Given their exposed positioning, the risk of the boom of a quay crane colliding with a ship is perennial. The introduction of boom anti-collision electronic sensors for use on quay cranes has undoubtedly mitigated this operational risk. For a variety of reasons however, this type of loss continues to occur far too regularly.

Boom collisions cost

Crane boom collisions with ship superstructures vary from minor impacts with the bridge to, in one instance, an incident which caused around US$2 million worth of damage to the crane itself. Damage to the ship can also result in costly repairs and delays. However, with a crane out of service for six months it is typically not only the obvious damage and repairs of concern, but the business interruption impact. In the event of a total loss, the operation could be without a replacement crane for a significant period of up to 24 months, depending upon the lead times from the manufacturer. How would this affect your operation?

The operation could be without a replacement crane for a significant period of up to 24 months

TT Club’s latest analysis of claims shows that this sort of accident continues to be common. During the last five years (2019-2023) TT handled 95 claims where the quay crane boom collided with the ship, with an insured cost of over US$9 million. It should not be underestimated that many associated costs, such as reputational damage and management time handling the disruptions, inevitably are incurred in addition to any insured costs.

73% of the claims involved incidents when the boom hit the ship while traversing the accommodation/bridge area, including the mast and radar. 27% of the reported claims noted the boom striking a ship’s crane. In one of the recorded claims the quay crane had a boom anti-collision system installed, but it had been deliberately overridden by the operator. All other claims could have been avoided by having a boom anti-collision system installed and operational.

Unfortunately, one incident occurred where the quay crane hit a ship’s crane and subsequently collapsed onto a stevedore resulting in a fatality.

While more robust training for crane drivers, particularly utilising simulators is recommended, it is recognised that operational mistakes can occur. Given the value and operational importance of quay cranes, the installation of a suitable boom anti-collision system should be considered a minimum standard.

Electronic sensors work

Technology to prevent this type of incident has been well-established and promoted by TT Club for many years. It may seem puzzling that terminal operators have not universally protected their assets and eliminated this liability exposure. Unfortunately, the reasoning may only become compelling after an operator has experienced a collision.

The most common form of boom anti-collision is a trip wire system. These devices are typically supplied by the manufacturers when the specification asks generically for boom anti-collision. They are the least expensive system of their type, but require regular maintenance since it is necessary to keep tension on the wire. Further, the device may be ineffective in fully preventing a collision. At full speed a crane will typically take about 3.5 metres to stop completely, while the wire is only activated about one metre from the boom. Although better than nothing, such trip wire systems are far from effective and definitely not a fail-safe. They provide collision detection, not avoidance.

Trip wire systems are far from effective and definitely not a fail-safe

Electronic sensors are now proven to be effective and can provide warning, slow down and stop signals to eliminate this type of incident. Latest sensors are effective in most weather conditions. It is recommended that they be retro-fitted to all existing cranes and specified for all new cranes. A laser sensor system from Sick Sensor Technologies is considered by many in the industry as the most proven and cost effective system; this is supported by TT’s experts and experience. The latest sensors are simple to install and require minimal maintenance. There are a number of companies that can supply or provide advice on complete boom anti-collision electronic sensor systems, including Lase, Arc, Kone, Siemens, ABB. For a cost in the region of US$30,000 per crane, including installation, this is likely to be a very worthwhile investment.

Due diligence

While operationally effective, the sensors must be installed and commissioned by a competent engineer. TT has identified a number of occasions where the sensors were installed and/or commissioned incorrectly. Crane manufacturers, terminals and/or a contracted third-party have been found to be at fault.

In one instance, the terminal was taking steps to remove all of their boom anti-collision sensors because of nuisance ‘trips’. The crane booms faced due east and the sensors gave false trips at 10am each morning due to the angle of the sun. A third-party had installed the sensors and was not aware that there was a commissioning set-up to prevent this problem. The correct set-up was implemented and the system subsequently worked reliably. Another terminal had the sensors installed on the crane front legs looking out along each side of the boom. When the boom was raised to travel over the ship’s bridge the boom anti-collision needed to be disabled. One day when this was done, the boom was not raised fully and hit the ship; again, incorrect installation and commissioning was to blame. Terminal operators should not allow the systems once installed to be by-passed or disabled, and engage with workforce and engineers when issues are identified.

In summary, fitting proven electronic sensor devices to all quay crane booms to prevent them colliding with ships could save the port industry millions of dollars of damage and operational downtime each year. Nevertheless, operators should not overlook the importance of having such solutions installed by a competent engineer.

Operators should not overlook the importance of having such solutions installed by a competent engineer.

-

If you would like further information, or have any comments, please email us, or take this opportunity to forward to any others who you may feel would be interested.