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HomeDenison Canal
MAST recommends:


  • Mariners are advised not to attempt to enter Blackman Bay through the Narrows in heavy north-easterly conditions
  • Only vessels with a shallow draft should transit the Narrows  and only after the skipper has sought local knowledge.
  • Navigate only at high tide and in daylight hours

Tidal Streams

  • The main stream of the flood tide runs into Blackman Bay – ie, in a north-easterly direction at the Denison Canal and a south-westerly direction at the Marion Bay Narrows. The reverse applies for an ebb tide.
  • Tide times can be calculated with reference to tide tables with the following adjustments:
    • Flood Stream commences 2 hours 27 minutes after low water at Hobart
    • Ebb Stream commences 2 hours 16 minutes after high water at Hobart

Remember to adjust for daylight saving time. Mariners should remember that tide conditions may differ depending on factors such as barometric pressure, prevailing winds etc.

Click on MARION NARROWS link below for
Marion Narrows information Dec.2020

It must be remembered that transiting the Marion Narrows is best performed when there is no current against the waves. This can stand up the waves and make negotiating the channel difficult.
You will  require about 45-0 minutes to cross Blackman Bay at 4-6 knots. Therefore arrive at the canal, or the "narrows" about 1 hour 15 minutes after high tide in Hobart. This will provide a flood tide at the narrows or the Denison Canal.

Marion Narrows.

Please note that there are many oyster farms within Blackman Bay. The approximate positions of these may be viewed by selecting the following link "Farm leases in Blackman Bay"