Wreck Locations

9 months 2 weeks ago - 9 months 2 weeks ago #303259 by lloyd_borrett
lloyd_borrett replied the topic: Wreck Locations
G'day,

The old BSAC and even older VSAG lists are no more. Unfortunately, there was no easy way to put in redirections to the new list.

Maybe the latest GPS marks at https://www.scubadoctor.com.au/melbourne-dive-site-gps-marks.htm will start to rank better now.

Best regards, Lloyd Borrett.
Last Edit: 9 months 2 weeks ago by lloyd_borrett.

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9 months 2 weeks ago #303260 by james
james replied the topic: Wreck Locations
Sounds like a great project for one of the clubs to go out and confirm the locations of the wrecks. We did this down in Tassie for our much smaller wreck grave yard, was a great much worthwhile exercise .

It is very frustrating having uncertain or inaccurate GPS marks for a wreck.

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9 months 2 weeks ago - 9 months 2 weeks ago #303261 by packo
packo replied the topic: Wreck Locations
Thanks to Lloyd for the swift action is disabling the old VSAG & BSAC GPS lists. However without a redirection to his new site some people may now want my blood! Couldn't you pop in a link or at least a "copy & pasteable" plain text URL? You may not wish to do that for ethical reasons and I do understand that.

Your action has partly solved the problem except that although those lists are now disabled, the "google synopsis" of the hit will often still carry the bad coords. I guess the only hope is that over time these will slip down the rankings.

A final fix-up task is for you to correct the Longitude to 53 mins in " www.borrett.id.au/divelog/divesite.php?id=31 ".

That is currently the top hit in a google "rosebud reef coordinates" search and it has been "ghostnetting divers" for far too many years.

Page one of those google results is just so depressing!

Hit #1 www.borrett.id.au/divelog/divesite.php?id=31 - crap Longitude
Hit #2 "diveboard.com" - crap Latitude
Hit #3 is the now disabled VSAG list - but the bad coords still show in the "synopsis text".
Hit #5 is a fishing GPS list - also with crap coords.
Hit #7 also a fishing GPS list/map. Couldn't find Rosebud Reef on their nice map but gave up when I noticed Rye Boat Ramp pinned as being in the middle of the bay (Real Lat of 38d 22 min entered as 38d 2.2 min). Sigh!

Maybe the "List Makers" should refuse to add any new site unless they get at least 3 independent sets of GPS coords that fall within 10m of one another? I don't know what else to suggest, it is a mess of our own making. It is not exactly rocket science BUT DOES NEED CARE!

By the way if you are not familiar with GPS sensitivities, well here in Vic we have:

0.001 minute Lat shift = N-S move of 1.85m (or roughly 2m)
0.001 minute Long shift = E-W move of 1.85x(CosLat) = 1.53m (or roughly 1.5m)

So distance in metres between two GPS sets where the Lat & Long differences are in units of 0.001 mins is given by:

Square Root of [ (Lat_Diff x 1.85)2 + (Long_Diff x 1.53)2 ]

If you prefer to work in decimal fractions of a degree - then see a psychologist!

So in mediocre vis you need to put the pick down within +/- 0.005 mins of the right spot for both Lat & Long to be sure to find your target.
cheers,
packo
Last Edit: 9 months 2 weeks ago by packo.

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9 months 2 weeks ago #303263 by james
james replied the topic: Wreck Locations
Another bit of information that should always accompany GPS marks is an accurate depth of the wreck. If there is any doubt about the marks knowing the depth can be very helpful.

So in mediocre vis you need to put the pick down within +/- 0.005 mins of the right spot for both Lat & Long to be sure to find your target.


I very rarely place the shot directly on the GPS mark, I use the GPS mark to get me to the wreck and then use the sounder to pick the spot I want to place the shot line using the sounder.

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9 months 2 weeks ago #303264 by packo
packo replied the topic: Wreck Locations
Hi James,

I guess its different strokes for different folks. By "target" I didn't necessarily mean "wreck", but an anchoring target or shot target at a convenient point alongside the wreck.

Initially I usually put a lot of effort into getting good GPS data for most of the site, then often don't even bother switching the sounder on for subsequent visits. Maybe that's more of a reflection of my ageing and low-tech (flasher) sounder.

For most wrecks I visit I have programmed up my GPS chart-plotter to paint an outline of the wreck. So in general at "max-zoom" I can doodle around this outline (without sounder) and plant the pick near whatever part takes my fancy for that particular dive. Seems to work ok for me.

