How Do I Use Conversion Tables?

[kapitan88]

I put off downloading GWX for a long time but finally committed and I love it. Wish I had done it sooner. Being a newbie sometimes I chase down convoys and I am usually there when they are far gone.



I know the conversion tables are used to calculate how fast a ship is going and how fast you need to be to arrive just in time. But how do you use them in a step by step fashion? Them being in German doesn't help either lol.

[John Pancoast]

I put off downloading GWX for a long time but finally committed and I love it. Wish I had done it sooner. Being a newbie sometimes I chase down convoys and I am usually there when they are far gone.



I know the conversion tables are used to calculate how fast a ship is going and how fast you need to be to arrive just in time. But how do you use them in a step by step fashion? Them being in German doesn't help either lol.

The tables won't be much help without knowing how to plot an intercept. If you're not familiar with how to do that, this (https://www.subsim.com/radioroom/showthread.php?t=88961) is a good way though some steps can be omitted if desired. Steps 1-8 are the main part to know.

Once an intercept point is known, its a simple matter of using the tables to determine how long the target and how long your boat will take to get there.

[kapitan88]

The tables won't be much help without knowing how to plot an intercept. If you're not familiar with how to do that, this (https://www.subsim.com/radioroom/showthread.php?t=88961) is a good way though some steps can be omitted if desired. Steps 1-8 are the main part to know.

Once an intercept point is known, its a simple matter of using the tables to determine how long the target and how long your boat will take to get there.


Ok I think I understand.

[John Pancoast]

Give a yell if help is needed with anything.

[Pisces]

GWX has 2 tables:

knots (nautical mile per hour) to kilometer per 1,2,4,6,10 hours.

knots (nautical mile per hour) to meter per 1,5,10,15,30, 45 minutes.

Since you usually know the speed you or the target is going you look along that row.

Knowing the time you take the longest interval below it, then succesively add the largest smaller time intervals until you get to the desired time. (or take a larger interval and subtract a smaller interval if it is more convenient/ takes less than doing additions)

7 hours + 36 minutes = 6 hours + 1 hour + 30 minutes + 5 minutes +1 minute

So you add up all those distances from the same line and get your result of distance moved at that speed over that time.

Going back from a known distance, and a time to figure out a speed is not as simple. Consider the next way to solve either of 3 unknown cases:
It is much quicker to simply learn to use that nomograph on the navigation table. Draw a line across 2 known values in the time, speed and distance scales. Then the unknown value is crossed at the correct place.

And yeah, this doesn't help much in knowing which course to move to intercept the quickest. Dantenoc's guide (linked by John Pancoast) is good for that. And I figured out my own maneuvering sketch (https://ricojansen.nl/image/Dancing_around_2.gif)