At the time of the incident, the submarine was at periscope depth operating its diesel engines to charge the battery.
Standard pre-planned procedures were immediately executed and the situation was dealt with quickly.
The submarine surfaced as part of this normal response. The incident has been traced to a split in a hose on the submarine's weight compensation system.
No personnel were injured and Farncomb is currently returning to Pearl Harbour in Hawaii to replace the hose. An investigation is yet to commence.
There are number of hoses fitted to systems in the Collins class submarine that use the supply of sea water as part of their operation. Weight compensation is one such system, moving water in and out of the submarine to maintain neutral buoyancy.
Following the failure of a sea water cooling hose in HMAS Dechaineux in 2003, there were immediate changes made to procedures and the development of equipment changes commenced.
One of these changes was automation of the closure of all hull valves should a similar situation arise. This change has been installed in HMAS Farncomb.
Farncomb is currently on a 13000 nautical mile, five month deployment having departed her home base in Western Australia in May of this year.
The submarine has spent the last 15 days at sea participating in Exercise RIMPAC, which has included the recent successful firing of a Mk 48 torpedo to sink the 12,106 tonne former USNS Kilauea.