I guess that is really pretty much how you are using your sounder - same approach, but just different tech to get you where you want to be.
cheers,
packo

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9 months 2 weeks ago - 9 months 2 weeks ago #303265 by peter6956
peter6956 replied the topic: Wreck Locations
Packo,

Yes agree, I know on wrecksite some of the coordinates put the wrecks on shore, one in particular near San Remo would have had to be lifted up onto a cliff top (must have been a very big sea).

James,

Yep agree depth is always helpful as well.

Anyone help with advice per my last post re contacting authorities to check shipping?

I am new at using a quality sounder/plotter for locating wrecks. To date I have always chartered dives so sat back and let others have all the worry of being spot on. Nothing like having an angry diver complaining that you are not on the wreck to get you very interested in being more accurate. My previous boat was a medium tinny with a basic fish sounder.
Last Edit: 9 months 2 weeks ago by peter6956.

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9 months 2 weeks ago #303266 by lloyd_borrett
lloyd_borrett replied the topic: Wreck Locations

james wrote: Sounds like a great project for one of the clubs to go out and confirm the locations of the wrecks. We did this down in Tassie for our much smaller wreck grave yard, was a great much worthwhile exercise . It is very frustrating having uncertain or inaccurate GPS marks for a wreck.


Actually many boat owners in various local dive clubs have GPS marks that they use regularly and thus are known to be accurate. Over the years I've made numerous requests for them. But most don't provide them, because I have a reputation for publishing the marks for all to have access to.

Thus we have the situation we have. I publish what I can, but often have no way of knowing how accurate the marks provided are.

The irony is that some of the clubs also have the inaccurate marks and regularly get them mixed up with the accurate ones and thus have problems locating the dive site. Go figure!

I'd like to enhance my GPS marks database by adding the ability to record and show more information about the dive sites, plus better providence for the GPS marks. Anyone like to help?

Best regards, Lloyd Borrett.

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9 months 2 weeks ago #303267 by Stan Bugg
Stan Bugg replied the topic: Wreck Locations
Mark Ryan convened a meeting back an 2005 or thereabouts.....my memory is hazy....to share GPS for graveyard wrecks. Among attendees were Brian Cornell, Bob Wealthy, Jeff Giddens of Scuttlebutt charters, and several others who's names have been forgotten.
Mark was trying to address the same issue that is being discussed here; the wide variety of "correct" GPS for the deeper wrecks off Torquay.
Attendees agreed to pool their knowledge, albeit reluctantly in some cases.
Not surprisingly the data revealed striking differences between individuals and groups...but....all regular visitors to these wrecks were able to find their targets regularly.

The last point would suggest that pinpoint accuracy to a metre or less (!!) is less important than familiarity with the processes, and a degree of experience out on the open water.

Using a combination of info ....GPS, sounder, and....dare I say it....transits....are all part of the adventure.

Before you poo-poo transits, what could possibly go wrong??? ...except the day on the Courier when the fog was so thick we could hardly see 50m.....or the transits for the McPherson that were lost in a bushfire......or one of my Eliza Ramsden transits disappearing when they chopped a tree down at Queenscliff!!!

Regards,
Stan

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9 months 2 weeks ago #303268 by peter6956
peter6956 replied the topic: Wreck Locations
Lloyd don't mind helping where I can

Yes it's so sad that others have to have a power trip by withholding information.

Guess I am from the new gps/plotter era and just getting a handle on my new Garmin plotter/sounder, guess it will take some getting used to, to read the bottom.

I have noted on some of the larger wrecks the different positions often appear to be at different ends of the wreck site and suspect that this is often the case where as others have said, different positions but everyone finds the wreck.

When we attempted to find Elisa ramsden we found a reef just north if it instead. In talking to others who have dived it, their comment was yep know that reef if we got that we knew where to go to find the wreck. Local knowledge is good.

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9 months 2 weeks ago #303269 by AB
AB replied the topic: Wreck Locations
Stan, or the time I was heading out to the Courier, and three F18's were doing runs up and down the coast, and my satellites all dropped out!! Thankfully it was clear enough to see the transits and we found our site! Re the use of a sounder, it is recommended to slowly traverse the wreck and drop the shot after you clear it so your big lump of lead doesn't damage these fragile sites.

Alan

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9 months 2 weeks ago - 4 months 1 week ago #303270 by packo
packo replied the topic: Wreck Locations
Although this thread seems to have run its course, I want to add a few more points on sounder vs GPS positioning, and also highlight two thread requests that went unanswered.

I received a bit of stick over revealing that where I had previously well sussed out a wreck site via GPS+Sounder, I sometimes chose to anchor alongside it on subsequent visits using GPS numbers alone.

