the Degree Confluence Project

Australia : Northern Territory

5.8 km (3.6 miles) NW of Northwest Vernon Island (Island), NT, Australia
Approx. altitude: 0 m (0 ft)
([?] maps: Google MapQuest OpenStreeMap ConfluenceNavigator)
Antipode: 12°N 49°W

Accuracy: 8 m (26 ft)
Quality: good

Click on any of the images for the full-sized picture.

#2: South towards NW Vernon Island #3: GPS #4: Keith and the boat #5: Aviation map of the general area #6: Detailed marine chart with picture locations #7: Location A, Vernon Island #8: Location B, the Vernon reef edge #9: Location C, Mangroves on Melville Island #10: Location D, Irrituti straights

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  12°S 131°E  

#1: North towards Melville Island

(visited by Jeremy Watson and Keith Watkinson)

16-Apr-2005 -- The point lies at sea in the Clarence Strait midway between Melville Island to the North and the Vernon Islands to the South with the Northern Territory of Australia beyond. It is only about 30 nautical miles from Darwin by boat. We left Darwin at 7:30am on a smooth sea in Keith’s excellent 5.8m Sportfish, cruising along with no drama at about 22kts and by 9:20am we were at the spot.

The area is a maze of reefs, oyster rock and coral interspersed with holes and channels up to 60m deep. We scheduled our arrival for the top of the tide so we could pass over most of the reefs safely and avoid the tidal race. Nevertheless, the eddies and upwellings made getting on station very hard and swimming in it rather spooky. So, why swim in it? Well, Jeremy thought he could do a better job swimming than Keith could manoeuvring the boat so he went overboard with the GPS in a map case, that was before he figured that even at the turn of the tide there was still a 2.5kt current through the reefs heading into the Van Diemen Gulf.

It’s actually a great place to dive if you are careful, especially on the neaps like today. The area is full of coral, the turbidity in Darwin harbour allows only sponges to grow so the Vernons are a treat. We were originally planning to take our pictures at the sea bed because we thought it might be on coral but it turned out to be in a 22m deep channel and it would have been dark, empty and featureless at the bottom.

Predictably, there wasn’t much to see at the surface either; the East and West views were of open sea to the horizon so these pictures have been omitted. The North view is of Melville Island 4.2 nm away and the South view shows North West Vernon Island 2.5 nm away. Melville is the largest island off the Australian coast after Tasmania but is only very lightly populated. The whole island is Aboriginal land and continues to be settled by the Tiwi as they have probably done for millennia. The small community of Pickertaramour lies only 11 nautical miles in from the coast. Like all the other Vernon islands, NW Vernon is uninhabited.

Since there wasn’t much at the point to give an impression of the environment we decided to record the nearest adjacent shorelines on Melville and North West Vernon Islands. The exact locations of the photographs are shown by the yellow flags A,B,C,D on the Nav chart. The green areas on the chart can dry at low tide but we still had 1.5m through the Irrititu strait on the ebb. The Picture A is as close to North West Vernon as we could get the boat, Picture B shows the oyster encrusted reef that stopped us getting any further, so North West Vernon stayed uninhabited. The water is warm, it’s not a wetsuit in the picture it’s a stinger suit made of Lycra. It provides essential protection against the rather nasty local box jelly fish, Chironex flekeri; my dive book says "If the patient is still breathing after 20 minutes he has every chance of survival"!

Picture C is of the Melville Island mangroves. To go ashore you have to climb through those mangrove roots keeping a careful lookout for the crocodiles as you go, and then if you get there you are entering Aboriginal land for which you need a permit from the Northern Land Council obtained before the trip, so we stayed in the boat. Picture D is the strait that cuts the little island of Irrititu (to port) off from Melville Island itself, just perfect crocodile territory but they stayed out of sight in the muddy estuarine water. After an interesting passage through the Irrititu strait the return was even flatter than the voyage in and was helped along by a very nice antipasto, baguettes and cold beer to finish off the 140km round trip.

Our EPE was 5m and the nearly all zeroes were heroically achieved by Keith steering on the boat’s Furuno while Jeremy crawled around the deck with the Meridian. After this novel experience of trying to get the zeroes to line up in a boat at sea I have to say we developed the greatest admiration for the prolific confluencer Captain Peter who regularly manages to steam a huge ocean-going freighter through confluence points at 17kts with this sort of accuracy.

It was hard trying to explain why we were doing this thing. "OK, so you're going all the way to the Vernons but you're not taking rods or gidgees? And you're not taking any dive gear either? And you haven't even got any crabpots! So, tell me again what is it exactly you are doing out there?"

 All pictures
#1: North towards Melville Island
#2: South towards NW Vernon Island
#3: GPS
#4: Keith and the boat
#5: Aviation map of the general area
#6: Detailed marine chart with picture locations
#7: Location A, Vernon Island
#8: Location B, the Vernon reef edge
#9: Location C, Mangroves on Melville Island
#10: Location D, Irrituti straights
ALL: All pictures on one page
In the Beagle Gulf, between Melville Island and Vernon Islands.