Scuba diver swept miles away from his boat off Rye in VIC. Is the LDS to blame?

3 weeks 4 days ago - 1 week 5 days ago #303688 by packo
packo created the topic: Scuba diver swept miles away from his boat off Rye in VIC. Is the LDS to blame?

I'm posting this serious incident in the "Hanging On The Deco Line" category rather than "Media Reported Incidents" because that is where I have previously put up a long string of posts warning of the possibility of this type of incident.

The scuba diver was found alive after a long helicopter search. In other circumstances there might have been a different ending. For those who have have struggled through my long rants with only a shoulder shrug, or worse, this is an example of the warning that boat diving offshore along the Sorrento to Rosebud stretch can be dangerous if done at the wrong time.

Unfortunately the Local Dive Shop has been recommending precisely "the wrong time" for several years on its website. A number of other (senior) and respected diving figures are also under the mistaken illusion that slack water along this stretch of coast is delayed by 2 - 3 hrs after slack water at the Heads. It isn't. Never was, and never can be.

There is bucket loads of evidence, both theoretical and observational, that the real slack delay is only in the order of 5 to 15 minutes, yet the dive shop persists with its stance - potentially endangering anyone who takes note.

This bad advice is spread across the internet via an article that has achieved quite a high google ranking so will appear in most search results for all manner of searches loosely related to currents and slack water in Port Phillip Bay.

Recently I saw it even achieve a google "featured snippet" status, giving it the top hit in the results screen PLUS a small extract collated (autonomously) by google itself. I have send google an "inappropriate (dangerous)" feedback on this, but others need to do the same to have any effect. (The google search string was "Port Phillip Bay tidal currents").
(Update 28/12/17: Thanks to google for being responsible and to any others who may also have reported this. It seems the offending article has now been demoted some distance down the results page and the "featured snippet" on this topic is now extracted from the Port Phillip Sea Pilots' webpage. That page of course tells the truth that slack water delays at inside sites are very small and can almost be ignored.)

(Update 03/01/18: Damn, looks like the "google demotion" lasted only until the end of 2017 and now I see the scubadoctor article with the bad advice is now back up at the top of that results page and again given "featured snippet" status. I'll try once more but some complaints from others are probably needed to remove it's "featured snippet" status.):(

Sure the offending article does now mention (after a lot of nagging) that the Port Authorities and Ship Pilots disagree with the advice given, but the article still leaves the impression that "big delays should be factored in" when diving 5km - 20km inside the Heads.

This is dangerous advice and urgently needs to be amended before a life is lost. This one was a very close call and involved quite some luck to produce a non-fatal outcome.

The incident was reported in last week's edition of the Southern Peninsula News as:

A SCUBA diver was lucky not to be washed out through The Rip in strong currents last week. The 51-year-old, of Springvale, was diving alone north of Rye pier when he got into trouble, 3.20pm, Thursday 14 December. The alarm was raised by a friend on the beach.

“The Police Air Wing soon found the dive boat with the diver flag still flying, but no sign of the diver,” Senior Constable Paul O’Reagan said.

“We were able to contact Peninsula Aero Club and confirm fuel was available, and were able to extend the search until the diver was found. He was a long, long way from his boat.”

The chopper directed a boat to rescue the diver at 6pm. Sergeant Michelle Bradley, of Rosebud police, said he was taken to Rosebud Hospital suffering mild hypothermia.

The aero club’s Ian Johnson said that, in the two months since the helicopter refuelling depot had been commissioned at Tyabb, two lives had been saved because the police were able to refuel and extend the range of their water searches.

( )

. . . and reported in the Geelong Addy as:

"THE eagle-eyed skipper of the Queenscliff Ferry has helped rescue a diver lost and adrift in the Bay on Thursday.

The Searoad Ferries skipper spotted the missing diver late Thursday afternoon, alerting search crews that had been looking for the missing diver for a number of hours.

Before the ferry could lift the diver on board, police arrived and plucked him from the water."

