Originally Posted by colemj
And last, but not least:
I think we all
agree that the root cause in all the quotes you posted is the navigator, not the tools he/she uses. However it is possible that the tools are contributing factors.
In the past (pre GPS), the standard suite of navigational tools available to the navigator often returned inaccurate positional results. Part of the solution was not to rely on any one form of position fixing but rather to check one against the other and use as many as possible. Another part of the solution was to give charted obstacles a large clearance zone consistent with the perceived accuracy of your positional method.. And another was to reference what the eye could see of the real environment
to the charted information and not the other way around.
These were three basic navigational tenets, part of the navigator's philosophy, it is what we learned (either formally or otherwise); in order to become proficient at this trade
, one had to know
we now have a tool that is way more powerful in determining one position. GPS
gives consistent positioning data under almost every condition almost all the time. It is many orders of magnitude better than all other (non-electronic) form of maritime position fixing. I think we all know this and never doubt that the GPS position is the best - period.
So with this great tool, how / why to grounding continue to occur - that is what Rustic Charm (as OP) and other's like Jim, question.
Originally Posted by Jim Cate
I simply can't understand why they cut it close... no matter what form of navigation they were using.
Let's look at two aspects, one being the an experienced navigator
and the other the in-experienced (or untrained) operator
In the OP's example (and many others), clearly at least one of the three tenets
above were violated but why?????
What logical explanation is there for failing to observe some or all of these "rules". I along with others speculate that the GPS & Chartplotter
lured or seduced the navigator into making these mistakes
The mechanics of this have already been well explained but to recap.
1. The consistently fantastic accuracy of GPS can lead (lure?) one to forego using far less accurate means to cross check.
2. The GPS position seamlessly overlaid
on the chartplotter
can lead one into forgetting the accuracy of the charted information is way way less than that of the position fix thus resulting in reduced clearance zones (or perhaps not even using clearance zones.)
3. Having a chartplotter visible in front of you all the time can lead one to take this as the reference data and apply it to the outside world rather than the reverse.
They do not suggest the GPS / chartplotter are the root causes but they are logical explanations of how/why all three tenets were violated and thus they can be considered contributing factors.
I realise there will be other logical explanations and I would be interested in hearing yours. However other logical explanations need not invalidate the explanations above.
In the case of the in-experienced (or untrained operator)
, one logical explanation is far more simple.
Newbie buys a boat and wants to go somewhere new, the local shop sells him latest chartplotter/GPS already loaded with charts. Within minutes of powering it up, he has a nice picture of his local harbour with the position of his boat clearly shown. He moves his boat out into the open waterway and and he sees the position of his boat moving ever so nicely of the display or perhaps the display is moving nicely around his boat. He looks around and sees it matches his surrounding. He reads a bit of the manual and works out the zoom and sees just how accurate the GPS derived position is. It is all very intuitive and he sees this a great way to get about and into the great unknown adventures that await him up or down the coast. What could go wrong?
Well, not has he already violated the three tenets of navigation, he doesn't even know they exist.
He has never had the opportunity to learn them or be made aware of them. He didn't need to ask others or take lessons (formal or otherwise) in navigational techniques, the new box seemed to do it all for him. The real question should be "what could possibly go right". IMO, a disaster waiting to happen.
Again this is a logical explanation
; there may be others.
To answer your earlier question of what should be done about it, I suggest nothing as I'm a great believer in letting the Darwinian Solution take it's course. Others are perhaps more caring; if so, then education is probably the most effective solution. Perhaps even this thread contributes in a tiny way.
Apologies to those still reading for long post