Is it just me or is the RNC vastly more obvious than the ENC?
Sand Pebble - my old-ish plotter will do a route check if I set that function on, so this tech has been around for some time.
But that’s the double edge sword in this situation, for this type of vessel’s use case running into backwater bays and rivers that haven’t been Surveyed since Lincoln was the president, you’re going to have a lot of unknow obstructions of unknown depth that may or may not be there. That’s a lot of magenta crosses that may or may not be awash rocks. I agree the RNCs are the better option in this case, but sadly, they have about 5 months left.
It seems since the early 2000’s newer vessels that I worked on had/has machinery space automation systems with some points that can’t be disabled or ignored. Low lube oil pressure, high coolant temp, high fuel level on tanks vented to deck, etc. can’t be disabled without a password. We can disable/ignore an alarm for a ballast valve, high water tank level or a watertight door being left opened but not a flooding bilge. Critical alarms can be silenced for a short period of time but they keep resounding until out of alarm state. If the consensus is AI isn’t needed in ship navigation systems like we have in automobiles at least update the tools to attempt to make them dummy proof. Can everything be ignored or silenced on these navigation system? Thank goodness no oil was spilled.
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Is that correct? I don’t know. Shouldn’t be much concern in Bristol Bay, Bering Sea or Shelikof Strait as long as the vessel stays far enough offshore. False Pass might require local knowledge.
The charts of Kupreanof Strait might have issues but there’s a known and documented (relatively) safe route through there. We used to use Kupreanof Strait and Marmot Bay on a Coast Guard Cutter.
Good point about the RNCs going away. I prefer ENCs charts myself. My point was it’s much easier to use the Coast Pilot while keeping a second screen open with a chart. ENC would be better imo because of the ability to change scales easily.
Edit: Here’s the section on Shakmanof Cove:
This is what it looks like zoomed in on the NOAA ENC Viewer
Most tug and barge companies do not provide any training. They just assume that experienced and licensed guys know what they need to. There maybe some poor quality videos onboard or CBT (OSHA type) “safety” training that the USCG accepts to meet requirements.
Rosepoint has some pretty good CBT on how to use the program. However, I don’t recall any great detail.
I prefer the old and familiar raster charts. I think they will remain available online and in wheelhouse draws for a long time, even though they are not updated.
I suspect that there will be a few ENC aided groundings.
I often run the ENCs of my laptop alongside the Rasters on the boat’s plotter.
The ENCs apparently have been updated with satellite data. Alaska rivers and parts of the coast that have either never been surveyed or have not been surveyed since the 1800s are much more accurately portrayed on the ENCs, but you’ll still find a few places where you are traveling over charted land or the river is much different than charted (of course, there are usually no soundings).
Rivers change with ice out and high water spring currents eating a way the river bank and some sand bars, as river levels drop and the current slows sand bars build.
Recent, surveying in Alaska is only shown on the ENCs. This can be somewhat helpful, parts of Etolin Strait are a good example (new surveying after a Norwegian tanker touched bottom a few years ago).
Some boats have satellite photo “charts” for use in shallow parts of Alaska. These should be mandatory.
A lot of Alaska will never be charted or resurveyed. It’s over 28,000 miles of coast line, thousands of miles of uncharted rivers, and many changeable areas. The human population is tiny, there is very little recreational boating, many areas have little or no commercial fishing, and very little seasonal commercial shipping. The northern most USCG seasonally buoyed channel is the lower half of the Kuskokwim River. North of that, there are only a few fixed seasonal aids (most of which have no practical value) that are serviced by helicopter. Drake Construction seasonally bouys the channel into Kotzebue. The USCG is barely present in Northwestern Alaska. The icebreakers Polar Star and Healy are seen occasionally anchored off Nome or steaming well off the shallow coast.
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The charts of the Yukon River bear only a vague resemblance to reality. Huge river, mind you. The river changes every year but marine traffic is so light as to not warrant the expense of annual surveying. The first boat of the year after ice-out goes up on last year’s waypoints , finds a new way around the mud bars and passes the waypoints to the next captain — if they are friendly.
By the way, the best tide predictions for crossing the bar came from the Admiralty tide predictions, not the US. Don’t know why.Important up there because the bar is only 8 feet if I recall. Surprising for such a huge river. Much deeper on either side of the bar.
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I know someone who worked on the charts for Alaska at NOAA. No one took a detailed survey of every singe rock near the beach, a lot of what you see near shore is from 19th and early 20th century WRITTEN descriptions and sketches of what the person was looking at. He was doing his best to fill in random rocks and such in a way that made sense and kept people out of dangerous areas.
To be fair, outside of a canoe or kayak no one is going to try getting a boat around 101 rocks right off the beach unless they are nuts.
