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    Re: SOA vs SMG or SOG
    From: Greg Rudzinski
    Date: 2009 Oct 23, 16:33 -0700

    Irv,
    
    I will quote Bowditch vol. 1 edition 1977 page 61 "The expression
    speed of advance (SOA) is used to indicate the speed intended to be
    made along the track, and speed over ground (SOG) the speed along the
    path actually followed. Speed made good (SMG) is the speed along the
    course made good." I never used the acronym SOA in my merchant days
    but it does appear to have applications when diverting for weather,
    rescue, or rendezvous. The terminology conflict is that the word
    ADVANCE is used to describe two very different actions regarding ship
    movement.
    
    Greg
    
    On Oct 23, 1:42�pm, "Irv Haworth"  wrote:
    > Hi Greg
    > Yes I'm familiar with the ships �"advance" , etc as posted in the bridge.
    > Unfortunately I �do not understand your last sentence. ( To me SOA means on
    > a normal DR plot , the intended speed required...whereas SMG is the actual
    > speed achieved from point A to B ) Given this I need another few words to
    > clarify ..."terminology conflicts". please
    > 73
    > Irv
    >
    > -----Original Message-----
    > From: navlist@fer3.com [mailto:navlist@fer3.com] On Behalf
    >
    > Of Greg Rudzinski
    > Sent: Friday, October 23, 2009 11:59 AM
    > To: NavList
    > Subject: [NavList 10261] Re: SOA vs SMG or SOG
    >
    > Irv,
    >
    > Advance refers to the distance a ship moves forward during a 90� turn at a
    > specified rudder angle. Advance, transfer, and other ships characteristics
    > are posted on the bridge as per CFRs. Using SOA in place of SMG would lead
    > to a possible terminology conflict.
    >
    > Greg
    >
    > On Oct 20, 6:24�pm, "Irv Haworth"  wrote:
    > > I'm somewhat perplexed over current usage of abbreviations: to wit the
    > > old (last 25 years ?) �standard meaning of SAO (speed of advance)
    > > versus what �I believe is the current view as presumably held by WMO
    > > (World Metro Org. ) who supply ships with free equipment and training
    > > to report weather..VOS (Voluntary Obs ...) What follows is an slightly
    > > edited (name of ship etc removed by me) recent report.
    > > The noon to noon report based on positions shows 425 NM ( my Rhumb calc.
    > > gives 424.5 NM) which they report as a SAO of 17.7 kts.
    > > To me the SAO should more rightly be termed the SMG (speed made good) .
    > > I contacted the webmaster but despite being an old US Navy chap had no
    > idea.
    >
    > > Hopefully some members might shed some light on matter for someone who
    > > may have slipped a notch or two without realizing the new
    > > movement....hi..hi himself aka Irvin
    >
    > > Last reported at 2009-Oct-19 12:00 UTC. Time now 2009-Oct-19 18:30 UTC.
    > > Position
    > >  > .2&lon =-179.7&radius=300> S 17�12', W 179�42'.
    >
    > > Wind from 160 at 14 knots
    >
    > > Waves 1.0 meters (3 feet), 10 second period
    >
    > > Barometer 1012.0 mb
    > > Air temperature 25.0 � C
    > > Dewpoint 19.1 � C
    >
    > > Notes � �date/time � � � lat � � lon � � naut. miles run � � � � SOA
    > > wind from � � � �knots �barom. � wave height � � air temp � � � �dew
    > > point water temp
    > > � � � � 2009-Oct-19 12:00 � � � �S 17�12' � � � W 179�42' � � �425
    > > 17.7 � � 160 � �14 � � � 1012.0 �1.0 � � 25.0 � �19.1
    > > � � � � 2009-Oct-18 12:00 � � � �S 15�00' � � � W 172�42' � � �50
    > > 16.6 � � 120 � �12 � � � 1010.2 �1.5 � � 26.0 � �21.8
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