NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Averaging sights on commercial vessels
From: Alexandre Eremenko
Date: 2004 Oct 7, 13:59 -0500
From: Alexandre Eremenko
Date: 2004 Oct 7, 13:59 -0500
Dear Doug, Thank you for your explanation on how Cel nav is practiced on modern merchant vessels. I suppose they took it much more seriously in the pre-GPS era that is 20 years ago. A Russian manual (for merchant mates) of early 1970 recommended 5 observations per day if conditions permit. And averaging 3-5 altitudes for each observation. As I understand, before GPS, Cel Nav was the most precise available method of determining position in the open sea, superior to radionavigation. Alex. On Thu, 7 Oct 2004, Royer, Doug wrote: > Alex, > You can,for all practical reasons,discount that averaging sights are the > standard proceedure onboard Merchie vessels in this day and age. > By this I mean the duties of the nav watch are such that having this as a > standard proceedure is not practiced.The nav watch is more concerned with > navigation,chart position and collision avoidance by useing radar and > sonar.The nav watch on commercial vessels usually consist of the OOD(3rd > officer or above), 2 but usually 1 ABS ratings on duty(all officers must > also be rated as ABS,so usually only 1 ABS and 1 officer are on the bridge) > around the bridge area and 2 S ratings on forward and/or roving > lookout.Conditions will dictate how many are called to nav watch duty at a > given time.On most merchies I doubt seriously if any celestial sights are > taken on a daily basis.The company I used to work for left most of the > operating proceedures up to the master.Some masters I've served with > required at least 1 sight be taken and LOGGED each 24 hrs while others had > no such requirement. > We would have training schedules for all personnel intrested in learning cel > nav and other aspects of navigation but these were,for the most > part,conducted on their off duty hours.Averaging sights is taught(especially > when an inexperianced member is practicing to become proficiant with the > equipment and reduction proceedures)and used when practical.Only if a rating > was rated for standing as a member of the nav watch would we have on duty > training in the cel nav and other disciplines so they could become > proficiantly skilled to meet the standards set by the company and Coast > Guard to advance.One was taught and trained(through repitition,trial and > error)to become proficiant in taking 1 cut and 1 cut only in a sighting > session.This takes time and practice.Not always the most accurate method > even by officers but duties elsewhere leave not much time while on watch > because of the reduced number of crew personnel onboard.The reliance on the > interpretation and use of electronic postion finding equipment is paramount > on today's merchy vessels. > Even though the Coast Guard requires each vessel to carry the needed > equipment AND have as a crew's complement people who are proficiant in > position finding by celestial navigation it is not practiced on a scheduled > daily basis throughout the industry today.It is practiced,for the most > part,now as a matter of professional pride for both officer and rating. > > Joel,thanks for shareing the pictures of the Vero Beach area.That will give > us all a glimpse of the power,especially in the dangerous quadrant,of > typhons or hurricanes. >