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    Re: Hello! Is there anybody out there still working on the Silicon Sea Problem Legs?
    From: Mike Burkes
    Date: 2009 Jun 12, 12:47 -0700

    H Bill and Peter, yes some of us are still working SS!! Via my SS
    notes Dan Hogan's email(s): dhhogan{at}concentric.net
    and
    dhhogan---.com. West Covina, CA, is Dan's residence very close
    to mine. HTH.
    Mike Burkes
    626-833-1521
    
    On Jun 9, 10:18�am, wjlub...---.com wrote:
    > Two months ago while while surfing the net looking for information to 
    supplement my books on navigation, I found this site and the very useful 
    downloads available on it. The Silicon Sea problem was just my thing. I am 
    impressed with the amount of research, work and effort that went into 
    creating it.
    > �
    > Us landlubber arm-chair navigators seldom get to breath the salt air or feel 
    the green water spray over the bow. This at least gave us the opportunity to 
    remember it. Ten years after you created this adventure, my cruise left�Palma 
    de Mallorca.�I have been working the legs and now find myself ready to leave 
    Rio de Janerio and start leg 61.
    >
    > �
    > A couple questions, yes I have many!
    > (1) Often wind force is listed. It is stated as: "Wind is force 4 from 175 
    degrees." I have been multiplying the average speed in knots by a factor 
    (0.02) to get the current drift and rotating the direction for Coriolis by 30 
    to 45 degrees when the latitude is at least 30 degrees from the equator. Is 
    this the intent of the problem? Or, should I just be using the given wind 
    direction as the set?
    > �
    > (2) Often current set and drift are given. Is it your intent that this be 
    included with course and boat speed as a known condition in the computation 
    of a DR position. In the notes, it stipulates that only estimated position 
    (EP) should include DR+current effects. I have seen it done both ways.
    > �
    > Is their any errata out their for the legs or answer sheets? I have run 
    across what appears to be typos in the on-line material. The answer sheets 
    are great as they really make you work to get the listed answers. �
    > I have had my share of problems and misunderstandings of the instructions 
    but have persevered. Needless to say, I have had to do a lot of review and 
    learning especially of the sailings. My answers do not necessarily correspond 
    to those given in the answer sheets but most are close. I would like to share 
    them with any one interested. No guarantee that my answers are�correct. 
    Converting zone time to universal time and back over several time zones has 
    been a challenge.
    > �
    > My methods of solution:
    > Celestial observation:
    > For most legs, I have used HO229 and Ageton for astronomical position with 
    backup from a HO214 program on my HP34C pocket calculator and Omar Reis's 
    Navigator program which I have a registered copy. Plotting is done with 
    plotting sheets downloaded from the Navigation -L site.
    > �
    > The sailings:
    > Rhumb line navigation is done with mid-latitude sailing or Mercator sailing 
    with backup from a Rhumb line program on my HP35S. Great circle sailing is 
    done with Ageton's tables or calculation,�with�backup from a great circle 
    program on the HP35S.
    > �
    > Questions involving current set and drift, true course to steer, cc/CTS�etc.:
    > Solution has been by calculation�or graphically�with maneuvering board 
    sheets downloaded from the Navigation-L site.
    > �
    > I understand that using a pocket calculator or worse a computer is 
    disgusting, or at least probably not reliable at sea, but they are great 
    checks on the work.
    > �
    > I have been reading a lot about slide rules�in the forum. I own a Post 
    Versalog�(Log Log Decitrig, 23 scales)�slide rule, which I made my living 
    with for 15 years. I put it on the shelf after buying my first HP calculator, 
    an HP 45 in 1974-75. It did polar to rectangular coordinate conversion which 
    saved a lot of time. I still use the Versalog occasionally just for fun. It's 
    as accurate and readable today as the day I bought it in 1957. The Versalog 
    had a magnifier but it has long since disappeared. Most work we did in those 
    days, away from our desk,�was done with a 6" plastic (often cracked) slide 
    rule some vendor gave us. It worked fine before the pocket calculator became 
    available. Enough on slide rules.
    > �
    > Thanks guys, looking forward to hearing from you.�
    > �
    > Bill Lubitz
    > �
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