transportation of onshore industrial modules using the FSP, a standard unit piggy-backed onboard semisubmersible heavy transport vessels (HTVs)—unit carriers. This approach offers a credible and proven alternative to conventional methods of module transport.

The modular transport challenge

Downstream modular transport methods can be inflexible and costly. Project managers responsible for ensuring timely transports of multiple modules often experience schedule uncertainty. Projects that transport modules from multiple fabrication sites are additionally complex and require the maximum flexibility in their module logistics. All these elements create complex logistics scenarios that may be subject to delays.

In addition, the use of HTVs can be far from optimal, often resulting in HTVs lying idle. In the conventional approach, an HTV arrives at the fabrication yard to begin the loading operation. This phase of the transport is most often inefficient. While the HTV is idle at the quayside, a peak in man-hours occurs during the execution of the loading operation. The same can be observed at the receiving location. These are two phases of the transport with potential to optimize the schedule, resulting in significant financial and time gains.

Next to schedule optimization challenges, onshore industrial plants are increasingly being constructed at remote locations and restricted by shallow water along with stringent environmental and quarantine requirements. Shallow-water environments can limit and even exclude HTVs from loading or discharging cargo. Materials offloading facilities (MOFs) must be developed to receive HTVs’ increasing project costs and complexity.

LNG industry stands to benefit

In the new approach, FSPs significantly reduce inefficiencies in resource utilization. In the Dockwise concept the vessel is mobilized when modules are already loaded on FSPs. In conjunction with the HTV, multiple FSP sets are in rotation to transport large numbers of modules. While one set is en route to the destination, the other two or more sets are made available for the loading and discharging operations at both ends.

This “drop-off-and-go” rotation system minimizes the turnaround time of vessels and largely reduces waiting queue problems along with port congestion. Vessel utilization is increased by about 40%, leading to cost efficiency and lower overall investment. The costly man-hour peak activity is flattened, resulting in financial gains. Furthermore, the FSP can be used as floating storage at the loading and discharge location.

Most importantly, the FSPs provide project managers with reliable, predictable and cost-effective executions along with the peace of mind that comes with complete schedule flexibility.

Environmental case study

LNG facilities are being constructed in even more remote locations to support the increasing energy demand. These locations are often located in pristine environments and are subject to stringent environmental and quarantine requirements. Some of these locations restrict HTVs altogether as they pose a serious threat due to the introduction of invasive species via a vessel’s ballasting operation where water containing nonnative species can be pumped out of the tanks to submerge the HTV, which then allows the cargo to be floated or rolled off the vessel.

Invasive species are a serious concern for local authorities where biodiversity is at risk. For this reason, the company invested in technology to mitigate the introduction of invasive species throughout the world. HTVs can bypass the strict quarantine by using FSPs. At the loading site, the FSP is floated on the HTV. Once secured on deck, the ballastable tanks of the FSP can be either emptied at the loading site or treated during transit. This ensures invasive species are not introduced at the receiving site.

Upon arrival, the HTV submerges outside the strict quarantine zone and floats off the FSPs, which are then towed into the strict quarantine zone to the discharge location. Next to invasive species, there are other environmental concerns at hand when dealing with modular logistics to remote locations.

Factoring in environmental best practices in logistical management is increasingly important. The HTVs are now used more efficiently, resulting in less waiting time or lying idle, which subsequently results in reduced fuel consumption and lower emissions to air.

FSPs inherently contribute to sustainability by helping companies reduce their environmental footprint. FSPs have minimal MOF requirements, thus decreasing environmental impact. This can be of particular interest when building in an environmentally sensitive area or remote location. FSPs allows for easier environmental or quarantine compliance. Remote locations restricted by shallow waters can be reached without the need for the construction of new roads. In addition, estuarial sites are accessible without major modifications. In essence, the FSP solution offers LNG projects an alternative logistics solution with potential to reduce their footprint.

In a recent safely executed project, the client specifically awarded the company with the logistical management of industrial modules to a remote industrial site with environmental restrictions. Because of the requirement to minimize the environmental impact, Dockwise delivered a solution that was both environmentally and financially interesting.

“For this particular project, the FSP was the only solution for getting our client’s modules on site,” said Marco Tanis, project manager at Dockwise. The site had neither a harbor nor offload facility close by. Furthermore, transporting the modules on land via a big port was not possible. “Building an onsite offloading facility was out of the question due to the environmental impact on the coral reef and native species,” Tanis said.

Next to the environmental constraints, the site was located in shallow water in tidal conditions, which made it impossible for HTVs to offload the modules. The only way to reach the site with the modules was with the combination of HTV and FSPs, whereby the HTV arrived near site and floated off the FSPs, which were then towed by tugs to shore and grounded in place for modules to be rolled in with self-propelled modular transporters.

The technical side

During a high tide window, the FSP can be towed above the prepared beach area using tugs. The FSP will settle down on the beaching area during low tide, and the sea fastening can be removed. The FSP is equipped with bottom valves, so the water level in the tanks rises with the tide level outside to avoid uprising during the loading or discharging operation. Prior to the FSP being refloated, the water is released from the ballast tanks during low tide.

Several water ballast tanks, pumps and seawater chests give the FSP a flexible solution to have the vessel loaded and unloaded while floating or aground (roll-on/roll-off). The cargo is loaded or discharged via ballasting. All tanks are ballasted and deballasted by a combination of a passive ballast system using the bottom valves and an active ballast system consisting of portable submersible pumps.

The maximum single pump capacity is approximately 750 cu. m/hr (26,486 cf/hr). Tanks can be simultaneously emptied or filled within two hours. If needed, all tanks can be cleaned after ballast operation and will drain completely empty by opening bottom drain plugs of all individual tanks while in transit on the HTV.

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