At least for small dive boats like mine, I would maintain that defining the perimeter of a wreck site with GPS+Sounder in perfect conditions of no waves or swell will yield GPS data that is as good as, or better than, sounder positioning on a day with wind waves and swell. If you are over 30m depth, pitching and rolling by +/- 15 degrees or more will have the sounder beam swinging around over a 20m path on the bottom.

Sure most sounders will have a beam width wide enough to still return a solid bottom echo from "straight down", but the highest sensitivity spot important for detecting the weaker echos from various parts of the wreck will still be swishing about over quite a distance near the seabed.

Other issues in sounder vs GPS for accurate re-location are:-
1) Many boats are set up with a horizontal separation of around 4m between sounder transducer and the GPS antenna (internal or external). This means surveying a pinpoint target may give you up to an 8m offset between GPS and sounder readings depending on your approach direction. Although a little inconvenient my GPS receiving head is mounted within 1m of the sounder transducer.

2) The above problem can be compounded where the sounder transducer face is aligned with the boat's slipstream to give good performance at speed. When the boat drops off the plane to "survey speed" the hull's trim can drop a dozen degrees, throwing the sounder "sweet spot" even further aft of the GPS antenna.

Now for the two requests that have yet to get a response. Interstate readers might want to "click out" here.

1) I previously wrote (for Lloyd Borrett):

A final fix-up task is for you to correct the Longitude to 53 mins in " www.borrett.id.au/divelog/divesite.php?id=31 ".

That is currently the top hit in a google "rosebud reef coordinates" search and it has been "ghostnetting divers" for far too many years.


Although Lloyd was quick to disable other misleading sites, this one appears to have fallen off the list. Please Lloyd just a couple of keystrokes can fix this and may save others some heartache.

2) Peter6956 previously wrote:

Anyone help with advice per my last post re contacting authorities to check shipping?

I can't answer this but am interested in the situation as lots of diving near the Heads seems to be in a legal grey area with an unfortunate past, a murky present, and an uncertain future. My take on the history is:

Back in 1982/3(?) some ragbag divers anchored in the south channel forced a ship off course and it nudged a sandbank. Port authorities reacted with "port rule xx" (can't remember the number 42a?). This declared a whole swag of the Heads area as a "no anchoring zone" with stiff penalties.

Since it was pre-GPS, the boundaries were defined by compass bearings from fixed channel markers and the prominent land points of "Rock Beacon" (Pt Nepean) and "Ball Beacon" (Shortland Bluff). This was a ridiculously large "fairway area" but was necessarily so at the time because of the limited technology rec boaters had for knowing if they were transgressing or not.

Divers reacted by inventing "live-boats" where you didn't anchor but placed a "shot" at which you dropped divers off. This went on for a number of years but then the Harbour Master turned the "no anchoring" zone into a "no operational or recreational diving zone" unless written permission was obtained from the Harbour Master".

The charter companies got the appropriate "permits", and for a while there was a time where certain sites were restricted to "boats with permits". These also had to meet certain conditions regarding crewing, VHF radio watch, etc.

In more recent years things may have relaxed a little as sections 2.14 & 2.17 of the Harbour Masters Directions just now say "HM permission" and mention the conditions as only applying to "operational diving" (as distinct from recreational diving). They also seem to have dropped the prohibition on night diving within the zone.

I think now private boat divers have adopted the practice of getting a shipping clearance and seeking "permission for recreational diving within the zone" from Lonsdale VTS officers via phone or VHF. Whether VTS officers are actually entitled to give it or not is unclear, but that seems to be accepted practice. You can use marrinetraffic.com to see expected shipping traffic to see if it is even worth asking for "clearance".

With the closure of the West channel to commercial ships around 2005, the zone was modified. An area off Queenscliff was excised, and the border from the #1 channel marker to Pt Nepean was "bent" in a few places, seemingly to exclude the Eliza Ramsden wreck from the zone. This was a welcome change. The seaward edge was also slightly redefined into an arc rather than the original straight line. According to the charts the new definition also brought the Lonsdale Wall slightly closer to the edge of the zone but still on the wrong side of it - by as little as 20m in some places!

However the redefinition of the zone was never notified in a notice to mariners. It just appeared on a new chart edition. I tried to get the coordinates for the new definition from the Australian Hydrographic Office, but came up with a blank. The guys there said they just used "a sketch from PoMC" to draw up the new area. All seems very unsatisfactory to me! For solo divers and those also needing to anchor, these are important issues.

