waynes said ...
There is no viable alternative offshore other than celestial,
and even the Navy has stopped teaching it.

waynes i'm guessing that you mean that the navy doesn't teach RDF, not
that they don't teach celestial. only reason i say that is because it
seems like the military would need backups like celestial because i
understood that the EMP from a nuclear weapons blast could take out
electronics such as GPS systems. is that wrong ? i'm surprised that
someone in the navy who was going to navigate such important ships
would be able to get out of their training without knowing absolutely
every way there was in the world to navigate. it seems like a navy
sailor would have to know everything there is to know about navigation
before they could make decisions that affect the ship.

da kine said ...
GPS is great right up until you get a lighting strike and
everything blows out.

thanks da kine and everyone for the great posts. i want to know as
much about navigation as i can and really enjoy learning about all
these alternatives. you mentioned some others including cloud
formation, wind direction, wave intervals, etc, and i hope things like
that get mentioned in the two fat navigation books i'm currently
reading.

i wonder what other situations could lead to GPS not working ? i'm
with everyone else who thinks that GPS with some spares is really
important. i agree relying on just a GPS wired into the boat is a bad
idea because what happens if it stops working, or if your boat
batteries die, or you just forget to bring enough fuses or something,
or your power generation methods fail. i can't really think of much
that would stop a handheld unit from working except for
losing/destroying them, not having batteries, etc. i wonder what
situations outside of a sailors control could make GPS fail ? i mean,
i assume because so many people rely on GPS that the military wouldn't
just shut it off unless there was some really drastic reason for doing
so. i've read that they might make it more inaccurate or shut it off
in the event of war, would they ? and i assume too that they take
really good care of it since they and everyone relies on it so much ...
has it ever failed ?