Torres Straits Advice

[DefinitelyMe]

OK, Prince of Wales Channel it is. Thanks again Alan. Raymond, thanks too. You guys have convinced me that the Aussie authorities and prices might not be too bad after all. Regardless we don’t have the time to hang around unfortunately as we’re looking to be across the Indian Ocean before the Cyclone Season picks up too much.

Looking at the tidal stream predictions for Hammond Rock and the tide height predictions it looks like max W’ly stream more or less corresponds with low tide, whereas high tide yields slack or an E’ly current. How about at the Eastern end of the Straits? I’ve got the tidal info but can’t find stream predictions. I’m guessing you get more W’ly current on a flood tide as the Straits fill from the Gulf of Papua and the reverse on the ebb. Is that right? Having grown up in Bermuda and done most of my sailing in relatively tidally-benign places, this tidal business is not something I’m very confident with. I really appreciate the input. There’s nothing better than being able to learn from people who have actually done this stuff!

[Paul L]

Originally Posted by RaymondR

I ....
As for the cost well if you enter in say Bundaberg and cruise your way up the Queensland coast and across to Darwin for clearing out again you are going to get a lot for your money and if ammoritized over all the free anchorages and stops it will turn out to be dirt cheap.

Clearance in Australia is pretty steep. Not near as much as the Galapagos, but higher than almost all the other few dozen countries we've cleared in and out of. Apparently it costs a lot to look for termites OK if you are gonna spend time, not so good for a short stop.

[Alan Mighty]

Originally Posted by DefinitelyMe

Looking at the tidal stream predictions for Hammond Rock and the tide height predictions it looks like max W’ly stream more or less corresponds with low tide, whereas high tide yields slack or an E’ly current. How about at the Eastern end of the Straits? I’ve got the tidal info but can’t find stream predictions. I’m guessing you get more W’ly current on a flood tide as the Straits fill from the Gulf of Papua and the reverse on the ebb. Is that right?

Someone or something is wrong. From where are you getting your prediction of tide height?

Let's suppose you were wanting to transit Torres Strait from E to W on Sunday 12 August 2018. That's a day after the New Moon, so you would expect Spring Tides and maximum tidal streams.

Look at the tidal stream predictions for Hammond Rock.

I read for Hammond Rock on 20180812 as:
0035 west going current of 5.16 knots
0338 slack water
0629 east going current of 4.72 knots
0910 slack water
1251 west going current of 8.01 knots
1625 slack water
1921 east going current of 5.85 knots
2226 slack water

From that prediction and what I wrote (that at the E end of the strait expect the max tidal stream to be about 30 minutes before Hammond Rock and weaker - by weaker I mean about 1/3rd of the stream), I would guess that for around Saddle Island:
0000 midnight west going current of about 1.7 knots; and
1230 west going current of about 2.7 knots.


If I look at the tide height predictions for Thursday Island on 12 August 2018, I see:

0111 3.47 (high water)
0836 0.54 (low water)
1324 1.85 (high water)
1950 1.25 (low water)

So that might mislead me think to expect max west going tidal stream about half an hour before high water at Thursday Island.

But it's not that simple.

The complexity of Torres Strait is that the tides do not follow the simple sine curve of a regular semi-diurnal tidal regime. You cannot use the rule of twelfths, for example.

You can get away with it on spring tides, but neap tides can be really strange, to the point that with some neap tide days you can have a high tide in the Coral Sea at a time v close to a low tide in the Gulf of Carpentaria or Arafura Sea.

My advice:

1. use the published tidal stream and tidal height figures to plan your day of transit. Do not try to guess a pattern from a quick look at the tidal stream and tidal height figures. It's complex. And any simple pattern dissolves as you go from spring tides to neap tides and from month to month.

2. the published tidal stream figures for Hammond Rock are the only ones I know that are trustworthy. You can safely guess that tidal streams at the East end, around Saddle Island for example, are 30 minutes earlier and perhaps 1/3 the stream.

3. When the SE wind is blowing strongly (and sometimes producing waves up to 2 metres at the E end of Torres Strait), expect a west going surface wind current on top of the predicted tidal stream.