Technically the "no anchoring" (and also "no diving" without permission) zone does not take effect in Marine National Parks unless the relevant Minister has agreed to this. I haven't been able to determine whether or not this happened - and am afraid to ask! The advice from parks rangers is the slightly vague "yes you can anchor in the park - but don't anchor in the ship channel". I choose to interpret that as meaning the "defined ship channels" rather than the "defined no anchoring zone".

I had hoped the CDP project would have resolved this - as it promised to "extend the declaration of the south channel out through the Heads". No such luck. The port managers seem to want it both ways - leave an excessive old "fairway" declaration in place, but also define a ship channel through that area. Seems greedy to me to have a "no anchoring" channel running through a much larger "no anchoring fairway".

With GPS now accepted as a way to define rule boundaries, I would have thought there was scope to redefine the "no anchoring zone" to something a little more sensible - and give the solo or small boat divers a bit of a break.

So technically as it stands today, if you helicoptered your boat onto the top of the highest part of the Pt Nepean Reef around 4m above sea level, you could be heavily fined because you were a danger to shipping! (Maybe if you didn't have the anchor out you could get off on the technicality that you were merely "drifting"?).

Obviously all the surfers who anchor their boats off Pt Nepean are never moved on by the port "patrol boats", but what about other fringe areas like off Shorthand Bluff?

Seems like the port authorities are using a common sense approach and turning half a blind eye to this regulation, but I suspect their attitude differs between the "live boat" and the "must anchor" crowd. It is painful to recall this messy situation was brought on by some thoughtless divers all those years ago.

What are the views of others as to what you can and can't "get away with" and what might land you in trouble? Also what advice to Peter6956 (who sounds like a bit "solo diver" to me?).
cheers,
packo
Last Edit: 4 months 1 week ago by packo. Reason: colour adjust

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9 months 2 weeks ago #303271 by peter6956
peter6956 replied the topic: Wreck Locations
Packo

Thanks for the history lesson on the shipping issue. At least I have some understanding of where we are at now to some degree and how it got there.

Nope not a solo diver, I value my life far too much to go out on my own, anchor up and leave a perfectly good boat in the hope of finding it again. I only dive with someone on the boat who is capable, and don't normally do solo dives unless unfouling an anchor or down line. Mainly I dive on a down line from a float rather than anchoring mainly due to depth. More often than not I have dived from charter boats, but given the demise of DV I now chose to upgrade my boat to something usable for diving, so all those things done by the charter operator I now have to do, hence the many questions.

How much easier it is to pay a charter op to do all the hard work!

I prefer to find out as much as I can before setting off rather than making it up along the way.

Peter

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9 months 2 weeks ago - 9 months 2 weeks ago #303272 by peter6956
peter6956 replied the topic: Wreck Locations
Packo

Seeing I am a "bit of a solo diver", perhaps the correct response to that actually was "which part of me is a solo diver, so I can determine which of the rest of me is communal property?

Tongue in cheek?
Last Edit: 9 months 2 weeks ago by peter6956.

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9 months 2 weeks ago #303274 by packo
packo replied the topic: Wreck Locations
Thanks to Lloyd for the coord fix, and apologies to Peter6956 for raising the "solo diver" as a possibility. Only did so because if true could significantly affect the answers you might get from others about the VTS protocols for getting "shipping clearance".
cheers,
packo

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9 months 2 weeks ago #303277 by peter6956
peter6956 replied the topic: Wreck Locations
Packo

No need to apologise it's a fair question, and we are all big boys here. Better to ask and find out than assume and be wrong?

Peter

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9 months 2 weeks ago #303279 by AB
AB replied the topic: Wreck Locations
Peter,
The accepted method to check for shipping is to go to VHF ch12, wait for a gap in chatter between pilots and ships, and call "Lonsdale VTS", and give your vessel name. VTS will respond, usually asking you to switch to ch13. Once you have established contact, nicely ask the operator for shipping movements through the heads, for the period you are considering diving in the defined channel area, or close to the transit between the pilot boarding station, and the shipping leads at the Rip. The operator will read out to you the times and names of the ships. write that down. If you miss a time, or direction relayed to you, ask them to repeat. Remember to thank the operator!

The general idea is that you must not impede shipping, so you must be clear of the site 1 hour before the ship is due to transit. There used to be a 1 hour restriction after a ship has transited, but it was seen as of no benefit, so, once a ship has safely cleared your intended site, you may drop your shot and dive. Remember that the channels are a no anchoring area.