Forget the local rag's hype about being "lucky not to be washed out through The Rip" as that was never going to happen from his starting point because the ebb tide would turn again before he reached the Rip. Rather the real danger here was death by drowning due to exhaustion or hypothermia.

Sure some of you will jump on the fact he was diving alone from an anchored boat, but the prime cause of this near tragedy was his poor choice of dive timing at around 3 hours after slack water at the Heads - precisely when the local dive shop and the dangerous "very delayed slacks" myth both advise divers to dive in this area.

After a number of phone conversations with the police air wing, searoad ferries, and southern peninsula rescue personnel
this is the best I can do to piece together some details (the locations are a bit approximate):-

Date: Thursday 14th December 2017.
Timeframe: 2pm to 6pm.
High Tide Point Lonsdale: @ 9:04am.

BoM Rip Predictions: Slack after flood @ 11:35am, Max Ebb -4.75 knots @ 2:21pm
Packo Predictions: Rip_Slack @ 11:31am, Rye_Slack = Rip_Slack + 8 mins delay = 11:39am

Bad Local Dive Shop advice: Rye_Slack = BoM Rip_Slack + 2hrs 50mins = 2:25pm (cf Max Ebb stream above @ 2:21pm)

Dive Entry time: Approx 2pm (seems possible this bad choice was informed by "The Myth" saying slack expected around 2:20pm).

Dive Entry Point: Approx 4.5km north of Rye, about 1km short of the shipping channel. (Scalloping?)

Alarm raised: Approx 3pm - 3:20pm by friend at beach when diver failed to return

First Sighting: Police Helicopter spots diver (safety sausage was deployed) near channel marker #4 but then looses sight of him in "unpleasant choppy conditions" with 20 knot SSW wind and 0.5m waves.

Second Sighting: Sorrento ferry captain on normal route to Queenscliff, but running slower and keeping a good lookout at police request, spots him a little west of #2 Channel marker nearing 6pm.

Recovery: Ferry diverts for attempted recovery but in the end shelters the scene to allow a police boat pickup around 6pm. Diver still wearing tanks and weight belt. Totally exhausted and cold after around 4 hours in the water. Unable to swim the last one or two metres to the police boat and needed to be pulled in on a thrown line. Conveyed to Rosebud Hospital for treatment for mild hypothermia.

Total Drift Distance: around 10.5 km (5.7 nautical miles), average drift speed around 1.4 knots. Note Ebb slack due around 6:30pm so peak drift speeds probably around 2 knots. Tide cycle would be classed as "medium to big".


I have raised this issue with several senior level divers and the DIVA and SDFV organisations. So far the response is basically "a big yawn". (MSV see the danger but claim they can't act!)

Come on Guys, stop jerking me around as this is serious! Do you have to wait until someone actually DIES?

On the second attempt with DIVA the response I got was to the effect:
Most of us feel there is no issue and you have no current facts that state there where accidents related to the slack water etc.

I'll try DIVA for a third time now that there is a reported incident to refer to. Also some younger guns in DIVA do know the tides better, so there might be more of a will to behave properly this time around.

Hopefully the LDS concerned might read this post and beat us all to the punch by pulling the bad advice down before the Christmas holidays start in earnest!

The rescue guys told me of another diver incident some years earlier also starting off Rye but a bit closer in, and near the relocated and restored Sth Channel Pile Light. That diver was sucked out the Rye Channel by a strong Ebb tide and right across the main shipping channel to be rescued near channel marker #8. That was about a 4.5 km drift and again involved hours of expensive helicopter time, and multiple boats and personnel in the search.

