The MAXIMUM draft for vessels transiting Torres Strait is 12.50m basis a 1.025 SW density.
Vessels proceeding via the GNEC or Inner Route are limited to this draft.
The maximum draft between Central Queensland Ports and Hydrographers, Palm or Grafton Passages is limited only by the permissible draft at the loading port.
Tidal Windows
Vessels with a draft up to 12.2m are able to transit Torres Strait nearly every day of the year provided the tidal variation is in accordance with the tidal prediction. On some days of the year, there is only one tide per day 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 period from the end of November to March.
Masters of vessels with drafts from 12.2m – 12.5m should indicate the possible days of the intended transit and Torres Pilots’ Operations team will revert with the windows and maximum drafts for those dates.
Tide Messages
Vessels drawing in excess of 10.5m will require some tidal rise to ensure the required UKC is maintained and safely transit Varzin Passage and Prince of Wales (POW) Channel in Torres Strait. Masters of east and south-bound vessels should advise their ETAs and draft at Booby Island PBG when requesting pilotage assistance. The 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 |
Torres Pilots use AMSA-approved UKCM system transit plans for Torres Strait as generated by AMSA’s UKCM System (developed by world leaders, OMC International). UKCM system transit plans will accurately calculate tidal windows and UKC for the duration of a transit and allow for the optimisation of vessel transit speeds. UKC outputs include calculations of squat and heel, and the forecast and prevailing tidal conditions for the Torres Strait UKCM system monitoring area. AMSA’s UKCM system allows Torres Pilots and vessel operators to plan and monitor the safe and efficient passage of deep-draft vessels transiting Torres Strait 24/7. Use of the system has been mandatory since 1 January, 2014. TP Pilots will assist Masters with use of the UKCM system.
Squat
The POW Channel in Torres Strait is a shallow waterway, but fortunately not a very narrow channel, hence vessels are not subject to the attendant canal or bank effects which can be experienced in narrow channels. Whilst the UKCM system accounts for squat as part of its UKC calculations, it is important that vessels adhere to their planned speed profile for each transit, so as to not induce excessive and unplanned squat. The 40 nautical mile transit between Booby PBG and the eastern end of the Strait is conducted at speeds keeping in mind the vessel’s draft and the depth of water available at any given time. Average passage time for a large deep-draft vessel is about 3.5 hours.
Tide Gauges
There are five tide gauges in Torres Strait. They are located at:
Booby Island
Goods Island
Turtle Head (Hammond Island)
Ince Point (Wednesday Island)
Nardana Patches
Tidal heights are broadcast on VHF Marine Channel 68 (156.425MHz)