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davidpm 10-03-2011 11:36 PM

Would You?
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We are just east of Glen Cove NY, traveling West at about 6+ knots at night.

I had just taken the helm and was following the course the captain had set.
I'm primarily watching for traffic of course there is not much else to do as the autopilot was on.
I'm thinking I should check the GPS just to make sure. Just then I see G"21" and I'm thinking that sometimes they put the buoy's up because something bad is nearby.

I checked the GPS and immediately make a course correction to pass the buoy on my port. The captain said that he wasn't worried because those rock symbles were about rocks really deep. We draw 6 feet.
I was not so sure.
On the chart below, the red course line goes right through the symbol Rk. The way I read it when it says Rk with no depth it means it could be a problem.
I my defense my GPS shows even less information and only shows the danger area just above the line with no depth and the RK with no other info and the blue area below the line with no depth so I thought I had to dodge three things not just one. I notice that the GPS even on highest resolution leaves out some information that is on the chart
But maybe I'm just being too cautious.
What do you think?

Classic30 10-03-2011 11:42 PM


Originally Posted by davidpm (Post 782405)
But maybe I'm just being too cautious.
What do you think?

I think you can never be too cautious - especially at night.

With a rough sea or an especially low tide you could hit something easily enough, and rocks and boulders are not something you ever want to hit in a keelboat. From the excerpt you've shown it would seem that the light on G'21' is there for a reason - to tell people not to cut the corner. ;)

PBzeer 10-03-2011 11:52 PM

I'd agree with Hartley.

celenoglu 10-04-2011 03:55 AM

Although electronic charts can have a lot details in a small memory compared to raster charts, unfortunately the vector charts are less informant than raster charts. Therefore it is never a good idea to rely on the maps of digital instruments.

Up to date raster charts or paper charts are the ones to be used.

Yorksailor 10-04-2011 04:43 AM

That is a big ship marker marking Matinecook Pt and going outside it is good seamanship. A court of inquiry would define going inside negligence if a serious accident occurred.

Cutting corners at night without local knowledge sinks boats!

It is also bad seamanship to assume that charts and chart plotters are 100% accurate. The mark 1 eyeball is much more reliable.

The rocky bottom was deep but if those soundings are in feet and you had crossed that 10ft mark in any kind of waves you might have bounced the keel through the hull.


Minnewaska 10-04-2011 05:29 AM

Going outside the ATN would have been cautious, not cutting the corner through a rocky point. Looks like it would have been a one min diversion. The RK and Rky notations indicate bottom composition. I've certainly seen my fair share of uncharted obstructions that could take out a 6 ft keel. They are most often in more desolate sailing grounds or places one would think a skipper would avoid anyway, like this one.

pdqaltair 10-04-2011 06:11 AM

Most GPS units have astatement when they are turned on that says...
... not to rely on one source of information. Depending on the unit, many are short on detail, and often locations are wrong.

Off course, I've seen mistakes on paper charts too. An old edition of a popular chart book for the Chesapeake had an entire sheet misnumberd by 1 minute!

Floating markers get moved off station by storms, often by hundreds of yards.

Just a few things to think about. I think everyone would agree that going inside that mark at night was silly, all things considered.

Yorksailor 10-04-2011 06:37 AM

If you sail full time like we do you see 2-3 boats a year on the rocks because of cutting corners at night. Last one was 4 weeks ago in Bonaire. The boat had crossed the Atlantic safely but she sank while being towed off after spending the night on the reef.


St Anna 10-04-2011 07:23 AM

is may cause some argument, but;

If you are sure it is well charted. The course is fine. If unsure - give a wide berth.

I sailed in places where the paper chart says "first charted by Capt ? in HMAS Rattlesnake, 1878 and aerial recon 1944." I then take into consideration wg84 (gps) is a bit different and reefs grow. => give it a wide berth. eg the crocodile islands above arnhem land NT. AUST. They are at least 2nm off the real position. I saw a reef which was not on the chart and therefore not on the plotter at least 15nm away from the nearest plotted reef. Ships dont go there so it is not re-surveyed. Another eg is the Louisiades.

Sailing in the USA where the GPS satellites were invented for (!) should be OK.

You are sailing in a yacht and must minimize, but make your decision and accept the risks involved. That is the way it is.

Ilenart 10-04-2011 07:52 AM

I don't think there is an issue with the course going thru "Rk" when your yacht draws 6ft. We have some similar rocks near my marina which are about 5m (16ft) down when the surrounding water is 7-10m deep. These rocks are actually marked as a "reef".

However in the circumstances you described I would of done exactly the same. At night in an unfamiliar area I would of altered course as well. If it was daylight and I was familiar with the area I may of cut the corner.


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