New OCIMF publication on Ship Security – Bridge Vulnerability Study
OCIMF has recenlty published an Information Paper on Bridge Vulnerability, a detailed scientific study which offers both short and long term suggestions for preventing injury to staff during an attack.
OCIMF engaged a multinational defence technology company, QinetiQ, to conduct atwo-phased study using computer software simulations to investigate the vulnerabilityof the bridge of a selection of tanker tonnages (from 30,000dwt to 300,00dwt) whencoming under fire from an attack.
The aim of the study was to determine the likelihood of injury to, and the physicalvulnerability of, seafarers on the bridge of a vessel when the vessel was subjected toattack by small arms weaponry. Simulations were carried out in order to determine the:
- Effects of firing a variety of weapons from numerous positions both in terms of rangefrom the vessel and angle off the bow
- Likely penetration into the bridge
- Likely secondary fragmentation resulting from the shattering of windows
Based on the results of this study a package of protective measures are recommended.
Ensure that bridge windows do not shatter upon impact causing secondaryfragmentation. Check that the glass is either laminated to a minimum Standard,(EN 1063 BR6 or its equivalent as discussed in the Annex to this Paper), or that ashatterproof film is attached to reduce the likelihood of glass fragments, this beingof a comparable Standard. While noting that the study simulations only modelledfragmentation from glass (rather than other lining materials found on a bridgeof a ship) ensuring that bridge windows do not shatter upon impact is the mostimportant single measure found to limit injuries to bridge crew.
Fit RPG protection to the bridge wings, either using proprietary net technology ora double chain link fencing arrangement. This must be used in association with apolicy of keeping crew protected inside the superstructure to limit injuries caused byfragments from externally detonating rockets.
Longer term measures
Add armour protection to the bridge. Protection against 7.62mm bullets can beafforded by an equivalent of 15mm of Rolled Homogeneous Armour (RHA). Thismight be achieved by bolting 10-12mm of RHA to the outer faces of the existingbridge structure. If armour is added to the bridge there will be a risk of spall,(fragments of plating), from the armour if it is attacked by a more severe threatthan the protection is designed to defeat. This can be mitigated using a spall lineras the innermost layer of material inside the bridge. Overall the additional weightof armouring the bridge of a vessel in this way could amount to between 4-6 tonnesand cost between 25,000 and 40,000 to purchase.
The longer term measures may be considered at the design stage of a new build vessel.Cost implications could be mitigated to some extent by incorporating the hardeningof the bridge structure as a shipyard standard cost, rather than an owners requestedadditional requirement. Weight considerations can also be mitigated by use of Kevlaror similar, however while weight is considerably reduced, cost is proportionallyincreased.
The results of the study clearly demonstrate the following:
- The risk of a fatality in a vessel where the bridge windows have been protected isconsiderably reduced (in percentage terms) compared to a vessel with no bridgeprotection.
- The additional risk reduction achieved by hardening the steelwork is negligible, withthe exception of the 12.7mm DhSk heavy machine gun.
An attack using an RPG would be expected to cause increased vulnerability. Intests conducted although RPG fire was able to penetrate the armoured bridge, thewindows did not shatter inwards causing fragmentation. Secondary fragmentationwas the dominating result. The absence or reduction of primary fragmentation givesa lower probability of a fatality. In order to provide effective crew protection froman RPG attack to the bridge, the fitting of RPG netting or double chain link fences isrecommended. This provides a barrier preventing the ordnance striking and detonatingon the bridge structure, mitigating the risk of fragmentation injuries to the crew.
The results ofthis study enablerecommendations forboth existing vesselsand vessels to be built.
Recommendations for Existing Ships
In modifying an existing vessel, the simplest and most effective protection for thebridge is the installation of shatterproof film to the windows. As a guide it would cost inthe region of 2,000 to protect the bridge windows of a single vessel.
The conclusions of the report only show a marginal improvement of protection if thesuperstructure bulkheads are hardened. Bolting on of 10mm RHA plating to a ballisticstandard that would defeat an AK47, (EU Standard 1522 – FB6) would cost in the regionof 25,000 – 40,000, and would incur additional weight of approximately 4-6 tonnes.
Full protection may not be cost effective. However a partial installation, carefullysited may be beneficial, for example on the bridge wing area where it may provideadditional protection from incoming projectiles on the beam of the vessel.
Existing vessels may provide additional protection against an RPG by fitting eitherproprietary net technology around the outer edges of the superstructure deck, or byfitting double chain link fencing.
The former is available from the majority of defencemanufacturing companies but is expensive. The latter is effective and cheap to install.
Recommendations for New Build Tonnage
For a new build vessel the following protective measures should be considered at thedesign stage.
Learn more details by reading the study issued by OCIMP on Bridge Vulnerability (please click at image below)