4. Although I used 12 August 2018 as an example above, I would not suggest you schedule your transit for spring tides and maximum tidal stream. Unless you can reliably motor or sail at speeds exceeding the tidal stream, fast tidal stream is tough. Even approaching the E end of Torres Strait, fast tidal stream days can see you with a 45 degree difference between your heading and your course over ground.

[Dave_S]

I have watched a couple of V'logs were people sail through the "Hole in the Wall" NW of Nhulunbuy and they have attempted to work out the correct arrival times to be there for slack tide and on each video they arrive to find it running. At least one of them had the smarts to work it out before hand and he knew it wasn't straight forward but still got it wrong.

Is there good information on this are or is it a show up and see type thing. From what you say Alan it looks like it depends on the size of the tides, I've also heard of 4 high tides per day in some areas through there.

[Alan Mighty]

Originally Posted by Dave_S

Is there good information on this are or is it a show up and see type thing. From what you say Alan it looks like it depends on the size of the tides, I've also heard of 4 high tides per day in some areas through there.

The tidal streams and tide heights are well predicted.

The Queensland tide tables, meaning the ones published by Maritime Safety Queensland, have the table of predictions of tidal streams for Hammond Rock.

The Qld tide tables also have tide height predictions for Thursday Island (and perhaps more).

Maritime Safety Qld also publishes the Blue Book, which has tide height predictions (High Water and Low Water for many places, and hourly predictions for a few such as the barge ramp on Hammond Island) for quite a few islands in Torres Strait.


Both the Blue Book and the Qld Tide Tables are available on the MSQ website.

As I noted earlier, the tidal regime in Torres Strait is one of the most complex on this planet. I listed some of the factors:

*the throughflow of Pacific water;
* wind driven surface current;
* the meeting of the diurnal tide regime (to the W, in the Gulf of Carpentaria) and the semi-diurnal tidal regime (to the E, in the Coral Sea) between 142E and 143E;
* a so-called equalising current trying hard to bring the level of the Pacific to the level of the Arafura Sea; and
* likely others of which I know naught.

The colonial govt of Queensland (i.e. pre-1857) put its agencies to the problem. Agencies of the Qld state govt and the Aus federal govt have worked since on the problem.

The tidal component is more-or-less settled and is captured in those predictions of tide heights and tidal streams.

The add-on components (the wind-driven surface current and the equalising current, which depends on relative sea surface levels which in turn depend on atmospheric pressure and so change in the El Nin~o/La Nin~a cycle) cannot be captured in predictions.

If you're of a mind to dig further, the crucial work was done by a relatively unheralded oceanographer Eric Wolanski in the 1980s. Eric has an astonishing personal story to tell: born in the Belgian Congo with ancestry in NE Europe (Poland, Russia). Still around James Cook U in Townsville.

Aus govt agencies have laid more detailed and elaborate work on Wolanski's foundations. And my guess is that if the federal govt threw more money at the problem, even greater understand would be reached.

Give me a minute to find some of the key docs and I'll post them here for 24 hours or so.

But the bottom line is:

1. you cannot outguess the tide heights or tidal streams in Torres Strait (you can get away with it for a day or two around spring tides, but after that ....). By that I mean that the Rule of Twelfths and the like do not work.

2. the published predictions do work.

[Alan Mighty]

Eric Wolanksi et al Currents in Torres Strait from 1988, a pdf about 878 KB.

See: Malcolm Riley, "Torres Tides not Strait" in Afloat, 2012: Weather - Torres Tides not Strait - the Rule of Twelfths

For the latest (from 2016) you'll need to search (because the publication on my hard disk is 10 MB) on the net for Frederic Saint-Cast & Scott Condie, "Circulation modelling in Torres Strait" Geoscience Australia/CSIRO. It's a pdf made big by graphics.

[barnakiel]

It is not an easy patch - reefs / currents / shipping / u name it.


Make sure you are well rested before you enter the navigation channel.


Sail safe.


b.

[Alan Mighty]

Originally Posted by barnakiel

shipping

Yes. Thanks for the reminder, barnakiel.

