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Tuesday, 8 May 2018

Gridded Naval Wargames book: More explanatory diagrams

I needed to explain how I have used a 3:2 ratio for ships moving diagonally on a squared grid. In other words, that for every three grid areas the ship could move orthogonally, it may only move two grid areas on a diagonal course.

(Note: On a grid, all counting is done from the centre of one grid area to the centre of another grid area.)

The 3:2 ratio is relatively close to the ratio between the hypotenuse of a right-angled isosceles triangle and the other two sides. In other words, when the length of the non-hypotenuse sides of the right-angled isosceles triangle is 2, then the length of the hypotenuse is 2.83 (i.e.√((2 x 2) + (2 x 2)) = 2.828 ... which is close to 3).

The geometry behind this can be shown thus:


I hope that this is much clearer in the following diagram:


(The original diagram I designed looked like this ...


... which I though was less than helpful in trying to get the concept over!)

10 comments:

  1. This comment has been removed by the author.

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    1. Stu Rat,

      It is what I thought you meant. I think the diagrams explain it better than my written explanation did.

      All the best,

      Bob

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  2. Hi Bob,

    There is a really simple trick for handling gridded playing surfaces and the issue about orthoganol and diagonal movement. In Peter Pig's PBI the rule is one diagonal movement for very two orthoganol moves. I think this is really neat and keeps things simple for old people like me. Love what you are doing with the portable wargame stuff. Good work!

    Cheers

    Jay

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    Replies
    1. Old Trousers (Jay),

      Thanks very much for your comment, I like many of the concepts incorporated in Peter Pigs rules. (I've known Martin Goddard for a long time, and over the years I have seen quite a few of the early drafts of his rules.)

      Keeping things simple is one of my main wargame design principles ... and it informs all the design decisions I have made when developing the PORTABLE WARGAME rules.

      All the best,

      Bob

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  3. That was the basis of my article about a year ago on movement and ranges on square grids.
    https://archdukepiccolo.blogspot.co.nz/2017/02/measuring-shooting-ranges-on-gridded.html

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    Replies
    1. Archduke Piccolo,

      I've just read your February 2017 blog entry ... and for some reason I cannot recall ever reading it before. It certainly does covers this topic, and explains it in a very simple and straightforward way.

      Thanks very much for bringing it to my attention.

      All the best,

      Bob

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  4. and presumably there is a rule that you can't move along the diagonal if both squares forming the angle are blocked?

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    1. Ross Mac,

      If I've understood your question correctly, the answer is 'Yes', the rules should not allow it.

      All the best,

      Bob

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    2. A very pertinent point. Certainly one ought not to be permitted to shoot though that corner/angle. Movement seems to bear thinking about (you know, the infiltration thing) but on reflection, I agree. If both squares flanking a corner are occupied, the gap is too narrow - effectively a point - to pass through.

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    3. Archduke Piccolo,

      It certainly seems to make sense to me ... and pushing some toys around on a grid seems to bear it out.

      All the best,

      Bob

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