HMAS FARNCOMB ON 23 AUGUST 2011
10 September 2011
Reporting on 10 September 2011
The Chief of Navy Vice Admiral Ray Griggs, AM, CSC, RAN says the report in the Australian newspaper today that a Navy submarine was involved in a ‘near disaster’ last month are sensationalist and will have upset the families of the Navy’s submarine force.
The responses provided by the Defence Department to the newspaper concerned and a copy of a Defence Department media release on the article are detailed below.
Date responses provided: 06/09/2011
1. Where was Farncomb (ie; location) and what was the purpose of her being at sea when
the incident happened?
FARNCOMB was at sea off the coast of Western Australia conducting operational training. At the time, it was at periscope depth.
2. When the main propulsion failed, did the crew seek to engage the emergency back-up
mode of the main motor? Full details please.
In a standard response to a propulsion failure, the crew immediately commenced procedures to
restore propulsion on the main motor in emergency mode.
3. Is it correct that this also did not work, leaving the submarine with still no propulsion?
There was a delay in restoring propulsion in emergency mode, which led to the Commanding
Officer’s decision to surface. On reaching the surface, propulsion was restored in emergency
4. Is it correct that the submarine, without propulsion, then tilted on an angle (front end
up), if so roughly what angle?
After the propulsion failure, the submarine was ordered below periscope depth to investigate the
propulsion defect. In doing so, the submarine assumed a bow down angle which is normal.
5. Is it correct that the submarine took in water because it was snorting at the time and so
water came down the snort as it went under? How much water in tons did the submarine
take on during the incident?
The submarine did not take on water. In response to the propulsion failure, the submarine
stopped snorting. When a submarine stops snorting, hull valves are shut. At the same time, the
snort mast and exhaust system, both external to the submarine pressure hull, fill with water
(which is the normal state when not snorting). As these fill, compensating water is pumped out of
the submarine to maintain neutral buoyancy. As the snort mast and exhaust systems fill with
water faster than compensating water is pumped from the submarine, there is a period during
which the submarine is heavy.This is always the case when a snort is stopped in response to
6. Is it correct that the submarine then began to slide deeper without propulsion?
No. In the prevailing sea state, the Commanding Officer chose to take the submarine deep to
investigate the propulsion defect. On reaching the ordered depth, propulsion in emergency had
not been restored. Even though the Emergency Propulsion Unit, which is independent of the
main motor, was manned and available during the incident, the Commanding Officer then chose
to surface to investigate the propulsion defect.
7. Is it correct that the commanding officer then ordered a partial blow of the ballast to stem the downward movement? What was the percentage of that initial ballast blast (ie; how much water did the CO seek to expel in the first ballast blast?)
To reach the surface the Commanding Officer blew main ballast tanks using a normal blow.
8. Is it correct that the initial ballast blast did not stem the downward movement, so the CO
order a full emergency blow of the ballast tanks? Did this remove all the ballast water?
No. The submarine was already ascending when the Commanding Officer chose to increase the
rate of ascent by using the emergency blowing system.
9. At what depth did the submarine sink to before it began to rise as a result of the
The submarine was already ascending prior to use of the emergency blowing system. The
submarine remained well within its depth envelope throughout.
10. How long – roughly did the submarine sink for and how long (roughly) did it take to
break through the ocean surface after it reached its lowest depth?
The specific manoeuvring characteristics of the submarine are classified; however, the timing of
movements was within normal operating parameters, which had been previously proven during
11. Is it true that once back alongside at Stirling, subsequent testing of the emergency
back of mode of the propulsion unit failed to detect any fault?
Subsequent testing of the propulsion system identified a defect on the propulsion switchboard,
which was subsequently rectified. A technical investigation is in progress.
12. Is it possible that the inability of the CO to engage the back-up mode was due to crew
error rather than technical problems. Full details please.
The incident is being investigated to determine the facts surrounding the incident.
13. How serious was the incident and what positive aspects and lessons were derived
Standard procedures were employed to recover from this propulsion failure while snorting. These
procedures are regularly exercised and the systems used are routinely tested during the licensing
process that follows each submarine’s maintenance period.
14. Have any of Farncomb’s crew been granted stress-related leave?
We are not currently aware of any stress-related leave.
15. Any further comments, clarification or contextual points which Navy would like to make? Was a report made of the incident and is there an ongoing investigation?
The incident was reported, and a technical investigation is underway.