Let's imagine: you're sailing E to W and about to enter the E end of the Torres Strait, let's say around Saddle Island. And if you've a decent keel/underwater profile, you may be crabbing such that there's a 45 degree difference between your heading (where your bow is pointing) and your Course over Ground.

So what does the chap on watch in a motor vessel think?

If she is alert, she's tracked you on radar and the radar/ais has already calculated your CPA. If she doesn't have radar and you're not broadcasting AIS, then it's a smaller craft and might well be more agile than you. You hope!

Here're two AIS density maps, for those who are not averse to using marinetraffic.com for navigation: one at small scale so you can see from where they come and to where they go; and the other at mid-scale so you can see how many choose Prince of Wales and transit the whole Strait; how many use Endeavour Channel; how many do a mix; and how many are small shoal draft local vessels (including barges with local knowledge) that can do their own thing.

[theway]

Originally Posted by DefinitelyMe

We are double handed on a 36-foot yacht that usually makes about 125 miles a day and carries fuel for 3 days. Does this route sound reasonable? We don’t want to stop in Australia if it can be avoided because it’s bloody expensive and sounds like a bureaucratic nightmare. We want to be in South Africa before November so we can’t take our time :-(

...

I was in a similar situation a year ago wanting to get around Australia as quick as possible and on to the Indian Ocean (I was gonna clear in at Cairns). I decided to stay the year in Australia, Cleared in at Bundaberg and went down to Sydney and back up. I’m now moving north toward the top.

The word “expensive” is definitely relative but I found it to be reasonable for most things. I’m from the states so our dollar makes it more reasonable. Clearing in is not bad, very quick and very efficient, yes it does cost about $350-400USD and yes there is some paperwork (less than French Polynesia), and yes they might put a dog on your boat, and yes they check thoroughly for termites, but it’s well worth it if you stay a year. The year visa is another $100-$200... They didn’t check our bottom nor did they seem interested.

With that said, I’d highly recommend it. I was surprised and awe struck on a regular basis when cruising up and down the coast. I know plans can change so I thought I’d share that even though you sound fairly sure about skipping Australia.

austin

[DefinitelyMe]

Thank you all once again, especially Alan Mighty. You are correct in your post #18, and the person that is wrong is me! I was reading from the wrong #@&% column in the tide tables! Doofus. Its a wonder I've managed to stay alive all these years and not run into a reef or something by now making mistakes like that.

I've now arrived in Port Moresby, PNG and can report that the yacht club at least is superb. The clearance was wonderfully painless and the people are great.

The next problem is that the online yacht registration part of the pre-clearance formalities for Indonesia is not working and has not been working for at least two weeks. Another boat here gave up and have hired an agent to do the paperwork manually in Indonesia. Apparently yachts that are already registered online are OK, and more than one yacht can be included on a single account. So...... I don't suppose any of you lovely ladies or gentlemen have such an account and wouldn't mind us piggybacking on it?

As for the Straits...... the plan is: turn up at the Eastern end (at the Bligh Entrance) at dawn one day and sail as fast as possible. Anchor at dusk and ask the nice Australian aeroplane people for forgiveness if they object. Set off again at dawn the next day and time the last part of the transit in accordance with the tidal stream at Hammond rock, bearing in mind the things you said Alan about the stream strengths and timings for the parts East of there. How's that for a plan? Any additions or recommendations?

[Alan Mighty]

Originally Posted by DefinitelyMe

plan is: turn up at the Eastern end (at the Bligh Entrance) at dawn one day and sail as fast as possible. Anchor at dusk and ask the nice Australian aeroplane people for forgiveness if they object.

I've been hoping someone else would comment on this. It's way above my station.

Reason being that I think asking for forgiveness from Aus officialdom gets you nowhere. As I've noted elsewhere on CF, my advice is to think of Aus border officials as German Shepherd dogs. Friendly when they feel comfortable. But they bite when they are frightened by something unusual
and if they think you are powerless and uncertain.

I've a vague memory of talking a year or 3 ago to a non-Aus cruiser who had e-mailed Aus Customs to give them the required advance notice of their intention to enter Aus at Thursday Island. I think that cruiser asked for and was given permission to anchor in Torres Strait before entry procedures on the basis that (1) Quebec was flown; (2) no attempt was made to go ashore; (3) no contact was made with any other person/boat; and (4) entry was made at Thursday Island as soon as possible.