We tend to radio VTS, and make our plans around the times we are given. We only advise VTS where we are diving if our departure time is getting close to the hour clearance required, then we will also advise the time we will be clear of the site. So we don't actually ask for 'clearance' and this has worked fine for decades. Be aware that VTS will only give you the times for ships requiring pilots. Ships, which don't require pilots include the Tassie ferries, a half dozen local ships which have exemptions, and any military vessel. You must not impede these either! So you need to check the ferry sailing times, and maintain a watch for other ships. Live Ships AIS is helpful, but military vessels don't have AIS.

In case you do spot a ship approaching while you have divers down, you need an effective diver recall system. We use a series of three revs of the outboard directly over our divers bubbles. This means you don't have divers spread all over the place, and the divers know what to do when they hear the signal. You should give the diver recall in plenty of time for the divers to safely ascend and be picked up by the dive boat, well before the ship arrives. Divers, on hearing the three revs, start their safe ascent at the usual rate, but don't do a safety stop. If you can, recover the shot line before the ship arrives, but don't impede the ship!

Remember, it is your responsibility to keep watch, even if VTS gives you the wrong information (and they have on a number of occasions) so if you don't have your procedures down, don't dive in the channels area.

All this information, plus much more, is passed on in clubs. I strongly recommend you join either Getunder Dive Club, or VSAG to tap into the awesome resources available, and also get access to dives you would otherwise struggle to get to.

Alan

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9 months 2 weeks ago #303280 by AB
AB replied the topic: Wreck Locations
Some of my marks for Graveyard wrecks come from a list I stumbled on over a decade ago from a gov't department listing all scuttled wrecks in Australia. As previously mentioned, the gps marks were an unknown for accuracy, but the Victorian section had a number of marks verified by Rowan Stevens of Red October graveyard mapping project. I have used a few of these marks and found them to be accurate. Now Rowan is one who firmly believes in not handing out marks to anybody he doesn't know,

I can't find that data on my computer, and haven't found it on google searches, but I know it's out there! If someone can find it and post a link it would be helpful!

Alan

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9 months 1 week ago #303281 by peter6956
peter6956 replied the topic: Wreck Locations
Alan,

Thank you very much for the information and advice. It will be used with care. At this stage I am just gathering data and doing some preliminary exploration trips to validate the data. Then I can do some dives on the safer options before venturing into others of significant depth or risk.

Unfortunately I am in Gippsland so being a member of either club is a difficult exercise getting to the monthly meetings. Its about 1.5 hr trip each way, and a pity as otherwise I would consider joining, but something I will give some thought to regardless. I would appreciate and enjoy discussing with others the issues as well as normal diving discussions as well. Certainly good for me and I would hope I could add value as well in some way.

Regards

Peter

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9 months 1 week ago #303282 by peter6956
peter6956 replied the topic: Wreck Locations
Anyone know if the vicshipwrecks site is still current? I sent an email to Rowan via but it was rejected?

On that note I see on the site a number of positions on recreational wrecks, is it WGS84

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9 months 1 week ago #303283 by AB
AB replied the topic: Wreck Locations
Peter,
The Vicshipwrecks site is still up www.vicshipwrecks.com/index.php , but Rowan has disabled many of the pages.

Many of the members of my club, Getunder, come from places like Pakenham, Baxter, and even Moe. I am at Queenscliff. They don't always get to the meetings, missing some awesome guest speakers, but come diving with us. We have a strong technical side to our membership, diving graveyard wrecks most weekends and also getting to the TSS Kanowna and SS Queensland at times. You have to be invited to the really deep and 'special' sites, and that comes from doing your time in the graveyard. The best way to learn is to go with the guys who have been doing it for years. Clubs also make it possible to do those wrecks away from services, and where you need 10 divers to make the plan work, like at the Prom. I've done more than 40 trips to the Prom, which was only possible being a member of a club. This is a video we shot on the SS Gulf of Carpetaria vimeo.com/145239883 and of club diving at the Prom vimeo.com/53147414 so you can see what it takes.

Alan

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9 months 1 week ago #303284 by peter6956
peter6956 replied the topic: Wreck Locations
Alan,

A very pretty wreck. I was told the SS Gulf of Carpentaria was at 70m so a bit of a suprise for me. Where did you put in to go to her? Welshpool? I would not be able to do a beach launch with my boat, but I know many go out from Tidal River.

Yes I am tending towards joining your club. have sent an email to the President so see what I get in return?

