Next message: Lu Abel: "Re: Long and Time at Sea"
It can only be said that it takes quite a bit of discipline, not to
mention responsibility, for one to adhere to a rigid schedule of sight
taking if not obliged of necessity to do so. On extended voyages, when
following a great circle track, frequent fixes were considered necessary,
perhaps appropriate is a better term, to keep the vessel on track - thus
mini zing fuel expenditure and time enroute, and I am talking about
within a few miles of the track. It was quite customary for me to take an
average of from 10 to 14 sights a day to accomplish this end -
specifically 5-AM stars + 3-AM suns, crossed with the moon or venus if
available + noon Latitude + 1-PM sun to check on speed, again crossed
with the moon or venus if available + 5-PM stars. What others may or may
not do is purely their business, but at one time both commercial and
naval ships required performance. I am sure that otherwise, on a long
passage without expected navigational hazards, the major portion of the
passage could be made by DR, with but a few sights in preparation for
landfall.
Henry
On Mon, 6 Jun 2005 08:18:38 -0700 Lu Abel <> writes:
> Henry Halboth noted the tradition of 0800, 1200 and 2000 position
> reports to the captain of commercial and military ships, along with
> a
> tradition of a noon sun shot. I'm 100 years ago one could also have
> seen several sextants on the bridge wings of any such ship at dawn
> and
> dusk, trying to bring down as many bodies as possible to get a
> perfect
> "pinwheel" fix.
>
> These navigators had an awesome responsibility of keeping safe a
> very
> expensive ship with hundreds of people aboard, so I can certainly
> understand their meticulous behavior. They were also navigating
> large
> ships with long turning times and deep draft, so "whoops, there's a
> hazard, hard alee" wasn't an option as it might be on a smaller
> recreational craft
>
> A year ago or so someone told me (and, unfortunately, I don't recall
> who
> it was, so I can't go back for more details) that a recreational
> sailing
> magazine had polled recreational sailors who had made long offshore
> passages (including quite a few circumnavigators). Of those who
> regularly used celestial, the vast majority reported that they
> simply
> took morning, noon-ish, and afternoon sun shots and advanced the
> resultant LOPs. No star shots, no fussing at dawn and dusk, just
> the
> sun. While I didn't question my friend, I'd assume these folks
> might
> also take daytime moon shots.
>
> I suspect their theory was that in the middle of the ocean, knowing
> position to a few dozen miles was more than enough. I also note
> that in
> a bouncing small craft, taking a sight with any degree of accuracy
> is
> extremely difficult.
>
> Comments? Especially from anyone on this list who has made long
> offshore passages on a small craft?
>