I've read of the cases of several non-Aus cruisers who were taken to court in Aus by the predecessor of the Aus Dept of Home Affairs and convicted of not giving adequate advance notice of their entry to Aus, then fined not insignificant money. One cruiser had a good excuse: he had been informed at an Aus consulate that he did not need to give advance notice. The court case still went against him!

You can read those stories for yourself at: Australian Customs Report

I know the US skipper of a sister-ship to my Led Myne who, once he had accomplished exit procedures, was overflown several times and warned not to anchor in Aus waters. And on one of those overflights, the coastwatch aircraft calculated that he had travelled "too slowly" and aggressively asked if he had anchored in Aus waters and warned of the punitive consequences if he was found at anchor.

I also can assert - as have other CF members - that I have transited Torres Strait and entered Aus on occasions without being overflown by coast watch aircraft and without being interrogated by VHF as to my identity and intentions.

I'm aware of costs in money and your time of processing and paying for entry into Aus.

I've done it a few times and think that the small amount of money I paid as a bribe to an Indonesia official once was nothing compared to the gross bureaucratic insult that Aus forces on foreign cruisers visiting Aus.

I suggest that you time your passage through Torres Strait so you do not need to anchor.

Were you to decide to enter Aus, you can consider how much advance notice you need to give by considering the table:

https://www.homeaffairs.gov.au/trav/...w-youre-coming

[StuM]

Originally Posted by Alan Mighty

...
I suggest that you time your passage through Torres Strait so you do not need to anchor.

If your passage plan requires you to anchor, it shouldn't be a problem.

http://www.un.org/depts/los/conventi...clos/part2.htm


The United Nations Convention on the Law of the Sea:
Part 2 Territorial Sea and Contiguous Zone

SECTION 3. INNOCENT PASSAGE IN THE TERRITORIAL SEA
SUBSECTION A. RULES APPLICABLE TO ALL SHIPS



Article17

Right of innocent passage

Subject to this Convention, ships of all States, whether coastal or land-locked, enjoy the right of innocent passage through the territorial sea.

Article18

Meaning of passage

1. Passage means navigation through the territorial sea for the purpose of:

(a) traversing that sea without entering internal waters or calling at a roadstead or port facility outside internal waters; or

(b) proceeding to or from internal waters or a call at such roadstead or port facility.

2. Passage shall be continuous and expeditious. However, passage includes stopping and anchoring, but only in so far as the same are incidental to ordinary navigation or are rendered necessary by force majeure or distress or for the purpose of rendering assistance to persons, ships or aircraft in danger or distress.

[boatman61]

Going through non stop is no big deal.. its well marked with lights for night sailing.. the only real hazards are the tides but that can be dealt with easy enough with common sense..
I have found over the years my imagination regarding Capes, Straits etc around the world has always been a much hairier trip than the reality..
I would not recommend anchoring anywhere pre clearing in except in a real emergency.. they get pissey and its not worth the grief.. theres enuf as it is..

[Alan Mighty]

I reckon anyone who transits international straits should add to their library, right beside their copy of Cockroft, a copy of:

Ana G. Lopez Martin, International Straits: Concept, Classification, and Rules of Passage, Heidelberg: Springer, 2010.

Lopez Martin of course looks well beyond UNCLOS.

I've attached a fragment of p. 156 and all of p. 157. You should be able to read about your obligation to "proceed without delay" and to "refrain from any threat".

The later is used by states such as Aus to exercise sovereignty over "the waters of the strait ... and soil and subsoil".

Which can be (or is, when it suits them) read by Aus officials as giving them the right to rule "no anchoring unless we have expressly agreed to it beforehand".

[DefinitelyMe]

Wow! You guys really have an encyclopaedic knowledge of this stuff! OK, maybe not anchor....... we shall see. In other news.......... is anyone willing and able to give us a hand with the Indonesian Yacht Registration thing? Apparently you can have more that one yacht on an account, but of course it would probably involve a few emails and a bit of work on your part in that respect. Any takers for a fellow sea-gypsy? :-)