Regards

Peter
The following user(s) said Thank You: AB

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9 months 1 week ago #303285 by AB
AB replied the topic: Wreck Locations
We always launch at Tidal River, as you can see on the second video. Yes, as few get to dive the Prom wrecks, they confuse the details. The other wreck visited is the SS Cambridge in 67 metres. I don't dive that as I'm a Low Tech diver, air only, but the images I've seen put it up there with the best Truk wrecks! I see no reason your boat couldn't be beach launched as it is similar to others we launch at Tidal. Just needs to be set up properly and have enough bods to push ( hence the club!)

Hope to see you at a club meeting or on a club dive soon!

Alan

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9 months 1 day ago #303341 by lloyd_borrett
lloyd_borrett replied the topic: Wreck Locations
G'day,

Over recent weeks I've made a number of additions, corrections and enhancements to the information on the Melbourne Wreck Dives page at https://www.scubadoctor.com.au/melbourne-wreck-dives.htm . It's a slow and tedious process and the information sources often conflict.

Eventually the goal is to do the same for Boat Dives, Wall Dives and Drift Dives.

You can also now see when the dive site mark was last updated for each site on the Melbourne Dive Site GPS Marks page at https://www.scubadoctor.com.au/melbourne-dive-site-gps-marks.htm .

Best regards, Lloyd Borrett.
The following user(s) said Thank You: packo, peter6956

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9 months 21 hours ago #303342 by peter6956
peter6956 replied the topic: Wreck Locations
Thanks Lloyd, more data for the mill

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8 months 4 weeks ago - 7 months 5 days ago #303354 by packo
packo replied the topic: Wreck Locations
Many thanks to Lloyd for all that extra work on the Scuba Doctor dive site GPS list.
He wrote: It's a slow and tedious process . .

I can well imagine that cos it is such an extensive list! The commitment you are putting into this is creating an excellent resource for VIC divers. Many are very grateful to you for all this good work.

The "last coordinate update" timestamp is also a welcome initiative. The previous "default" 2007 timestamp was sometimes confusing. You might want to tweak the Lady Cheryl date as it currently predates her sinking by around 5 years! (Maybe use 24/3/2012 - the date she foundered.)

Another tweak might be the Eliza Ramsden's position. I think the coords given were for the outer end of that magnificent thrusting bowsprit (and the shallowest part). Unfortunately several years back the bowsprit got bent over backwards in a rather extraordinary way.

PoMC reported in a notice to mariners that she had "rolled over" - their only way of explaining a decrease in minimum depth due to a "collapsing wreck". The now skyward pointing bowsprit is rather weird!

The given coords may now be over deep water too far forward of the bow. Perhaps the Longitude number might be nudged upwards by around 0.005 to 0.010 minutes so people don't miss her. (Peter6956 mentioned some difficulty in finding her.)

Final point is to fix-up the "Rye Scallop Drift" position. As mention earlier in the thread that position is several miles north of Rosebud, and within the shipping channel turning circle. It is a dangerous place to be, probably dredged free of scallops anyhow, and will only serve to piss off the authorities if people dive there.
cheers,
packo
Last Edit: 7 months 5 days ago by packo.

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8 months 1 week ago - 8 months 1 week ago #303408 by peter6956
peter6956 replied the topic: Wreck Locations
Lloyd,

For your info

Lady Cheryl S 38 17.934 E 144 39.238 the anchor was down the side of the ship, so within 5m

Hurricane S 38 20.474 E 144 52.309 and that was smack in the centre of the keel so within 5m

Both WGS 84

Peter
Last Edit: 8 months 1 week ago by peter6956.

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8 months 5 days ago - 8 months 5 days ago #303431 by packo
packo replied the topic: Wreck Locations
Peter,

I see you have begun your "dive all wrecks and verify" project. Thanks for feeding back the info to Lloyd & other readers. However what is he supposed to do with positions that are just a few meters different from the ones already in his list?

I think with GPS marks for wrecks, it is time to raise the bar a notch with more effort into establishing "how she lies" rater than just "where she lies". I'll get back to that point in a moment but first a little nostalgic waffle.

Without doubt GPS was a great development in many aspects of scuba diving and boating. It allowed easy sharing of dive site info. Although as we saw earlier in the thread, this needs to be done VERY CAREFULLY to avoid simple human errors spreading widely over the internet.

However lets just pause a while and think about what has been lost with the coming of GPS. As Stan mentioned earlier in this thread, no one should "poo-poo" the older (and probably ancient) visual transit method. Apart from being vulnerable to landscape changes and fog/haze issues, it does have several upsides compared to today's GPS.

Properly chosen visual transits can be much more accurate than "retail GPS" when within a few miles of the coast. Importantly they also gave the skipper continuous and instantaneous feedback rather than just updates every one or two seconds.

