Russel Island, Rocky Point Power Lines

[undercutter]

We wanted to pass through the main channel heading south from Brisbane to the Gold Coast and noticed the the Overhead Power Lines near rocky point is shown as 66' min clearance at HAT on the charts. It also looks like there is lots of width in the channel with 1 pylon in the water and the easterly one just onshore. Our air draught is 23.5m.

Has anyone with similar height navigated this channel successfully passing under the power lines. Looks like if we pass close to either side of the channel at a low tide we would have no problem but would hate to have to turn back and go all the way around Moreton Island and back down the coast.

Presently at manly harbour waiting for some warranty work on our genset Monday.

[Jim Cate]

A question many have asked! And the answer for us is that while there is greater vertical clearance nearer the towers, there is less water depth... and the charts are not all that helpful*. Our air draft is around 70 feet including the VHF, and we have safely passed under in the center of the channel and that is about where the lowest part of the wires is. Well, I guess i should say successfully rather than safely, for I don't know how close we were to disaster!

We have anecdotal evidence of taller masts making it ok, but can't vouch for the truth of the tales... and the sparks would be scary if one was wrong! You might ask around at RQYS... some of the mid size racers may have useful info for you, for their masts are likely around the same height as yours.

* The depths around there change more often than they are surveyed! Our last trip through there a few months ago we hit an uncharted shoal at 27d 42.202m S, 153d 21.645m E, less than 6 feet near local HW. That location is about 85 meters NW of the green beacon marking the edge of the channel (ie, inside the "channel") and just to the south of the overhead wires.

It is such a useful waterway... a shame that better info is not available.

Good luck,

Jim

[undercutter]

Thanks for the info Jim. We will definitely ask around at the RQYS for more info as I agree we don't want the sparks to fly.

Also appreciate the coordinates of the bank. Will keep away if we end up going that way. Be a real shame to have to go around.

On another note, how do you manage to deal with Oz immigration and visa requirements. I know you guys have been mucking around these parts for years. Did you become landed immigrants or do you have to keep applying for and extending your visa's. Maybe you just leave the country and then reapply for visa's. And how do you deal with customs as they will only give you 2 years on a temporary import of the boat and then you have to leave for at least a year, or did you pay the duty???

Just curious as we are in the process of renewing our visa's now and due to the medical requirements the total cost will be around $1280.00A for the both of us.

You could send me a PM as I would be interested to know if there is an easier way.

[Alan Mighty]

Originally Posted by undercutter

We wanted to pass through the main channel heading south from Brisbane to the Gold Coast and noticed the the Overhead Power Lines near rocky point is shown as 66' min clearance at HAT on the charts. It also looks like there is lots of width in the channel with 1 pylon in the water and the easterly one just onshore. Our air draught is 23.5m.

You've a copy of Beacon to Beacon?


If my air draught was 23.5m, I would look for a different route.

Does your draught rule out the Canaipa Passage?

See Rocky Point.jpg, about 52 KB.

[Jim Cate]

Originally Posted by undercutter

Thanks for the info Jim. We will definitely ask around at the RQYS for more info as I agree we don't want the sparks to fly.

Also appreciate the coordinates of the bank. Will keep away if we end up going that way. Be a real shame to have to go around.

On another note, how do you manage to deal with Oz immigration and visa requirements. I know you guys have been mucking around these parts for years. Did you become landed immigrants or do you have to keep applying for and extending your visa's. Maybe you just leave the country and then reapply for visa's. And how do you deal with customs as they will only give you 2 years on a temporary import of the boat and then you have to leave for at least a year, or did you pay the duty???

Just curious as we are in the process of renewing our visa's now and due to the medical requirements the total cost will be around $1280.00A for the both of us.

You could send me a PM as I would be interested to know if there is an easier way.

One thing Ifailed to say about that shoal: the coordinates are only where we got stuck... I don't know how big it is, and for that matter, if it is still there! We had sailed over that same area many times before without issue, and i suppose that such things can go away just as they can appear... without warning!

Re visas: years ago we applied for and were granted class 410 visas, then called "retiree visas". It was a PITA to get, but once issued, it classes us as temporary residents, and was initially granted for 4 years. We have had two additional 4 year renewals, and the last time it came for 10 years. Don't know why! But sadly, this visa is no longer offered.

