Would You? - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest Forums > Seamanship & Navigation
 Not a Member? 

Seamanship & Navigation Forum devoted to seamanship and navigation topics, including paper and electronic charting tools.


Like Tree8Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 10-03-2011
davidpm's Avatar
Senior Member
 
Join Date: Oct 2007
Location: Madison
Posts: 3,485
Thanks: 130
Thanked 33 Times in 26 Posts
Rep Power: 7
davidpm is on a distinguished road
Would You?

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?
Attached Thumbnails
Would You?-glencove.jpg  

Last edited by davidpm; 10-03-2011 at 11:45 PM.
Reply With Quote Share with Facebook
  #2  
Old 10-03-2011
Classic30's Avatar
Once known as Hartley18
 
Join Date: Aug 2007
Location: Melbourne, Australia
Posts: 4,258
Thanks: 18
Thanked 24 Times in 24 Posts
Rep Power: 8
Classic30 will become famous soon enough Classic30 will become famous soon enough
Quote:
Originally Posted by davidpm View Post
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.
__________________
-
"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"

Last edited by Classic30; 10-03-2011 at 11:45 PM.
Reply With Quote Share with Facebook
  #3  
Old 10-03-2011
PBzeer's Avatar
Wandering Aimlessly
 
Join Date: Nov 2002
Location: Cruising
Posts: 19,069
Thanks: 0
Thanked 61 Times in 60 Posts
Rep Power: 14
PBzeer has a spectacular aura about PBzeer has a spectacular aura about PBzeer has a spectacular aura about
I'd agree with Hartley.
__________________
John
Ontario 32 - Aria

Free, is the heart, that lives not, in fear.
Full, is the spirit, that thinks not, of falling.
True, is the soul, that hesitates not, to give.
Alive, is the one, that believes, in love.
JCP


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- Website & Blog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #4  
Old 10-04-2011
celenoglu's Avatar
Senior Member
 
Join Date: Dec 2008
Posts: 529
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
celenoglu is on a distinguished road
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.
Reply With Quote Share with Facebook
  #5  
Old 10-04-2011
Yorksailor's Avatar
Senior Member
 
Join Date: Oct 2009
Location: Pacific side of Panama
Posts: 416
Thanks: 8
Thanked 10 Times in 9 Posts
Rep Power: 5
Yorksailor is on a distinguished road
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.

Phil
Reply With Quote Share with Facebook
  #6  
Old 10-04-2011
Senior Member
 
Join Date: Feb 2010
Location: Narragansett Bay
Posts: 8,258
Thanks: 6
Thanked 88 Times in 85 Posts
Rep Power: 6
Minnewaska will become famous soon enough Minnewaska will become famous soon enough
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.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Jeanneau 54DS

In the harsh marine environment, something is always in need of repair. Margaritas fix everything.
Reply With Quote Share with Facebook
  #7  
Old 10-04-2011
pdqaltair's Avatar
Senior Member
 
Join Date: Nov 2008
Location: Deale, MD
Posts: 1,942
Thanks: 1
Thanked 12 Times in 12 Posts
Rep Power: 6
pdqaltair is on a distinguished road
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.
__________________
(when asked how he reached the starting holds on a difficult rock climbing problem that clearly favored taller climbers - he was perhaps 5'5")

"Well, I just climb up to them."

by Joe Brown, English rock climber




To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #8  
Old 10-04-2011
Yorksailor's Avatar
Senior Member
 
Join Date: Oct 2009
Location: Pacific side of Panama
Posts: 416
Thanks: 8
Thanked 10 Times in 9 Posts
Rep Power: 5
Yorksailor is on a distinguished road
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.

Phil
Reply With Quote Share with Facebook
  #9  
Old 10-04-2011
St Anna's Avatar
Senior Member
 
Join Date: Mar 2003
Location: Southern QLD, Bayside
Posts: 1,428
Thanks: 1
Thanked 1 Time in 1 Post
Rep Power: 12
St Anna is on a distinguished road
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.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by St Anna; 10-04-2011 at 07:28 AM.
Reply With Quote Share with Facebook
  #10  
Old 10-04-2011
Ilenart's Avatar
Senior Member
 
Join Date: Jul 2007
Location: West Australia
Posts: 497
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 7
Ilenart is on a distinguished road
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.

Ilenart
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



All times are GMT -4. The time now is 09:08 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012