TT Talk - Quay crane anti-collision technology
Boom anti-collision electronic sensor technology has been readily available for use on quay cranes for a number of years. The introduction of such technology has undoubtedly been a positive development in terms of both safety and mitigating potential losses.
"Rapid improvement in reliability"
In common with all technological solutions, quay crane boom anti-collision sensing equipment has been improving rapidly to a point today where selection of an appropriate system, installed correctly can prove to be a cost effective tool in the protection of what is a major capital asset for most terminal operations.
Given the established existence of such a cost effective solution, the frequency of collision incidents around the globe is perhaps surprising. Incidents where the boom of the quay crane collides with the ship's bridge, mast or antennae, can result in claims that range from the fairly modest to multi-million dollar losses.
The types of exposure will vary on the circumstances from simple repairs to the ship and/or crane to potentially significant delays to the planned departure of the ship. Ship demurrage may be financially substantial, but reputational damage particularly if the incident involves personnel, can be more damaging. In the extreme, the collision may result in the collapse of a quay crane, extensive damage to the ship, injury or fatality of personnel and business interruption for the terminal. The quay crane is a high value asset and not easily repaired or replaced; it would not be uncommon for such equipment following a severe incident to be out of operation for several months. It is a potentially sobering thought for a port or terminal to consider how the operation would cope with the absence of one of these assets.
Since technology to prevent these types of incidents is now well-established, it may seem puzzling that all terminals have not taken the decision to protect their assets, effectively eliminating this particular exposure. Unfortunately, it seems that the perceived benefit of such a comparatively modest investment is generally only fully realised once an incident has actually been experienced.
The TT Club's latest claims analysis shows that this type of incident continues to be commonplace. Over the last five years the TT Club have received over 100 boom collision claims. All types of quayside crane are at risk, including those involved in container, bulk and general cargo operations.
The most basic form of boom anti-collision technology is a 'trip wire' system, which in the absence of an explicit request for higher specification equipment may be supplied by the manufacturer. While the trip wire system is inevitably the least expensive, there are high maintenance costs due to the need to keep tension on the wire. Further, a collision will often have occurred before the device can stop the crane. At full speed a crane may be expected take about 3.5 meters to stop and the wire will typically only be activated at around one meter from the boom. Although better than nothing, this trip wire system is far from effective and should not be considered a fail-safe.
Electronic sensors are now proven to be effective and can provide warning, slow down and stop signals to prevent this type of incident entirely. TT Club recommends that such sensors are retrospectively installed to all existing quay cranes and explicitly specified for all new quay cranes. A laser sensor system from supplier Sick Sensor Technologies (www.sick.com
) is widely considered as the most proven and cost effective system; this is supported by the TT Club's experts and experience. The latest sensors are simple to install and require minimum maintenance. For a cost in the region of US$15,000 per crane including installation, this is a very worthwhile investment.
"The equipment must be installed and commissioned by a competent person"
However, the sensors must be installed and commissioned by a competent person. The TT Club has identified several situations where such sensors were installed and/or commissioned incorrectly,which have given rise to false alarms and nuisance operational interruptions, thus providing an unreliable experience. Where correctly installed and commissioned in our experience the equipment is in fact effective and reliable.
In one example a terminal had the sensors installed on the crane front legs looking out along each side of the boom. As a result, when the boom was raised to travel over the ship's bridge, the boom anti-collision needed to be disabled. Almost inevitably, a collision occurred on the occasion that the boom was not raised fully; incorrect installation and commissioning was the root cause. It is understood that Sick Sensor Technologies has taken positive steps to improve their installation and commissioning instructions, as well as establishing a global network of approved and competent installation contractors. The TT Club welcomes this initiative since incorrect implementations have only occurred where non-specialists have been involved at the point of manufacture or retro-fitting.
In summary, the effective selection and installation of proven electronic sensor devices to all quay crane booms, mitigating the not-unlikely risk of accidentally colliding with ships' superstructures, could save the port industry millions of dollars of damage and operational downtime.
We hope that you have found the above interesting. If you would like further information, or have any comments, please email us, or take this opportunity to forward to any colleagues who you may feel would be interested.
We look forward to hearing from you.
Risk Management Director, TT Club