So before we as divers manage to fritter away more taxpayer dollars, and the good will of the search and rescue folk, let us all learn from this misadventure and stop promoting ill informed and dangerous bullshit to one another.

cheers & merry Christmas,
Last Edit: 1 week 5 days ago by packo. Reason: googles reaction

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3 weeks 3 days ago #303689 by AB
AB replied the topic: Scuba diver swept miles away from his boat off Rye in VIC. Is the LDS to blame?
All due respect, but I don't see the timing of slack as being the issue in this incident. The scallop grounds off Rye are pretty shallow and you can spend way more than the practical slack water time on a dive. The issue I see is someone diving from an unattended boat. In areas where there may be current, there should always be a lookout on the boat, and the diver should always have a SMB (saw the footage from the ferry, no SMB sighted). This incident resembles that of a diver swept away from the Yongala a year or so ago. Same amount of lack of common sense. There is no evidence this recent diver had ever consulted the information from the LDS, and the belief about delayed slacks has been around forever. The common reason to dive in that area is to collect scallops, and it's best done as a drift so you can cover more ground. We've done this dive at slack water and you have to swim a fair way to get your bag. There are no underwater landmarks there, so getting lost is more than a likelihood. So even if he timed the slack correctly, the outcome was likely to be the same.

There are so many things which can go wrong that a person on the boat can remedy, but there seems to be a trend away from attended boats. Locally, RIBs which can only handle 2 or 3 divers are gaining popularity, so from the get go these divers are planning to regularly leave their boats unattended. It's a requirement when diving the Canberra to have boats attended at all times, but I have seen empty boats moored there. People just don't seem to see the added risk.


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3 weeks 3 days ago - 11 hours 4 minutes ago #303690 by packo
packo replied the topic: Scuba diver swept miles away from his boat off Rye in VIC. Is the LDS to blame?
Hi Alan,

In writing this response I did find myself agreeing with many of your points and conclusions, but not all.

It would be great to hear the diver's side of the story but not sure that will ever happen. The police were reluctant to even the idea of passing on my contact number to the diver.

Now to some thoughts on your reply:-

"(saw the footage from the ferry, no SMB sighted)." Well I guess video trumps eyewitness statements! Perhaps my search boat crew eyewitness was mistaken, or was talking about some other period during this long operation.

"This incident resembles that of a diver swept away from the Yongala a year or so ago." Agreed, but the difference was this one just involved incredibly good luck whereas the Yongala incident was a blooming miracle!

"There is no evidence this recent diver had ever consulted the information from the LDS" Agreed, none whatsoever! And many will see me hinting at the possibility it could have happened as a pretty cheap shot. Perhaps it was. It is hard to be completely detached from one's emotions.

However the high google rankings show many divers ARE consulting it. They may absorb the misinformation which could later land them in a dangerous situation. If you are personally comfortable that a popular industry player is promoting incorrect and dangerous info, and feels no need to check it when criticism surfaces, then I guess that is your call. I am struggling to think of another "adventure sport" realm in which this sort of thing would be allowed to continue.

The reasonable conclusion this was probably a scalloping adventure gone horribly wrong is largely irrelevant. The real point is that another diver, intent on doing a deliberate "stay put" slack water dive and using the LDS slack water advice to plan their dive timing, would also find themselves in the water at max current time (3 hrs after slack). They would then also find it nearly impossible to work their way back to the boat.

Your view might be, as many others have said (privately), that someone silly enough to hop in at that time without properly checking the current more or less deserves what they get. My own view is no matter how silly a diver might be, they simply don't deserve to be led into this sort of danger by an industry professional.

". . and the belief about delayed slacks has been around forever." Agreed. Around at least 50 years by my count. If your inference is that it is a largely harmless piece of nonsense that nobody pays much attention to anymore, then my experience is different. Time after time I have found that older divers who may have grown up with this myth still struggle hard to shake it off, and some never do reach that point. There is also the issue of interstate divers, or Vic divers new to this area, or even newbie divers - these groups can't be expected to have developed any immunity to the twaddle being presented.

If you take any assumed scalloping activity right out of the picture and look only at the dive timing, this incident graphically proves the danger element inherent in that myth. Surely about time we completely killed that dangerous view off don't you think? That is all I have been trying to do - and it shouldn't be such a difficult and lonely fight.

