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Thread: Navigation question

  1. #1

    Default Navigation question

    Hi All,
    I am trying to learn basic navigation and I have a grasp on dead reckoning so far. Now I am trying to wrap my head around estimated position and I am coming up against set and drift.

    My question is how do I calculate the effect that wind, tide, tidal current have on my boat? I need to be able to calculate the difference between where I think I am (DR) and where I really am (EP).

  2. #2
    Member bhollis's Avatar
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    Get yourself a Chapman Piloting. It has an extensive section on piloting and navigation.

    However, the concepts you're talking about--dead reckoning, set and drift, etc.--are really most pertinent to offshore navigation, where you don't have landmarks to use to fix your position. For most of us, who operate near shore, the best way to determine position (most often in combination with a gps unit nowadays) is by comparing the landmarks and aids to navigation we see outside the window, and the soundings we're getting on our depth finder, with what's indicated on our nautical charts.

    This isn't to say that you shouldn't bother with learning about traditional navigation techniques, but rather simply an acknowledgment that for near shore operations, with gps units available for only a few hundred dollars, you won't find many recreational boaters running a dead reckoning plot and computing set and drift these days.

  3. #3
    Member Alaska Gray's Avatar
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    Quote Originally Posted by FbksFishinFool View Post
    Hi All,

    My question is how do I calculate the effect that wind, tide, tidal current have on my boat? I need to be able to calculate the difference between where I think I am (DR) and where I really am (EP).
    Experience..... Boat size, weight and how tall the boat is all play a factor in your drift. Keep a log of the wind, weather, seas, and tide change +/-, If you have a gps log the speed your drifting, how far and how long it took you.

    After a few times you will figure it out.
    Living the Alaskan Dream
    Gary Keller
    Anchorage, AK

  4. #4

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    I know what you are saying bhollis....I am beginning to wonder if I am overcomplicating this whole thing myself!
    Basically, all I can see me doing for the forseeable future is fishing in Valdez, Seward, and possibly Homer. Fishing along with a little exploring so I can keep up with conversations when I hear someone say "the fish are really biting at_____"
    I want to be able to do some salmon, halibut, rockfish fishing, try some shrimping, and maybe visit Cordova. I seriously doubt I would be travelling much more than 100 miles at any one trip.
    So open ocean navigation is not a real concern for me. I am a harbor rat for the most part! And at the most a bay rat! I won't be too far from any shore.
    But that's not to say I don't want to learn SOMETHING about navigation...I won't be getting into celestial navigation (this is Alaska after all - we don't have a celestial in the summertime!) but dead reckoning might be handy to know should my electronics go beserk!

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