NavList:

I agree, this is what I wrote back in 2009:

 

 

"Ken, maybe we see the word "backup" slightly differently. My suggested method was meant for those who already know celnav, it was not meant to be "Celestial Navigation For Dummies" a self teaching book. I meant it for a navigator who was considering whether it was worth the bother anymore to carry the sextant, requisite tables (H.O. 249, H.O. 229, etc.) and to remember to get a new Nautical Almanac every year (may be difficult where you are) or just give up celnav and buy an additional GPS to use as a backup. The flat Bygrave allows a navigator to decide, that without having to allow shelf space for books he will probably never use and not having to remember to get any almanac except once in every ten years (that can be downloaded for free from the Government web site,) he will just go ahead and keep that old sextant and these couple of pages and forgo spending money on that additional GPS unit. Especially since an additional GPS doesn't offer complete redundancy since the whole system could be made unavailable by some military action or by our government shutting it down at the most inopportune moment in order to deal with an enemy attack or terrorist plot. Celnav, on the contrary, does supply complete redundancy and is self contained needing nothing from the outside except a hole in the clouds. Or the flat Bygrave could be used as the primary sight reduction method for a sailor who practices celnav regularly but appreciates the reduction in storage space and hassles of obtaining Nautical Almanacs each year. The accuracy of this method is perfectly adequate for normal celnav and is about the same as that obtained with H.O 249 a popular method used by small boat navigators. Call it a "compact" sight reduction method instead of a "backup." For anybody looking for a compact method and who doesn't like the flat Bygrave I would recommend getting a copy of Weems Line of Position Book or Dresionstok (each are easier than Ageton) to replace their H.O 229, H.O. 214 or H.O 249 and then to also use the long term almanac from H.O 249 that I included with the flat Bygrave."

http://fer3.com/arc/m2.aspx/New-compact-backup-CELNAV-system-LaPook-apr-2009-g7908

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From: Greg Rudzinski
Date: 2015 Jul 14, 12:57 -0700

Gary,

I am with you on what is possibly being labelled as emergency navigation only. Compact/Ultra Compact doesn't automatically classify a method as being practical only in an emergency. There is perhaps a grey area where a method isn't quite good enough for everyday use on a ship but good enough for small craft. For me the line is drawn at 2' of precision for everyday use on a small craft and 1' of precision for everyday use on a ship.  Emergency precision should be no worse than 10' which is about the width of a pencil line on a pilot chart and about the distance to the horizon from the bridge of most ships. 

Ship/ Small Craft  Primary CN SR Methods:

1. Calculator, 229  (0.1')

2. 208, 211, 229 Schlereth, Weems, Hav Doniol, Original Bygrave, 249 (1.0')

Small Craft Primary CN SR Method:

1. Flat Bygrave (2')