Combined with an audible depth alarm on the sounder, the skipper could do "eyes up" navigation and in general was better connected to the boat's orientation and heading compared to what one gets from a sequence of numbers.

Plotters do help a lot, but you are still rather too much connected to the screen rather than the placement of the boat in the immediate environment.

As mentioned earlier in the thread my pre-GPS diving used "horizontal sextant" angles for finding dive sites. It was sort of a "transit" method but with more flexibility. One advantage was that with a lot pounding on a pocket calculator it was possible to pre-calculate a "plotting sheet" on which you could mark both known sites, and sites you were keen to explore.

This mesh of intersecting "constant angle" lines on the plotting sheet was a series of arcs, each with a slightly different radius and centre point. These "plotting sheets" were extremely painful and time consuming to produce, but very handy to use. It liberated me from the usual constraints of the normal "zero angle" visual transits.

In my opinion the much simpler rectangular plotting sheets for today's GPS numbers should be used more often when "trading GPS marks". When the outline of a wreck or bommie is marked up in this way it makes finding and diving the site so much easier. Sometimes for shallower wrecks an aerial photo with GPS grid overlay can be used.

Shown below is one I found for the Hurricane wreck in southern Port Phillip Bay. The wreck (in 11m) shows as just a faint shadow, but over-plotting this with prominent points around the wreck site is immediately helpful.



For some years its orientation was confusing as the Heritage Vic site sketch showed a West(bow) - East(stern) alignment. This didn't seem to fit properly with the current flow across the wreck. The picture & GPS points show it is in fact NW to SE aligned, (with bow SE?). Still not certain which end is which - can anyone help out here? ( I'm just curious - not really "into archeology" and perhaps more interested in wrecks as habitat.)

I've created some GPS plotting sheets for some other local wrecks to show people what I'm talking about:



No great accuracy is claimed here, but even these rough polygon outlines are useful when approaching and anchoring up alongside a wreck (or reef). Although these are also programmed into my plotter, the paper versions are still useful for pre-dive orientation for divers new to the wreck. The sheets also allow the marks from other divers to be plotted to easily show if the "spread" of marks are due to typo errors, lazy measurements, or just that each group has marks for different points on the same wreck. My rough Coogee outline is here (bow NE):-



I usually fill in the axis numbers by hand, but used a computer for these ones as my handwriting is rather crappy. Although I use the big "stretched digits" only for the whole minutes, this could also be done for the first two decimals places to lessen the mark-up effort. However I generally fill in all the decimal places individually as shown, because I find it is then quicker to plot GPS points while at sea.

If anyone is interested in trying out this style of plotting sheet, the skeleton jpegs can be found at these links:-
GPS Plotting Sheet for Melbourne Divers

GPS Plotting Sheet for Divers in Other States

The plotting sheet for the interstate guys has the scale bar flipped around to a N-S orientation because the N-S scaling is the same for all Latitudes. If you want the E-W scaling to be the same, there are instructions on how much the image has to be stretched or compressed in the E-W direction for correct scaling near other major cities. This can be done in most image processing software or on a photocopier.

It is best to start plotting near the most southwestern part of the wreck which will give points nearest the plot origin. From there you can work around to the North and East. I've chosen the size to suit smaller wrecks/reefs and show all 3 decimal places of a minute for quick and easy plotting.

I was going to produce a sheet suitable for the bigger wrecks. However speed and ease of plotting is such an important point that in the end I thought just letting big wrecks overflow onto a second sheet is the best thing to do.

Not sure if Lloyd can incorporate any "wreck outline" info into the website, but maybe thee GPS plotting sheets can help quickly resolve those "one wreck - many GPS marks" situations. They are also handy on days where multiple boats and a multitude of divers turn up at the same wreck.

So Peter, if you have the time and inclination, adding a few outline points for each wreck you visit would expand the knowledge base in a pretty useful way.

You can either carefully note where the shot-line goes down and see what part of the wreck is closest to the lead when you hit bottom. Alternatively shifting the shot to a prominent point and measuring its GPS on it recovery is probably more useful. Can often do both in the one dive. Note that in deep water both steps need a lot of care to ensure the GPS numbers are for a point directly above the shot lead.

cheers,
packo
Last Edit: 8 months 5 days ago by packo.

