Rep (1991) PA

Post by **Silkie** » Sun Jun 08, 2008 7:37 pm

Thinking particularly of the "obstruction" east of Heather Island - in Oban Bay for goodness sake. Surely if there was something there it would be more definite than reported in an approximate position by now? And if not why is it still on current charts? Is this the sort of thing that springs into being to save some poor master's career when he has in fact hit Heather Island itself?

Does anyone else pay any attention to these vigias?

Arghiro · Post by **Arghiro** » Sun Jun 08, 2008 8:45 pm

FWIW I try to avoid any dodgy bits by a mile. However, as PA is a fair description of my own location at any given moment I could well be in more danger than I thought.

My understanding of charts (OK I am no expert) is that most of them were surveyed hundreds of years ago - and done properly! More recent updates are likely to be electronic "reassesments". Now my Garmin 76 GPS has track errors of around 100' when I drive along local roads. And I KNOW the roads ain't being moved. No self-respecting surveyor would accept a 100' error in a map or chart produced by manual methods.

Now back to "PA" rocks. The person who first reported them has not been in a position to carry out triangulation (and who can blame them, they will have had survival on their minds) and no-one has ever found them since so PA they remain. they could be miles from where reported. It makes complete sense to me that they remain PA. How much detail physical surveying is done today? Slightly less than b@gger all I expect.

Post by **Silkie** » Sun Jun 08, 2008 9:38 pm

Agree with all you say (although I'm not sure about the 100' error on your gps) but this is Oban Bay and there will have been tens, if not hundreds, of thousands of vessels in this approximate position over the last 17 years. The area is hoaching with diving schools too and you'd think someone would have been curious enough to investigate.

Daveanmucker · Post by **Daveanmucker** » Mon Jun 09, 2008 5:24 pm

Excuse me if I'm being a bit thick but am having trouble understanding this thread and as I sail by Heather Island both to the East and the west I am interested to understand.

Firsty what is "Rep(1991) PA" that you refer too and what does the word vigias mean can't find it int dictionary.

Post by **Silkie** » Mon Jun 09, 2008 10:56 pm

Admiralty charts show an obstruction about 30-50m east of Heather Island towards the northern end (from memory as the charts are aboard) which was REPorted in 1991. It's Position is described as Approximate. I presume that someone said they hit something there.

Vigia n.
A warning on a navigational chart indicating a possible rock, shoal, or other hazard, the exact position of which is unknown.

The Free Dictionary

There's another one out in the middle of the Firth of Lorne IIRC. I just wondered if others took them seriously or not.