Back to all news

Limpet Mine Threat in Arabian Gulf

Sourced: @thestevennabil on Twitter

The threat to oil tankers operating in the Arabian Gulf has evolved during the last 18 months at an alarming rate. Following the seizure of the British flagged tanker Stena Impero on 19th July 2019 by Iran’s Islamic Revolutionary Guards Naval Forces (IRGC-N) tactics have evolved into Limpet Mine attacks on tankers.

On 13th June 2019, the tankers Front Altair and Kokuka Courageous were each attacked with two limpet mines attached to their hulls by small boats. One of the Limpet Mines on the Kokuka Courageous failed to detonate and was photographed in situ on the hull, before being removed by an Iranian Patrol boat.

A further four tankers; Amjad, Al Marzoqah, A Michel, and the Andrea Victory, were attacked off Fujairah on 12th July 2019, with each tanker suffering damage below the waterline.

The latest incident on 31st Dec 2020 was a limpet mine attack on the Tanker MT Pola, discovered during a ship-to-ship transfer with the Nordic Freedom. Footage of the limpet mine on the hull directly above a fender has highlighted the threat and the need to counter it. The limpet mine used has been generally accepted as one of Iranian manufacture, having first been seen at an arms show in 2015.

Traditionally limpet mines would have been disposed of by Naval EOD diving teams using equipment such as low explosive cartridge driven Limpet Mine Disposal Equipment (LMDE) developed in the late 1960s, however trials conducted in the 1990s demonstrated that this was ineffective against modern limpet mines.

This capability gap resulted in the development of alternative systems, one of which is the Vulcan Counter Limpet Mine System (VCLMS) by Alford Technologies Ltd. VCLMS utilises a small high explosive shaped charge which has been shown to be highly effective in the disposal of limpet mines and is in service with various Navies around the world.

The images of the limpet mine attached to the hull of the MT Pola highlights the complexity of the disposal task. Based on information available, much of which is unconfirmed, it would appear that the limpet mine was placed either by small boat or diver under the cover of darkness, before the two tankers came together for the transfer process. The limpet mine appears to be around 2m to 3m above the waterline immediately above a fender, which due to the movement between the vessels presents an immediate threat to the tankers and life – should detonation occur.

There are many images of the limpet mine to be found on social media, however those with an eye for detail will notice that there appears to be two variants, with different sizes and position of fittings.

The limpet is reportedly made of Aluminium and composites, is 550mm in diameter, 320mm in height and 42kg in weight.

Source: https://www.portandterminal.com/explosives-team-working-to-diffuse-mine-stuck-on-oil-tanker-in-iraq/

Modern limpet mines are usually fitted with anti-removal devices, however the limpet mine in question appears to be identical to the one removed from the hull of the Kokuka Courageous by the Iranian Patrol boat. This indicates that the anti-removal was either not fitted, armed, or was gagged prior to removal, however in this case, it is best to assume the worst-case condition exists and the mine should not be removed or jolted. The lack of technical information on the limpet mine also needs to be considered.

The immediate course of action is to reduce the risk by separating the tankers. Cargo could be pumped away from the area and the hold flooded with water to further reduce the threat and risk of a major incident.

Thereafter, selective disruption using VCLMS or disruption using Pluton is most likely to provide the best outcome. However, ultimately the choice is down to the EOD operator and the equipment available on the day.

Please note: I have left a substantial amount of information out of this, so as not to compromise procedures, however I think it’s a task any Maritime EOD operator would relish (I certainly would), and I wish the operator tasked to this a successful, professional and safe outcome.

Written by Andy Carss, Technical Project Manager.

Read this article on Linkedin here.