Tac Talks: Mine Counter Measures off the Australian Theatre

Introduction

Australia is a sun-kissed and lucky country. We’re fortunate enough to live and work in a peaceful, quiet, clean and beautiful land with the best sandy beaches on earth. This fortunate happenstance however poses unforeseen military challenges to the defence of our nation, and the operational effectiveness of our indigenous mine hunting forces.

Since the decommissioning of the Ton Class Minehunters in the mid-1980s, the RAN primary area of operations for Surface Mine Counter Measures (SMCM) has been in the Australian theatre, and particularly on the east coast of Australia. The Ton Class Mine Hunters, designed in the UK to mine hunt in all environments, were to be replaced with the Bay Class Minehunter Inshores (MHIs). These would be six specialist inshore platforms stationed at six separate priority ports around Australia and tasked with ensuring the maintenance of Sea Lanes of Communication to those ports and in their immediate vicinity to ensure Australia’s Export/GDP. Due to various issues with the Bay Class Minehunters, only two entered service, and they never achieved reliable operations on the Australian Theatre.

As a result of this, Australia was without an effective, reliable and agile mine hunting capability from the decommissioning of the Ton Class in the mid-1980s, until the commissioning into service of the new Huon Class Minehunters in 2000. These new Mine Hunter Coastals (MHC) were more capable, and importantly more agile than their plagued predecessor in that they could and would transit between operating areas. They also had operational benefits over the Bay Class, including a GRP design (MHC) rather than a foam fibreglass design (MHI) that required less maintenance and was more shock resistant to mines, a variable depth UK designed 2093 sonar able to penetrate layers in the sea column and the ability to operate 24hrs versus the Bay Class 12hrs.

HMAS Choules' embarked MRH-90 Taipan helicopter, call sign ‘Hat Trick’, conducts passenger transfer serials with HMAS Huon during the ship’s transit to Vanuatu. Photographer: LSIS James McDougall.

This being said, they were like anything in the military a compromise, and these small, top heavy, round hulled craft were ill suited to the ocean transits and foreign ops that defined the Ton Class, and this restricted their operations largely to the East Australian Theatre.

And therein lies the problem. Those same pristine beaches of hard packed sand, broken shell and rock that we cherish so much, clean and free of litter and hard rubbish extend far beyond the surf where we’re all familiar with them. In fact in the majority of the east coast of Australia, the seafloor is much the same environment, and while this may seem like a boon of nature to have such pristine, unbesmirched coastlines, it presents several challenges to our ability to counter and protect our civil and military shipping against hostile mine warfare threats by foreign agents. These conditions present an ideal environments to conduct sonar based MCM operations; the smooth, firm seafloor is easy to distinguish from any potential mine like underwater contacts, and classification is relatively straight forward. Constant operation in preferred environments where we can ensure ideal conditions for our equipment can lead to a false sense of certainty in our ability to perform at our best at all times.

Royal Australian Navy Minehunter HMAS Gascoyne completes a route survey of Eden Harbour in NSW.

This changed dramatically in 2018 with the advent of the MHC North East Asia Deployment 18 (NEAD18). This deployment would see two MHCs (HMA Ships Gascoyne and Huon) deploy further than any MHC before them to the Korean peninsula as well as Japan to partake in international mine hunting exercises between these host nations, the United States and several guest nations. With this in mind, both MHCs proceeded north with a level of trepidation for what lay ahead in terms of mine hinting, reports from our international partners indicated that the conditions, particularly in Korea were some of the most challenging to be found in the world.

On commencement of the exercise, it was quickly determined that the seabed was a deep and soft mud with a significant layer of easily stirred silt. Mine shapes in the area had sunk up to 80 percent of their length into the seabed, leaving only the smallest portion visible to be countered. These are some of the most dangerous environments to conduct MCM operations in. Just because a mine has sunk into the sea floor, does not make it any less dangerous to the shipping it is designed to counter. And if completely buried MHCs (lacking a minesweeping capability) do not have an organic means of detecting or rendering them safe. That said it is pleasing to note that the 2093 sonar performed admirably with all exercise mines in the exercise area found in a most efficient manner.

Huon Class Minehunters HMA Ships Diamantina and Gascoyne arrive in Hakodate, Japan for a port visit during their Maritime East Asia deployment.

The primary challenge arose when it came to identify and counter the exercise mine shapes. To this day, it requires a physical Mine Disposal Vehicle (MDV) or diver to visually identify the contact and manually render it safe. As previously mentioned the significant layer of silt rapidly deteriorated the visibility, exacerbating the already poor visibility and making it impossible to visually identify the placed mine shapes. This was the first major lesson learnt from our operations in these foreign environments. 

Doctrine that is well versed of low approaches that had been highly effective in Australia simply were not feasible in these conditions. After trial and error, a method of approaching the contact further off the seabed at slower speeds proved to be the most effective method of identifying the contacts. Even with this approach method, only a 5-10 second window of ‘eyes on’ could be achieved before it disappeared into a cloud of black silt.

A further challenge that presented itself in Korea, not seen to the same extent on the Australian Station is the prominence of fishing nets, bait boxes and other debris in the vicinity. These pose several issues for mine hunting. Firstly all of these obstructions present themselves as Mine Like Contacts (MILCOs) requiring time and effort to correctly identify them. Further and more pressingly they present potential hazards for both the MHC MDVs as well as divers. Both crews displayed a versatile and professional approach and overcame these issues in short time to meet exercise objectives.

A member HMAS Yarra's crew, Leading Seaman Electronics Technician Dylan Waters controls the tensioning winch of the Double Eagle mine disposal vehicle during Exercise CUTTLEFISH.

The experience gained from operating in this environment is priceless. Our coalition partners have gained a respect for the RAN MCM community and the capability we can provide if needed. The RAN will continue to operate outside of the Australian AO with the second deployment of two MHCs to NEAD 19, where we will build on the lessons learnt last year. The experience gained from these deployments will provide the RAN with a much stronger MCM capability with the capacity to work in multiple environments and ensure our ability to protect against mine threats of all types into the future.

About the Authors

LEUT Northend is currently serving as Operations Officer in HMAS Gascoyne. He completed his Mine Warfare Officers Course in February 2019 having previously served in HMA Ships Huon and Gascoyne as Officer of the Watch.

CPOCSM-MW Simon East is currently serving as Operations Room Supervisor in HMAS Gascoyne. In his 27 years in the Navy he has served in Bay Class MHIs and Huon Class MHCs, 15 years of which have been spent as a Mine Hunting Director.