"not to be used for navigation purposes"

[Jaguar 25]

Just looking at the tidal stream info on visitmyharbour.com and the usual "NOT TO BE USED FOR NAVIGATION PURPOSES" warning comes up.

1. Is there any problem in using this tidal stream info for navigation? It is identical to that shown in the Reeds almanac.

2. Is there any problem in using visitmyharbour charts for navigation?

Regards,

 

[marklucas]

They're just covering their ar$e$.

 

[Angele]

My chartplotter comes up with a whole screen full of disclaimers when turned on, courtesy of either Raymarine or Navionics (not sure who to point the finger at). I probably read it once when I got the boat. Now I don't bother - I just press the "ok" button immediately.

Pretty certain, though, that "not to be used for navigation" would appear in there somewhere...

 

[dylanwinter]

They're just covering their ar$e$.

indeed they are

you are also not supposed to be able to download their charts

however, apparently there are ways of getting round things

or you can use a screen grabber to grab pages for futuire reference


D

 

[[70521]]

It is only an aid to navigation, a bit like my echo sounder.

 

[dylanwinter]

It is only an aid to navigation, a bit like my echo sounder.

I did get an email suggesting that I should put a disclaimer on the ends of my films saying that they were not to be used for navigational purposes

I also once had a flymo that came with a warning that it was not to be used for cutting hedges

 

[mjcoon]

I also once had a flymo that came with a warning that it was not to be used for cutting hedges

My hot air paint stripper instructions warned against using it as a hair dryer...

Mike.

 

[AntarcticPilot]

For 30 years, I was involved in map-making. We made maps of Antarctica primarily, and we were the best source of map data for Antarctica, bar none. However, we always noted that our maps were "not for navigation". Yes, it was covering our backs - but for a very good reason. The potential damage claims if we hadn't said that would have been astronomical, quite literally. Suppose that a cruise ship had used our data to navigate and had hit a rock we hadn't marked? Hundreds of lives lost, massive pollution, vast salvage and clean-up operation. You can imagine the costs that would be incurred - and we were a goverment organization, and government organizations don't carry insurance except where legally required to; otherwise we were supposed to self-insure. But I doubt you could get insurance adequate for a situation like that, anyway. Antarctic mapping, as you might guess, is subject to significant errors and data gaps, but there are reasons why it it sensible even if you're sure the original data are good.

Hydrographic Offices usually have legislative protection, so they don't need to put disclaimers on their products; they also have protocols in place to ensure that their products are multiply checked and are as good as they can be (I've been part of the process for Antarctic charts). Other organizations don't , so they do have to state that their products aren't suitable for navigation so that people are aware that they are using them at their own risk. It isn't a disclaimer, by the way, it is a statement of intended use.

Redistributors of electronic products have to do the same thing because they can't be CERTAIN that the data will be used in ways that are compatible with the data. Zooming, automatic generalization and other useful electronic trickery mean that the provider of the data can't know what the end-user is actually seeing. They don't even know that the equipment it is being used on is suitable - perhaps it is being viewd on a monochrome screen, or the device has a few dead pixels? Or the person has the colour balance set up totally wrong, so colours aren't distinguishable, or have utterly wrong values? So, "Not for Navigation" - meaning that you should use this for information and situational awareness only - is the best way forward.

 

[prv]

Visit My Harbour's £25 chart package is intended for navigation. It's just the free chartlets on the site which aren't. The difference is apparently the kind of license they buy from UKHO - if you promise to write "not for navigation" on it then it's cheaper.

Pete

 

[vjmehra]

I subscribe to the £25 package and everything says not for navigation on it...

 

[prv]

I subscribe to the £25 package and everything says not for navigation on it...

That's interesting. They definitely have some product which is "for navigation" - their blurb is quite proud of that fact. Apologies - must be something else.

EDIT: yep, it's a different service. I got the two mixed up: http://www.visitmyharbour.com/charts-for-seaclear.asp

Pete

 

[ffiill]

Even the old Admiralty RYA plotter CDs used to say something like this.
If you want an alternative free tidal data prediction programme go to
www.mdr.co.nz
Whilst some of the Admiralty stations dont appear the data is Liverpool University Proudman institute derived and totally accurate in my experience.
Its also available as a free App on Google Play-search for Tide Prediction

 

[vjmehra]

PRV I wasn't aware of that service, but it looks very interesting....

 

[oldbilbo]

If you want an alternative free tidal data prediction programme go to
www.mdr.co.nz
.....the data is Liverpool University Proudman institute derived and totally accurate in my experience. Its also available as a free App on Google Play-search for Tide Prediction

Er, it's not actually free, but is offered 'free to try' with a registration nag after a while, if you continue to use the prog.

I offered a comment to the author-guru Phil Thornton re his stuff being stuffed into the SpamBox by Firefox - which any bright and alert forumite would suss - and he responded positively and swiftly. Augers well....

 

[macd]

The potential damage claims...would have been astronomical, quite literally.

Does that mean the lawyers would have been ejected into deep space? Sounds like a good idea to me.

 

[AntarcticPilot]

Does that mean the lawyers would have been ejected into deep space? Sounds like a good idea to me.

Yes, that does sound like a good idea! Sadly, I meant that the amounts involved would be in the sort of numbers that would make a roll-over jackpot win on the Lottery look like small change.

 

[dedwards]

Their terms and conditions do spell things out: The nav charts are not for nav because they don't have lat/long numbers on them, are not necessarily up to date and their dimensions can become distorted.
As for tidal stream maps: they are for calculating tidal streams and are pretty useless as navigation charts.

 

[bigwow]

Bought a one man brake bleeding kit from Snap-On in the 80's we were most amused by the slip of paper inside the packaging saying "not to be used on the human body"

 

[macd]

Bought a one man brake bleeding kit from Snap-On in the 80's we were most amused by the slip of paper inside the packaging saying "not to be used on the human body"

Aprilia RS250 handbook: No part of this motorcycle is edible. Make your own arrangements for lunch.

OK, I made the last bit up.

 

[Vara]

I also once had a flymo that came with a warning that it was not to be used for cutting hedges

Really, ideal tool for calming hedges and pruning lavender.