16. What has Farncomb done since the incident and where is she now?
Since the incident, HMAS FARNCOMB has rectified a defect on the propulsion switchboard,
participated in the Fremantle Maritime Day, and has since returned to sea. The submarine is
currently participating in exercises off the West Australian coast
ADDITIONAL REQUEST: INCIDENT INVOLVING HMAS FARNCOMB
Date responses provided: 07/09/2011
1. Why did the CO order the sub to dive when it had no propulsion in order to restore the propulsion system? Full explanation please. This appears to make no sense, especially given that moments later he chose to ascend to the surface in order to try to restore propulsion?
The restoration of propulsion in emergency mode while a submarine remains dived is a standard procedure that is routinely drilled. This is particularly important in operational situations when a submarine does not have the option to surface in the event of a propulsion failure. It is equally prudent to remain dived in other situations, such as high surface sea state. In this case, the Commanding Officer took account of the prevailing sea state on the surface and made the valid decision to investigate the propulsion defect at a safe depth, where the submarine would remain stable. When propulsion in emergency was not restored within the expected timeframe, he made the equally valid decision to surface to continue defect investigation. The reason for the delay in restoring propulsion in emergency remains the subject of a technical investigation.
2. During the cut off of the snorting, is it true that a crew member mistakenly enacted a command for water to come into the snort mask and exhaust rather then out, effectively increasing the weight load of the sub at the time it was already heavy?
Whenever a submarine stops snorting and proceeds below periscope depth, the snort mast and exhaust system will be filled with water, preventing their damage due to external water pressure which increases with depth.
3. You say the co ordered the sub deep to investigate the propulsion issue. What depth did he order the sub to go? Precise figure in metres please.
The initial incident occurred at periscope depth, which is approximately 20 metres. In such an incident, the submarine will be ordered to what is termed safe depth, which is sufficiently deep enough to avoid all surface shipping, but also well above the maximum operating depth of the submarine. This allows the submarine a large margin of depth movement while remaining safe.
4. How did the sub go down to that depth in a controlled manner without propulsion given the heavy weight? Full details please.
The submarine retains residual speed after a propulsion failure. The Collins class submarine can also manoeuvre well at low speed.
5. When the sub reached that ordered depth, is it true that the submarine continued to descend on an angle because there was no propulsion to prevent further descent or to straighten the sub? Full details please.
During the delay in restoring propulsion in emergency, the residual speed would have declined. Because the submarine was still heavy as compensating water was being pumped, the Commanding Officer chose to blow main ballast to arrest descent.
6. What was the deepest level which the sub descended to? Precise figure in metres please. At what precise depth in metres did the first ballast blow take place.
The operating depths of submarines are not openly discussed. The first ballast blow was ordered soon after the submarine reached safe depth.
7. If the first ballast blow was sufficient to stem the descent and make the sub rise, why would the captain blow emergency ballast? This makes no sense unless he was uncomfortable with the situation. Full explanation please. At what precise depth in metres did the emergency blow take place.
The submarine was ascending when the Commanding Officer ordered emergency blow of main ballast. The reason for this was to increase the rate of ascent. This avoided a slower ascent, ensuring the submarine would not remain in shallower depth zones for longer than necessary where it would be unable to avoid surface shipping.
8. You have failed to answer question 11. I asked whether tests on the emergency back up mode had detected faults in that back up system, not in the mainstream propulsion system? So did it or was it a crew member who was at fault?
As answered yesterday, a technical investigation remains underway to determine the facts surrounding this incident.
9. You imply in your answer that the epu was available as if it were built for this situation but is not the case that the epu is not designed to assist a sub at depth. Is is designed for underwater emergencies like this or is it designed to restore propulsion on the surface? Can an epu recover a sub at depth in a situation like this.
The Emergency Propulsion Unit is designed to operate throughout the operating depth of the submarine. During the standard procedure in response to a propulsion failure the Emergency Propulsion Unit is manned, providing the Commanding Officer with another means of propelling the submarine. The Emergency Propulsion Unit does not have the speed range of the main motor; however, can propel the submarine while dived, which would be sufficient to maintain control of the submarine in such situations.
FOLLOW-ON QUESTION - HMAS FARNCOMB
Date response provided: 08/09/2011
1. Is Defence able to confirm that the CO at the time of the recent HMAS Farncomb incident was CO Glen Miles?
Yes. Commander Glen Miles was in command of HMAS Farncomb on the August 23.