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8 months 5 days ago #303432 by Stan Bugg
Stan Bugg replied the topic: Wreck Locations
With regard to which end of the Hurricane is which:
Maritime Archealogists Survey identified hawse pipes, winch and capstan at the north west end, which would strongly suggest that end is the bow. The VAS plinth is therefore close to the stern.
Regards,
Stan

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8 months 5 days ago #303433 by peter6956
peter6956 replied the topic: Wreck Locations
Packo

Appreciate your thoughts and will see what I can do with future info. With regard to the current info, it was simply a means of confirming to Lloyd that the data he had was either accurate and keep, or not and thus junk. i figure if you get a couple of independently taken shots and they are very close then one can say with some authority that the position is accurate, and thus post with some certainty, as distinct from "john said that Frank said that the port of Melbourne shots are XYZ and are accurate (I think)". I don't like posting data unless I believe it is accurate, if unknown and not verified by reliable people or independently verified, I would prefer not to post or at least post with a warning.

I am still coming to terms with my sounder as my previous one was simplistic at best and really only a bottom sounder. Until I get it sorted (and perhaps going to the Melb boat show I can get some more advice from the supplier), best I can do is position on the wreck. Yes understand and appreciate that at some 60m with current the buoy may be quite some distance from the wreck and needs to be accounted for.

With regard to your thoughts on sightings etc, unfortunately I think you will be hard pressed to convince the majority given the age of high tech and need for electronics with shiny bits on them that apparently do all the work. One of my hobbies is woodwork, and I use and love hand tools as it gives great control of the product, but not many places would bother with a hand tool now let alone how to use one or care for them. How many people can use a sextant, optical theodolite or even something as simple as a chart, parallel rule etc? Perhaps we are a dying breed, anything manual or non electronic seems doomed unless written down.

Anyway, have taken on board your thoughts, thanks.

Peter

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8 months 3 days ago - 4 months 1 week ago #303436 by packo
packo replied the topic: Wreck Locations
Stan wrote:
"With regard to which end of the Hurricane is which:
Maritime Archeologists Survey identified hawser pipes, winch and capstan at the north west end, which would strongly suggest that end is the bow. The VAS plinth is therefore close to the stern."


Thanks for that advice Stan, but I'm still confused over the plinth you call the "VAS one". Did find my local library (Mornington Peninsula Shire) does have a copy of the out of print book you referred to earlier ("Victoria's Ship's Graveyard" - Ryan, Taylor & Whitmore). Probably Peter6956 could arrange an inter-library loan to his local area if interested.

Its Hurricane site sketch seems similar to the Heritage Vic "Dive information Sheet", which I am still struggling to reconcile with what I see on the sea floor - two concrete plinths, one each end, and both on the east side of the wreck.

The image and my failed attempts to clarify bow from stern are shown below. Interested readers may need to reduce the width of their desktop browser window to force the left page panel to disappear and allow the page to re-render the complete image at full res (921x950). This makes the text easier to read.


Update: Don't think the above is the right explanation anymore. Key to the mystery seems to be that the original plinth in the top sketch was dragged out of position and across the wreck. So its new position was responsible for my confusion over which end is bow and which stern. See update in the next post below.

Peter,
Good luck with your new integrated sounder/plotter. At the boat show today I learned most of the newer units can "create their own chartlets complete with depth contours" and in real time as you simply steam back and forth across the site. Hope yours is one of those! No need for paper GPS plotting sheets then!

I hope to head in that direction with my own gear by re-engineering some of my old electronics and software. Probably a task akin to turning a pigs ear into a silk purse - but can't justify the big bucks for new gear in a small boat that ships more than its fair share of salt spray.

My nostalgic rambling about the "old methods" wasn't trying to promote or resurrect them. Hell no, I wouldn't want to go back to pre-GPS! I was just expressing a view that we seemed to have slightly lost some of the sense of "wreck orientation" that went along with manoeuvring via transits. The fact that the "true heading" number spat out by a GPS unit is often crappy at low hull speeds in a lumpy sea doesn't help either. A good compass can overcome this to some extent but just adds to the sense of being "ruled by numbers" with hardly time to look up and glance the shoreline horizons.

Other news from the boat show was that the long awaited Pope's Eye live video feed "Reef Cam" (& "Gannet Cam") is getting close to going live. The launch date was supposed to be last February! I was told that several months delay to Telstra's work on the project was due to the arrival of the nbn in Queenscliff.

There was also mention of some camera damage that needed fixing. The Parks guys seemed well please with the test video streams they can view. Fingers crossed that all goes well this project which was the brainchild of "The Nature Conservancy Australia". They have put in a bucket load of time & dollars into it.

cheers,
packo
Last Edit: 4 months 1 week ago by packo. Reason: colour adjust

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