T&T: [Fwd: Re: Navigation compute rsystem reliability]

[Rod Mell]

Very good points Arild. It's essential to take everything on the charts 
with some skepticism and look out the window!  In close quarters try to 
always confirm what you are seeing on the chart with what your eyes and 
some common sense tell you. In general I have found the charts to be 
fairly accurate in the PNW and lower BC. But we often slightly alter 
course from our preplanned route when the little green boat on the 
screen isn't where my eyes tell me it should be. Now in Western Mexico 
with charts done in the 1800's we often found ourselves travelling over 
land. Sometimes had errors of almost 2 miles!

We also try to carry several guide books for the areas we travel in. 
They will often show rocks and other obstructions that aren't on the 
charts. We want as many inputs as we can possibly have - not just the 
electronic ones!

Stay safe.

Rod & Sandra
NiSa, Monk 34
Powell River, BC



----- Original Message ----- 
From: "Rod Mell" <nwboater at gmail.com>
> We often cruise in new areas with lots of small waterways and rocks and 
> feel this system gives us good backup and redundancy.


REPLY
There is one thing  most people  keep overlooking  with regards to these 
electronic navigation systems.
I see endless discussions concerning  fancy features and useful  add-ons 
like anchor alrams.
What I do not see is an awareness that  every national hydrographic offices 
are under fiscal restraints  and as a consequence  do  not perform as much 
field work as they once used to do.

Priority is given to commercial shipping routes, high traffic areas  and 
places where a grounding or worse, a sinking could cause major  upset to 
life ashore.  This is as it should be.

But recreational boaters tend to want to get away from it all and seek 
secluded anchorages  far from the maddening crowd and  busy  ship traffic. 
These are the areas  that get the very lowest priority  in  national 
hydrographic offices.  Chart data  is often not updated  for decades.
Companies  that provide electronic  chart data  get their raw source data 
from the hydrographic offices.  It would be  an astronomical expense if 
C-Map or Navionics  or Furuno  or whoever  actually went and did their own 
detailed surveyes of remote recreqtional anchorages and  byways.

In the old days of paper charts  the revenue stream from paper chart sales 
helped fund the Hydrographic Offices.  So where does the money come from 
when  no one buys paper charts any more?  Tax payers generally are demanding 
governments cut expenses wherever possible.

Garmin has evidently decided to conduct their own surveys of inl;and minor 
waters that were not covered by the National Hydrographic Office.   Good 
move.  But I continually hear  people complain  that Garmin proprietary 
chips are expensive.   Well gee!  Where do they expect the money to come 
from to conduct such surveyes if not from the sale of product?

So  give a thought to just how reliable the data itself might be, not just 
the  cocmputer displaying the data.

regards
Arild