Re customs: We imported our previous boat, thinking correctly that we were likely to sell her in Oz at some time, so that satisfied the customs folks for her. This boat was built here in Oz, and so is no issue. Life is good on the bureaucratic scene for now!

Jim

[undercutter]

Originally Posted by Alan Mighty

You've a copy of Beacon to Beacon?


If my air draught was 23.5m, I would look for a different route.

Does your draught rule out the Canaipa Passage?

See Rocky Point.jpg, about 52 KB.

Draught is 7 feet so it looks a little tight for the banks!! Not sure what the tides are there as the closest stations are Runaway Bay and Brisbane Bar. Would think they would be a little higher in the passage but am not 100% sure. Even so, my charts show the power lines over the Canaipa Passage at 65.5 feet so less than the Main Channel?

Does the Beacon to beacon show something different?

[Alan Mighty]

Originally Posted by undercutter

Even so, my charts show the power lines over the Canaipa Passage at 65.5 feet so less than the Main Channel?

Does the Beacon to beacon show something different?

Ouch! You're right. Beacon to Beacon shows the air draught clearance in the northern approach to the Canaipa Passage at only 20.0 metres at HAT.


All of that suggests to me that you reconsider rounding Cape Moreton.


You can download Beacon to Beacon from the Maritime Safety Queensland website.


For Moreton Bay, point your browser to: Moreton Bay guides (Maritime Safety Queensland)

[Jim Cate]

Originally Posted by Alan Mighty

You've a copy of Beacon to Beacon?


If my air draught was 23.5m, I would look for a different route.

Does your draught rule out the Canaipa Passage?

See Rocky Point.jpg, about 52 KB.

It would be so much better if beacon to beacon showed depths on their charts. As it is, they are not very useful to me, or most anyone with a keel boat.

The path with the most hope of success would be quite near the eastern tower, where the wire is visibly a lot higher than over the channel center. Some sounding from a dinghy would be required to plot it out, and once under the wire, a quick return to center channel to avoid the shoal. Might work... but as undercutter said, it's a long way back if it doesn't work out!

Jim

[Alan Mighty]

MSQ does admit to including an unspecified 'safety margin' in their calculations of vertical clearance.

Jim Cate's idea to sound near the eastern bank sounds good.


You would also need a means of assessing the vertical clearance.


See safety margins for overhead cables.jpg

[Alan Mighty]

Originally Posted by undercutter

Not sure what the tides are there as the closest stations are Runaway Bay and Brisbane Bar. Would think they would be a little higher in the passage but am not 100% sure.

The Queensland Tide Tables publish tide corrections for Rocky Point. See Tides at Secondary ports.jpg or point your browser to: Queensland Tide Tables (Maritime Safety Queensland)

[Alan Mighty]

CSIRO publishes an animated GIF showing the astronomical tide forcing in northern Moreton Bay. The GIF lags reality by about one week, so it's not useful for prediction. It is useful for seeing where and what the tidal currents are and what they do.

I don't know of anything similar for southern Moreton Bay.


To see CSIRO's animated GIF, point your browser (and wait) to: http://www.marine.csiro.au/~and371/s...m_mb2_plan.gif

[Alan Mighty]

Originally Posted by Jim Cate

It would be so much better if beacon to beacon showed depths on their charts. As it is, they are not very useful to me, or most anyone with a keel boat.

Of course reliable depths would be better, Jim.


The reality is that Moreton Bay, like Great Sandy Strait, is a dynamic waterway with much change. So reliable channels and their depths change.


MSQ handles that by moving buoys. And you know well the dynamic game that is the Wide Bay Bar.


Remember that until 1856, the recommended entrance to Moreton Bay was via South Passage Bar. The dynamic or shifting sand changed that, after a much publicised grounding of a German-flagged vessel. That incident sparked the construction of the light on Cape Moreton and recommendation to enter Moreton Bay from N, not E.


The current on-line version of Beacon to Beacon notes that depths have not been resurveyed since floods in 2011 and 2013 poured more sediment (and other debris) from rivers into Moreton Bay.

[JPA Cate]

undercutter,

Really, check the numbers. It looks to me as if the wires lack a wee bit over 2.5 m. to clear your masthead, and that seems likely to exceed the "safety margin." Finding out the safety margin still may leave you with a question. Hitting the wires would have dire consequences. If it were me, in your situation, would you tell me something like, "Just bless your boat for having a nice tall rig for light air sailing, and go on around?"

