Improving port operations with telescopic gangways and motion monitoring

In the past year we’ve seen a growing interest from port operators to use gangways to increase safety and improve operations both in the port and for offshore transfers near the port. For example, Port Botany recently installed a gangway tower at their bulk liquid terminal to improve berth efficiency. There is also the plan by Kimberley Ports to acquire and install gangway to give 24/7 all-tide access to cruise ships in Broome where tidal fluctuations is common.

At TENSA, two ways which we can help port operators improve are through the use of telescopic gangways to improve access at the port and the application of motion monitoring system to increase safety and reduce risks for port assets.

Improving access at the port with telescopic gangways

TENSA offers passive heave compensated, active heave compensated and uncompensated gangways ranging from 8m to 23m long. In an offshore environment, these gangways are used to allow safe offshore crew transfer such as the one used recently by Technip to transfer personnel between tug vessels and barges during the Prelude Project.

TENSA’s aluminium telescopic gangways are lightweight and easy to install, thus imposing lighter loading on the host vessel. For port operators, this means the gangways can be located either on the wharf or on a movable base.

When combined with the Active Heave Compensated Pedestal (AHCP) we developed, the gangway base can be raised or lowered. The pedestal has been designed so that it can also be active heave compensated, allowing the gangway height to be adjusted by up to 5 metres, if, for instance, a vessel needs to be accessed at a high level to accommodate transfers to a wharf in a highly tidal region. The pedestal can be set to automatically adjust height as the tide rises or falls.

Possible applications of the gangways and pedestal system in port operations include:

  • Transfer of personnel from a vessel to the wharf in locations with large tidal variations such as Broome, Darwin, etc.
  • Transferring tourists from cruise vessels to ferry vessels in locations such as Exmouth, Broome Great Barrier Reef, etc.
  • Transferring tourists from ferry vessels to wharves where there is a limited berthing facility
  • Transferring crews or personnel from tug vessels to barges in offshore operations

With the ability to be installed and removed very quickly (less than an hour), gangways need only to be on the vessel when required.

Motion monitoring to increase safety and reduce risks for port assets

TENSA’s motion monitoring system, Dynamic Motion System (DMS) which provides vessel motion and position information system can support operations at the port by providing:

  • Vessel motions (heave, heave velocity, heave acceleration, unfiltered accelerations, angular rates)
  • Attitude (heading, pitch and roll)
  • Position and GPS data (lat, long, northings, eastings, elevation, velocity)

The DMS has very powerful logging capabilities and can log from remote wireless units and local units at the same time. The DMS is available for sale or on a rental basis.

Potential applications of DMS for port operations include:

  • Measuring vessel motions both in the port and at sea
  • Determining if conditions are suitable for personnel transfer between vessels (either with or without a gangway)
  • Determining if conditions are suitable for specific marine operations – e.g. ROV launching, seabed coring , lifting operations from a vessel
  • Increasing the operating seastate windows for offshore crane operations,
  • Monitoring the performance of existing heave compensation systems.
  • Logging the position and motions of a number of vessels simultaneously

If you have upcoming port projects in need of a telescopic gangway or a motion monitoring system, contact us for a consultation.

TENSA, gangway, AHC pedestal, personnel transfer

Can high speed boats replace helicopters and carry out routine resupply?

TENSA, gangway, AHC pedestal, personnel transfer

Example concept for 40m high speed vessel fitted with TENSA AHC Pedestal and gangway providing personnel access and resupply to offshore facilities

Having to land helicopters in high winds and on heaving and rolling vessels not only poses operational but safety challenges for helicopter transfer. Helicopters are also expensive to operate and maintain, requiring a significant amount of support both on the onshore and offshore facilities.

High speed vessels offer a viable alternative to helicopters and can provide increased safety as well as significant additional functionality at a lower cost. To make this work, TENSA has developed a safe and reliable lightweight personnel transfer system suitable for installation on high speed vessels.

This complete personnel transfer solution mounts a lightweight aluminium telescopic gangway on a heave compensated platform. On the FPSO, there is a simple adjustable height landing platform. A motion monitoring system gives clear guidance on the relative vessel motions and confirmation that conditions are suitable for gangway transfer.

This is a total system that ensures that the operation can be undertaken safely.

A key feature of the gangway is active telescoping. This was developed in conjunction with Uptime in Norway and allows the gangway to be landed on a small flat landing. The end of the gangway remains in the same position by automatically telescoping in or out even if the boats move apart or together.

Vertical motion is handled by active heave compensation of the gangway support platform. The system can also be extended to compensate for relative motions between two moving vessels by using a second wireless motion reference unit on the receiving vessel. The TENSA Dynamic Motion System (DMS) already has this proven wireless connection and differential motion functionality.

With this system, the availability in a location offshore Northwest Australia would be above 90% so that all transfers could be undertaken by boat with appropriate management.

By having the ability to transport up to two 20ft containers, the system can handle virtually all of the routine and urgent supply requirements for offshore production facilities.

The whole gangway system can be secured to the vessel deck with twistlocks so that it can be easily installed and removed in under an hour. This also allows the vessel to be fully utilised for deck cargo if required.

The benefit of this system, according to Derick Markwell, TENSA’s managing director, is that “instead of having regular vessels fortnightly or monthly from the support base and one service a week with helicopter, you can have personnel transfer and up to two sea containers of cargo by boat daily”.

A single vessel could easily service three or four offshore facilities.

TENSA is looking at a system weight of under 12 tonnes, compared to a conventional active compensated gangway system that would weigh around 35 tonnes. The system costs less than 30% of the traditional systems.

“High speed vessels are most applicable at places like Exmouth where the fields are close to shore. There is also an opportunity at the limit of helicopter reach such as the northern Timor Sea. We see it is a compelling solution for the offshore oil and gas industry as it really offers benefits in all areas”.

Photo credits: Southerly and Strategic Marine