Michael McFadyen's Scuba Diving Web Site
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My Yachting Adventures
Below is a list of links to the main pages about my yacht, Catlypso and My Yachting Adventures:
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  • My Yachting Adventures.
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    Michael's 4WD Trips
    Click here for a list of my Four Wheel Drive and Camping Trips.
    Home Brewing
    Click here for an article about Home Brewing.
    Sydney Dive Site Hints
    "Red Indianfish seem to prefer northern sides of the entrances to bays and harbours"
    Southern Entrance - Great Detached Reef
    Michael McFadyen's Scuba Diving - Southern Entrance, Queensland Great Detached Reef is located at the northern end of the Great Barrier Reef off Queensland, Australia. It is about 125 nautical miles (230 kilometres) from Thursday Island in the Cape York area (the pointy tip of Australia) and 75 nm (140 kilometres) from Lockhart River. The is 45 nm (85 kilometres) east-north-east from closest point of the Australian mainland, Cape Grenville. It is just over 4 nm south of Raine Island, the largest green turtle nursery in the world.

    Cape YorkCape York
    A chart showing the location of Great Detached Reef (bottom right)
    and Thursday Island (top left)
    Great Detached Reef - Southern Entrance
    is located at the bottom of GDR and is obvious

    Great Detached Reef is a reversed C shaped reef made up of a number of separate sections. It is located a little off what is the main outside section of the Great Barrier Reef, although here that reef is merely a series of small bommies or reefs. Great Detached Reef is 11.5 nm from north to south and 8.8 nm east to west. The west (open) side of the reef has a series of bommies and small reefs along a large part of its length.

    There are only a couple of boats that travel to this area, one being Kalinda which routinely does full boat charters there in November and December. Another boat does some trips there and one more might go there once or twice a year.

    Kelly and I travelled here in November 2016 on Kalinda with fellow members of St George Scuba Club when we chartered the whole boat. We flew into Horn Island (next to Thursday) and started our trip from there.

    There are two entrances to the Great Detached Reef lagoon (not counting the open western side). Southern Entrance is located between the southernmost section of reef and the section that runs from here north. The dive site is located on the southern side of the entrance and outside the lagoon. Its location is GPS S11Âș 48' 55.3" E144Âș 00' 57.4". The depth on the top of the reef is five metres and from here it drops steeply to 200 metres.

    Southern EntranceSouthern Entrance
    A typical section of reefAnother photo of the reef

    We anchored in about 25 metres and we dropped to the anchor and then headed south along the reef and wall. We dropped to 30 metres which has the best section of wall and gorgonias. After five minutes we gradually started a very slow ascent up the wall and then the slope. There are thousands of gorgonias on this dive, ranging from huge to small in size.

    As we go along we see lots of sharks, grey reef, white-tipped reef and black-tipped reef sharks. The reef has lots of vertical gullies that run from near the top of the reef down deeper. In these gullies and elsewhere there are lots of titan triggerfish and their nests. Luckily it they have not yet laid their eggs, so the triggerfish are not aggressive. I would hate to be here when the eggs are being guarded.

    Southern EntranceSouthern Entrance
    Kelly with one of the large gorgoniasKelly looks at an orangefin anemonefish
    from the anemone at left

    As well as the sharks and triggerfish, we see quite a few barracuda, kingfish, plenty of giant trevally as well as other species of trevally. We also see plenty of Moorish idols, long-finned bannerfish and butterflyfish. There are also a lot of parrotfish and two firefish.

    We also see a few nudibranchs and slugs, as well as some tiny yellow "bugs". They are obviously some sort of crustacean, but who knows what.

    Southern EntranceSouthern Entrance
    Inornate chelidonuraA whole lot of some sort of "bug"

    We come back a bit shallower and gradually ascend again to 10 metres where we spend 15 minutes before ending the dive with more than 15 minutes around the five metre level.

    We dived here in November, the water temperature was about 28ÂșC, visibility about 20 metres. A really good dive site.

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    Website created 1996!