(dumb question) how do i measure diameter of existing lines?

[bluecolumbia]

trying with a ruler and with a caliper but i'm having a tough time getting consistent results to the mm or 16th on old lines. what is a reliable strategy for determine the size of existing lines?

thank you...

[psk125]

Line diameters change as they are stretched and worn, so old lines can be hard to figure out. They could be thinner in some places and thicker in others. Plus, you don't know if they were in mm or inches to start with. One mm or 1/16" is not going to make that much of a difference if you are looking to replace them. Modern lines are usually stronger than they need to be because the bigger diameters are easier to handle, so that's what gets used.

[ggray]

With the caveats of psk, you might try measuring the circumference and divide by3.14159. A little more consistant than using a caliper.

[Jim Cate]

I have noted that new lines are not consistent in their measured diameter. Varies between brand and even within one manufacturer's product. Confusing!

One hopes that their performance does not vary as much as the diameter on the reel!

This observation does not help you with your measurements, but might ease your worries about discrepancies!

Jim

[Calif.Ted]

Some places will have a rigging calculator showing a recommended size and length, as others have noted some kind of change in Imperial/Metric sizing charts has been problematic. I used to use 10mm halyards on boat originally fitted with 7/16" (11mm) but recently 10mm has been too big for sheaves and have reduced to 8mm. Samson's website notes:

Diameters have been recalibrated for accurate metric sizing

https://www.samsonrope.com/recreational-marine/mlx3

There is a rigging calculator available at sailboatowners.com

[Minggat]

Professional Riggers Gauge

[Minggat]

Professional Riggers Gauge.
Mine says zarcor.com on it.

[Redline452]

Might the boat’s owner manual spec the sizes of lines? Alternatively, if you can identify the blocks and/or stoppers, they are rated for certain line sizes (or range of sizes) and are actually the key factor determining your choice of lines.

[guyrj33]

You could try putting some tension on the line before measuring it.

[basenay]

Zarcor.com website says product discontinued. Quick search does not find others-both DuckDuck GO & Goggle lead to Tension Gauges. Just curious what it looks like.

[Tom_F]

Maybe something like this would work? https://rwrope.com/products/cable-an...14090750689333

Tom

[garyfdl]

Lines? As in rigging, or as in plumbing?

That said, and in either case: go to the newest portion/section and measure there, take several readings with a caliper and average. That should get you close enough to figure it out.

If it's rigging, be sure not to squeeze/crush the line, and measure where the line doesn't go through blocks or sheaves.

[Calif.Ted]

Perhaps this will help, it's a general guide to sizes.
https://rigworks.com/wp-content/uplo...r-and-Type.pdf

[sasirles]

GG, I never knew you were a mathematician.

[Adelie]

GG???