Farther out YMMV. The NOAA survey boat for my area ties up next to me in the winter, they have a pretty sophisticated side-scan sonar and can capture obstacles and such on either side of the boat and fill in the blanks from the old surveys that were more or less what was directly under the boat. If you are in an area not recently surveyed with this modern gear and off the usual channels, you could very well find a surprise. Speaking of surprises, that ENC chart still is poor IMHO. The little cross covers up the 4-foot shoal that is really obvious on the RNC.
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Oil and coolant temp are the only ones I have that I can’t turn off without wire cutters, but being uninspected no one cares what I do.
There is another long thread on here about the various shortcomings of alarm systems compared to modern best practices found on many aircraft. If you are looking for a marine version of Ground Proximity or TAWS, they both exist more or less but both would be going off all the time in certain circumstances.
Unless you set the depth finder warning to 6 inches, there are times when you are barley making it up some shallow channel it would never stop squawking. A marine TAWS equivalent would be great out in the ocean, but going up a twisty channel or river you would never NOT be aimed at shallow water or land unless you set it to only look like 50 yards ahead. Then you add in various uncharted or poorly charted areas and the poor thing might just green light you right into a rock.
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NOAA is working to update much of the antiquated or insufficient charting of Alaskan waters. However as you note this is a HUGE task and will likely take decades; especially when you consider the developing needs in the vast and very poorly charted areas of the Arctic.
The location of the incident of this thread however is in an area that was surveyed in 2011 with complete bottom coverage. Charts of this area have been updated with any new or significant changes, especially as it relates to Dangers to Navigation.
As mariners using charting products, especially in a patchwork charted area like Alaska, it is critical to have an understanding of Category Zone of Confidence (CATZOC), which is the ENC equivalent manner of communicating what used to be summarized in the Raster Chart Source Diagram.
Charts are only as good as the data used to make them and mariners need to be aware that even on short voyages they can easily transit between areas that have recent complete bottom coverage surveys made using modern sonars and areas with soundings made using lead line on the very same chart.
When navigating, especially in Alaska, mariners should frequently be bringing up the CATZOC layer overlay to better understand the confidence of the charting in the area they are in and in the areas they will be going to. How much faith or trust to put in a chart and its associated data and how to navigate in relation to potential known or unknown hazards needs to be an informed decision.
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Soundings in fathoms, it’s 24 feet. It’s shown as a 7.3 meter shoal on the ENC viewer.
“…no one is going to try getting a boat around 101 rocks right off the beach unless they are nuts…”
Unfortunately, there’s a lot of them about. See, for example…
…especially the chart images.
“oh, there’s nothing on the chart, so it must be OK” or something like that!
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My thought is if there is no way to safely get a survey boat in there, all the chart info comes from some guy with a sketchbook standing on a rock 100 years ago.
That makes it a bit more obvious, I would be going wide of all that myself, or at least I hope I would.
Badly drawn rocky island off a badly drwan rocky headland - duh!
Quality of the survey was not a factor here.
Here’s the source Diagram NOAA Chart 16594. Marmot Bay and Kupreanof Strait. Shakmanof Cove marked in red:
Shows Shakmanof Cove as “A 1990-2015 NOS Surveys full bottom coverage”
Rock_Hill posted above the survey was done in 2011.
One issues with using a RNC here is the scale; it’s 1:78,900, too small to be very useful in Shakmanof cove.
Good data for that area exists so zooming in a ENC is going to result in a better chart with good quality added detail. - Except the topography of the shore is missing, that’d be good to have.
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This is in no way meant to exonerate sloppy pilotage in challenging waters, however, even with detailed bathymetric information, that rock somewhat comes as a surprise…
[Depths are in Meters]
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That report is kind of comical. They had safety plans, safety checklists, procedures, and so on up to their eyeballs and then took off at about 15 knots in the dark in a barely-charted area full of rocks anyway.
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Never seen that. Is it Navionics?
I would be very wary of how the contours presented in the above figure are created and what they represent. I would definitely not call those contours “detailed bathymetric information”, unless perhaps woefully out of date. It looks more like interpolation based on older sounding data, which would likely be lead line data given that was what was available prior to the 2011 survey. Those contours are NOT NOAA contours and are NOT representative of the most recent NOAA survey data.
Here is a very course snapshot of the area from the NOAA 2011 data:
For those interested all the data and info associated with the 2011 survey can be found here:
https://www.ngdc.noaa.gov/nos/H12001-H14000/H12317.html
It’s kind of amazing that NOAA / Dept. of Commerce provides all the electronic charts and their corresponding source data free and available to anyone in the world. I don’t know of any other nation that does this.
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Yes, Navionics >>>
https://webapp.navionics.com/?lang=en#boating@12&key=c}o`Jdnlb\
If the contour lines do not show up, then button on lower left >>> Sonar Chart.
However, I have no idea where their data is coming from.
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