Originally Posted by Bulawayo
I apologise to you....I didnt realise you were so perfect and that you carry so many charging
systems that are lightning
proof AND that you also carry a dozen GPS's (why?). I dont accept that most cruisers carry so many charge devices either - maybe where you cruise
but not from the interaction I have with cruisers - rarely do they have the four you mention. One person breaking a mirror doesnt make it a common issue for sextants either. Its not that you might loose every GPS
device on board, it is the practicalities of subsequant action when many do not know even how to run a DR plot or have a small scale chart on board. There are so many misconceptions about basic nav skills as has already been demonstrated by some people with obviously no practical knowledge and no real experience. On that point you could be correct as those people will never really be mid-ocean so shall its not relevant!!
I really recommend you research
modern technology before playing the luddite. Just about every piece of electronics
that you buy has a GPS
in it that operates independent of land based systems.
As far as your responses:
- Even the most navigationally challenged cruisers will have at least a rough idea of their starting point if they have been running the chart plotter all along. In addition, they likely have a pretty good idea of challenging areas on their intended course, so starting position it's really a big issue.
- The first and most important navigational challenge is how to determine a heading. Yeah, a lighting
strike can throw off a compass
but as demonstrated, there are a number of methods to determine direction without a deep understanding of sextant
based celestial navigation
. Once you know what compass
reading correspond to the cardinal directions, the compass retains pretty much all of it's original usefulness. If east corresponds to 164 degrees and you want to head
east, simply take up a compass heading of 164 degrees.
- With at least a half dozen GPS units, you don't need to turn them all on and run them till the batteries die. In the event of loss of power, turn them all off and only turn them on for a couple of minutes to get fix. This should give you weeks if not months of position fixes and those fixes will be an order of magnitude more accurate (on the order of feet as opposed to miles).
To clarify, my objection is not with understanding navigational techniques (as the title of the thread implies). My objection is the immediate descent of the thread into the assumption that the only reliable means of navigation
based celestial navigation
. If you want to take up the sextant as a hobby, more power to you but modern electronic navigation
is more than reliable enough to be a replacement.