We have often left via the NE channel, and one year the tide was right to use the Kianga Channel, which takes out quite a bit of distance... We draw 2.2 m., so you really need some high tide help if you do that. We would probably go around, though, with new bottom paint--it's a pretty skinny route for us, and as Alan says, "dynamic", or "shifty & treacherous" as I might say.

Cheers, Mate,

Ann

[undercutter]

Originally Posted by Alan Mighty

The Queensland Tide Tables publish tide corrections for Rocky Point. See Tides at Secondary ports.jpg or point your browser to: Queensland Tide Tables (Maritime Safety Queensland)

Just saw Ann's post as I was writing this as I was thinking it was looking pretty good. Now I might have to rethink as we just had the bottom done as well.

It looked like according to your table that we could have gained about 2m on a LWS right in the middle of the channel. Hugging the east bank would have to gain us a considerable amount as well considering the amount of sag in the wire(s), at least 2m more. So that would be 4m altogether.

It is interesting in that it looks like they have recently changed the clearance height in the charts as the coral coast guide I have says the clearance is 2m more and the 1988 edition of Moreton bay and how to Fathom It shows 27.3 m and the power lines at Canaipa passage at 28m. I wonder if the minimum clearance standards have changed (maybe higher voltage now) or maybe the sea levels are rising!!!!!

[Alan Mighty]

Originally Posted by undercutter

It is interesting in that it looks like they have recently changed the clearance height in the charts as the coral coast guide I have says the clearance is 2m more and the 1988 edition of Moreton bay and how to Fathom It shows 27.3 m and the power lines at Canaipa passage at 28m. I wonder if the minimum clearance standards have changed (maybe higher voltage now) or maybe the sea levels are rising!!!!!

I could well imagine that the power lines have been changed since 1988. Russell Island and North Stradbroke Island have much higher populations, with much higher electricity demands, since '88. I would guess that electricity demand to North Stradbroke increased with activity in the sand mining operation and higher tourist visits.


So I would rule out trusting in the 1988 'Moreton Bay and How to Fathom it' (a wonderful book. I grew up loving it.I have a treasured 2nd edition and regret that I gave away a copy of the '88 edition).


Alan Lucas, author of 'Cruising the Coral Coast', has a good reputation for attention to detail. But I cannot vouch for when he last checked those cable clearance figures.


You could try contacting MSQ. I've visited the Pinkenba office (see details at: Contact a regional office (Maritime Safety Queensland)) to buy charts and always found them approachable, particularly when I've had a question that relates to their charts. My guess is that if you made a personal visit to Pinkenba MSQ, you might be lucky enough to speak to the right person. A phone call might work too.


Looking at the time, if you want to make miles S this weekend, the notion of visiting MSQ is academic.


The weekend forecast is for light winds E and SE. Daytime low tides if you want to try your luck at Rocky Point in the Main Channel. Or spend the weekend working back N in Moreton Bay, ready to round Cape Moreton. I note a forecast for 15 knot SE on Monday and Tues, dropping to not much on Wed and Thurs.


I'd not trust a local cruiser unless they definitely have an air draught greater than your own. Locals who work southern Moreton Bay frequently usually have boats with water draught and air draught that slip through without problem.


I'd be looking for a boat with an air draught of at least 24 metres to follow. And hoping for a cold day (on hot days, those cables likely sag a little more than cold ones).


Other than that, you're understandably stuck in a mire of doubt and uncertainty, the Dirty Harry situation of 'just how lucky do you feel'.


If you've not found satisfaction with a rigger at Manly, I suggest you try contacting Colin Quin and work out something such as a berth in Scarborough Marina (Quin often drives down to Scarb Marina to do rigging work). Failing that, Fletch at the chandlery (Boat Harbour Marine at Scarb Marina: see Boat Harbour Marine) does rigging and may be amenable to doing a rig inspection for you to satisfy your insurer. From Scarb Marina, you could head to sea via Cape Moreton.


Note also the anchorage on Moreton Island called The Sandhills or Slaughters Gutter. A very pleasant anchorage - it has very little tide affect so boats generally sit to the wind, a clean sand bottom, and presents an easy opportunity to dinghy ashore to Moreton Island and to walk across the island to the Pacific side, via the sandblows or sandhills. I'd suggest anchoring at The Sandhills rather than the Wrecks off Tangalooma.