EAC? Marlin and Dorrie rode it south looking for Nemo!
Southern Princess
John & Irene Hunt
Wed 21 Apr 2010 02:04
|
Noon 21/04/2010. Position: 33:30S
155:24E
Distance to go: 206 nautical miles (400
kilometres)
Today's blog is for the sailors!
Email to Bruce early (05:45) today. Subject:
Houston we have a problem!
We have run into a counter current probably from the Eastern Australian Current. Our speed through the water at these revs is about 6.2 knots. Around 21:30 last night (all Sydney times) our SOG dropped to 5.4. By 22:30 it was 4.2knts. And until 02:30 this morning averaged 4knts. In other words a current against us of around 2 knots. (The paper chart suggests 1 to 1.5knts westerly flow) The current increased to 3.5 knots around 04:00. Our position at 21:30 last night was 33:42.718S 156:47.715E and our CMG for the entire period to 04:00 was 255M. To achieve this the pilot had us on course of around 235M indicating that the current was pushing us north. During this period the sea temperature was 20.6C. I didn't record it but mid Tasman it was around 18.5C At 04:00 this morning at position 33:43.610S 156:14.631S (sea temp 20.7C and course steered 235M to maintain a 255m CMG) I decided to turn northwards to a course of 295M which together with the current has given us a CMG of 310M. It is now 05:45. Our current boat speed is 6.4 knots. SOG is 5.8 knots. CMG 310M. The instruments show a Tide Set of 058M ( I assume this is TO that direction) and a Tide Rate of 1.4 knots. Water Temperature 20.7C. We are low on fuel and currently heading away from Sydney. There is no wind at all. Questions: Have you access to a sea water temperature satellite picture? If so is it possible to plot us around the problem? Maybe get us into the EAC and we can ride it south al la Nemo's Dad? We are currently 206 NM east of Newcastle. We are just south of the Taupo Sea Mount. Any ideas? Follow up to Bruce at 07:15 today
Bruce,
We are now past the Taupo Sea Mount and have managed to bring the yacht around to 250m which is our track to Sydney. Still only doing 5.5 knots and it seems we still have a 1 knot current on 040M. Suggest that it was the Taupo Sea mount causing the problem and if you agree don't bother with all the extra work on sea temperatures. Out of interest, how far off the coast is the EAC typically and how wide is it normally? Cheers JH
For those without a chart, the Taupo Sea Mount is
an area about 200nm east off Newcastle where the sea level rises from around
5000 metres deep to 120 metres in a short distance. Just north of there is the
Barcoo Sea Mount which again goes from 4800 metres to 251 metres. Ian from
Taupo, New Zealand denies any responsibility.
Bruce's Email; Subject: Hopefully a solution, Princess!!
Hi John
You ran into an eastward flowing filament of the EAC. There is an anticlockwise eddy centred near 34:20S 153:45E with another clockwise eddy near 31:30S 155:45E. There should be a weak westward flowing current once you get to around 155:00E at your latitude. Your best option is to head due west as this should get you across the current from the SSW on the eastern side of the southernmost eddy and into the slightly assisting current. There appears to be a 2.5kt to 3kt SSW flowing current building once west of 153E so by heading west you will then get this assisting current down to Sydney. Also the NNE sea breeze builds fastest from the coast outwards and the bulge in the coast caused by the Port Stephens area should enable you to pick up the breeze faster this way. Your winds should shift NE 5/10 knots during the afternoon and tend NNE 10/15 knots in the evening. they will probably ease a touch early Thursday back to 8/13 knots from the N to NNE then increase again from the NNE to 13/18 knots by noon and 15/20 knots briefly mid to late afternoon then ease back again as sea breeze effects decrease. So the strategy is to go due west until you start to experience the SSW flowing component of the EAC then follow Nemo down to Sydney town. cheers Bruce We have now been motoring for days. Ryan says this
trip has just been like a day sail! Sailed for 1 day and motored the rest. The
tanks will be bone dry by the time we arrive.
Lunch today is bacon & egg pie compliments of
Avelyn. Thank you from all of us. Only two bottles of red left so we have to
make it to Sydney soon! At this stage it looks like Thursday evening but with a
bit of breeze we might make it sooner. Who knows?
One more tomorrow!
John Hunt
Southern Princess _/) |