Parallel rule/distance question

[flee27]

To those smarter than me... when measuring between 2 points on a chart that is longer than my parallel rule is there a trick other than grabbing a longer ruler to connect the dots?

Thanks for the help

Foster

[kenbo]

If you have a pair of dividers, set the dividers to a known distance on the chart's scale and "walk it off" by going point to point.

https://www.youtube.com/watch?v=cbTyE_D1KJw

[flee27]

I am trying to draw the course line to measure degrees on the compass rose. I can’t connect the dots with the parallel rule. I did it with a yard stick but was curious if there is a trick using normal plotting tools.

Thanks

[belizesailor]

If I understand your question, you can "walk" parallel rulers all over a chart regardless of how far apart the points are located. This is their purpose...to move a line parallel to the original to another point on the chart. For example, from a course line to the nearest compass rose.

A good demostration here:

https://youtu.be/xKSBYfscA80

You can use a similar technique to extend a line or connect two points which are seperated by a distance longer than the parrallel ruler.

[Snore]

The only ways I know to make sure your course line intersects the two dots are

a) the obvious- use a longer straight edge or

b) a second ruler/straight edge that is placed such that the two rulers overlap for about 3”. This effectively lengthens the original ruler.

[flee27]

Thanks for all the responses. I guess I am not asking my question clearly. I understand walking with the parallel rule. My question is not as much for practical usage but for testing. With testing, the answer (as I understand) have to be within 2 degrees. I don’t feel like I can guess the angle between 2 places at opposite ends of the chart and walk the line accurate enough to be with in 2 degrees.

[flee27]

Thanks snore. That’s all I could come up with. Was thinking there might be some trick I was missing.

[SVHarmonie]

A "trick" that has almost always worked for me: Use the edge of the chart. It's straight. Just use the edge of the paper to extend the line of the rules. It is always there...

Depending on how you fold/roll your charts it might not work for you, but it is one I keep in my back pocket for those long course or bearing lines.

[belizesailor]

Originally Posted by SVHarmonie

A "trick" that has almost always worked for me: Use the edge of the chart. It's straight. Just use the edge of the paper to extend the line of the rules. It is always there...

Depending on how you fold/roll your charts it might not work for you, but it is one I keep in my back pocket for those long course or bearing lines.

You can also use this trick to mark some intermediate points and then walk off and draw a straight line w the parallel ruler.