Vessels proceeding via the GNEC or Inner Route are limited to this draft. The draft limitation is confirmed in Annual Australian Notice to Mariners No. 23 (2007) from the Australian Hydrographer.
The maximum draft between Central Queensland Ports and Hydrographers, Palm or Grafton Passages is limited only by the permissible draft at the loading port.
Vessels at maximum draft are able to transit Torres Strait 365 days per year but will require tidal assistance. On some days of the year there is only one tide with sufficient rise to enable a safe transit with the required under keel clearance (UKC). The maximum delay a vessel could anticipate whilst awaiting a tide varies with the season, generally being less during the north-west season from the end of November to March.
Vessels drawing in excess of 10.5m will require some tidal rise to transit Varzin Passage allowing for 1m UKC. The Masters of east and south bound vessels should advise their ETAs at Booby Island PBG and draft when requesting pilotage assistance. Pilots at our Thursday Island pilot base will calculate and advise deep draft vessels of the relevant tidal windows for safe passage with the required UKC.
Under Keel Clearance
Minimum under keel clearances (UKC) required are as follows:
|Draft||Varzin Passage||POW Channel|
|Less than 11.90m||1.0m||1.0m|
|11.90m or Greater|| 1.0m|| 10% of draft|
The Torres Strait is a shallow but fortunately not a narrow channel with the attendant canal effect. Consequently the designated UKC for various drafts is more than sufficient to cater for squat in this area. The 40 miles between Booby PBG and the eastern end of the Strait is conducted at speeds in keeping with the vessel’s draft and the water available at any given time. Average passage time for a large deep draft vessel is about 3.5 hours.
There are five tide gauges in Torres Strait. They are located at:
Turtle Head (Hammond Island)
Ince Point (Wednesday Island)