I originally thought this myth had already been killed off around the turn of the century, but was astonished to to find it alive and well in 2015 (and still in 2017!).

Many will perhaps feel I am unnecessarily putting the boot into this particular LDS but by any measure their response, or lack of, to this safety issue is simply indefensible from any perspective. I know it is not good for the industry but it needs to be aired. Numerous private discussions either achieved nothing or were cut short by the LDS owner. DIVA's response (so far) also sucks. It rather smacked of "mates protecting mates".

Again I have no problem with people hanging on to their own funny little ideas, provided those views don't compromise the safety of others outside their sphere. However to promote that type of thing widely on the web without bothering to conduct the appropriate testing when that advice is questioned is frankly an action I don't have much tolerance for. I am sure the LDS's public liability insurer would also be having a pink fit if they were aware of this situation.

"The common reason to dive in that area is to collect scallops, and it's best done as a drift so you can cover more ground." Agreed again. However if this really was a "slack aware" solo scallop diver, the sensible choice would be to drift for the hour or so prior to a slack. Then if you do manage to get lost, surfacing (at slack) to swim back to your anchored boat is easily achievable.

Don't forget this guy targeted exactly the max ebb flow time, and from an anchored and unattended boat. It smacks either of complete naivety, or of being grossly misinformed.

"So even if he timed the slack correctly, the outcome was likely to be the same." I disagree here. In this area there will be an hour or so either side of slack where a well motivated diver can make reasonable progress against the likely currents. However around the max current time, the chances of regaining the boat are much diminished as we saw in this case.

Regarding unattended boats - I have to agree that in this incident if it wasn't for his attendee (an astonishing 4km away on the beach) this diver would probably be "toast". Shows that at least for solo/unattended boat dives, letting someone know your expected time of return might save your skin.

Note however the second "lost diver" incident the search & rescue guy told me about was in fact from an attended boat. However he surfaced some distance away and was unable to make any progress back to the boat. Unfortunately he drifted out of visual range while still unable to attract the attention of those aboard the boat. Whistles are good!

Thanks for your reply Alan. It is good that other views are aired here. It encourages readers to think more about where they stand.

I'll try hard to make this my last post on this issue as it seems I've done about all I can do. I am obviously a lone voice on this topic and maybe a little out of step with many fellow divers. I only popped up again because DIVA was more or less saying "show us an incident or shut-up!"

cheers and safe diving,

Update 13/01/2018: In another thread that slipped into this issue Lloyd Borrett from Scuba Doctor noted that:
" packo wrote: the Scuba Doctor's advice on slack water times."
He then went on to say: "It's not The Scuba Doctor's advice. It's the advice published in books and widely held by many highly respected and experienced commercial and private divers."

Ok, the term "Scuba Doctor's advice" was shorthand for "the advice appearing on the Scuba Doctor website" (and just about nowhere else since the book is long out of print). In a few "conversations" with Peter Fear (the original "Scuba Doctor"), he made it pretty clear he supports that advice 100% plus. I am now fully aware that this view is held more widely than I first thought. I am a little shocked that the very first and rather clumsy post I made on this, "Stamping out the Bulldust", is now nudging 4,500 views. Obviously there are many divers and other southern bay users who seem to need their bulldust stamped out.

However Lloyd it seems among all the believers, you are the only one actively promoting this view to all and sundry via the web, so it is you I must target. You declined to name your other supporters so I was unable to tackle them about it.

I know you feel personally targeted even though there are many other believers, but it is your organisation that is doing most of the the damage by encouraging this old myth to live on. The fact that there are "highly respected and experienced commercial and private divers" who believe in this stuff doesn't make it "right" - rather it makes it all just a little bit sad.

Mankind escaped from the dark ages of witchcraft, superstition, voodoo and the like by coming to the conclusion that by adopting "evidence based belief systems", the world seemed to work much better and many more advances were made.

The problem with the "very delayed slacks" idea in this modern world is that it is simply an "evidence free belief system", handed down from various "high priests" and "cult figures" to the followers in a never-to-be-questioned manner.

It arose from confusion between tides (vertical water movement) and tidal streams (horizontal water movement). Many people thought these were so closely related that if tides were delayed in the south of the bay (perfectly true), then isn't it reasonable to assume streams are too?

Well no, it is not reasonable to assume this without any evidence whatsoever. No hard evidence can be found because it simply doesn't exist. All the supporters can manage to do in "arguing their case" is to talk about respected elders (high priests) and some experienced divers who preach that the slacks do suffer big delays as you move into the bay.

The correct relationship between tides and tidal streams is quite a tricky one. Both the relative strengths of these two water movements, and the timing between them, can be drastically transformed by various different combinations of above water geography and underwater depth profiles. Those interested in trying to get their heads around this might like to look at this link:-
The Relationship Between Tidal Streams and Tides

Why can't any of the very delayed slack high priests, or their ordinary rank and file followers, explain the workings of their belief such as:-

How water levels in the central and north bay areas fall shortly after a flood slack at the Heads while their "delayed flood stream" continues to push water northward past the likes of Mud Island and the South Channel Fort for several more hours.

Or how it is that 3 hours after that Rip slack, when their "chewing gum model" of southern bay waters has been "stretched out" by around 30% in length due to its ends being pulled apart in opposite directions, the "chewy" doesn't seem to get any thinner? (ie. a water depth decrease of around 30% would be expected).

The very delayed slack crowd simply cannot muster any explanation or evidence that their thinking is correct. They then try to "balance the ledger" by refusing to think about, or even look at, the truckloads of evidence presented by the other side to show that all areas of the Bay begin to either drain or fill in the same direction within no more than 20 minutes of the tidal stream reversing at the Heads.

The failure by both these men (and DIVA) to even look at the live streaming video evidence now available for Sorrento waters was a very low point indeed in this "debate".

Although the special "spar-bouy" has since been removed, on days with big tides and little wind, the "swing around" of the moored sailboats still gives a pretty clear cut signal of when the tide stream reverses at Sorrento. Here is an example which I captured from the live video yesterday:-

It wouldn't really hurt you to have a look at the live video feed would it? It might convince you I'm not making all this up and elaborately faking still photos. If you don't want to do it for me, then do it for your customers and website devotees!

One would have thought the recent "diver swept away" incident off Rye on the 14th of December 2017 would have been some sort of wake up call. It wasn't. All we got was a string of abuse of that diver because he didn't have the right equipment, or didn't follow various common safety rules.

None of those things had anything to do with the fact that for unknown reasons he was diving at maximum ebb current and was therefore unable to swim back to his boat. There was simply no "very delayed slack" that some think occurs off Rye three hours after the ebb tide outflow begins at the Heads. Certainly all of Lloyd's points would have helped him get out of trouble, but the only thing that got him into trouble was the bad timing.

The "very delay slack view" promotes those times as "the best time to dive" in this general area, so it must take its share of the blame as the primary trigger of this near tragedy.

With the exception of a religious belief, if one of your other belief systems isn't supported by any evidence at all, then it is time to chuck it out and adopt the one that is supported by all available evidence. That changeover seems to be going to take a very long time at both the Scuba Doctor businesses. In the meantime divers are being misinformed in a way that is dangerous.

Sure there will some small level of embarrassment that Scuba Doctor has promoted this myth for a while and then was forced to "flip over". However that will quickly be forgotten in the light of all the good things this business does. It is far less awkward to face the music now, rather than after the next incident that might just spiral downwards to a fatal outcome.

So in summary: Thanks heaps Scuba Doctor for the great VIC dive-site webpages - but no thanks at all for prolonging the life of a stupid slack water myth.


(I was going to post the above update as a new reply, to again elevate the issue to the top of the forums. However I'll give Lloyd a break and wait for a while to see if anything gets done. Hope nobody dies in the meantime!)
Last Edit: 11 hours 4 minutes ago by packo. Reason: URL update

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