That's why the tape is for sale on ebay; it's no longer useful to the owner.
@jaro?ÿ Nah, it would be an international nautical foot. ???
If its got a rogue scale, it might stop others from borrowing it, like those pesky surveyors.
British fathom
The?ÿBritish Admiralty?ÿdefined a fathom to be a thousandth of an?ÿimperial nautical mile?ÿ(which was 6080?ÿft) or 6.08 feet (1.85?ÿm). In practice the "warship fathom" of exactly 6 feet (1.8?ÿm) was used in Britain and the United States.?ÿNo conflict in the real world existed as depths on Imperial nautical charts were indicated in feet if less than 30 feet (9.1?ÿm) and in fathoms for depths greater than that. Until the 19th century in England, the length of the fathom was more variable: from ??5?ÿ1?2?ÿfeet on merchant vessels to either 5 or 7 feet (1.5 or 2.1?ÿm) on fishing vessels (from 1.7 to 1.5 or 2.1?ÿm).
@richard-imrie Your first part of the reply seems the most plausible as the spacing doesn't exactly fit any standard measurement system. However, as Bill notes the fathom scale would be a definitive deal breaker. As a lifelong mariner, no one would ever use a steel tape for soundings on so many levels. The only time I have used steel tapes for soundins was when I worked on oil tankers, we would use conventional (Imperial) steel tapes to sound the tanks for both innage and ullage readings. I would assume my Euro counterparts would do the same with Metric tapes.
Measuring the depth of water bodies is always done with a sounding lead attached to a cotton or synthetic line.
I think it would be a nautinational footsie.
So after a lot of research- rj-schneider was correct-?ÿ I received more information from the seller, and that helped me to determine that this is a 2-chain ?Topographic Trailer Tape? -or "Slope Tape"-?ÿ basically?ÿ a modified version of a normal 2-chain steel tape, with an extra ??TRAILER? section of tape that has the extra-length divisions that allow one to measure the slope distance but determine the equivalent horizontal distance at the same time, without having to perform any actual slope calculations.
-This found use in the forestry service, to help measure steep terrain in the field without the need for slope calculations, using an Abney level (which was essential to use this tape)-the marks on the trailer tape segment correspond to extra slope distance per foot of vertical rise over 1 chain (66feet), which is available as a topographic scale , or "Topographic Arc" on some Abney levels )- using the Abney level, measure the slope, using the "topographic scale" -?ÿ then adjust the chain/ or read the chain at the corresponding Mark; you have now measured off the a slope distance equal to the 2-chain distance in the horizontal (132 feet).?ÿ see the attached diagrams and document.
Note, even though the topographic scale on the Abney level indicates rise in feet over 1 chain (66ft);?ÿ The trailer tape accounts for this and is marked correctly for the regular 2-chain length (132 feet).
(The Topographic Arc Reading of "10"?ÿ in the above diagram is the "Mark" on the Trailer tape portion, equal to the vertical rise over 66feet as measured on the Abney level)- this is showing a slope of 10:66ft,?ÿ?ÿ or 20feet higher at the end of 2 chains (132ft).
I've included a little write up with a table of all the actual Trailer-tape marks, slope-distance lengths, and the corresponding distances between the Trailer-tape intervals. See attached document that I put together:
?ÿ
The following references proved helpful with diagrams and descriptions of how this Slope Trailer tape was used
?ÿ
??The Surveying Handbook?, vol 1, copyright 1985, by The Surveying Handbook, ?ÿWalter G. Robillard (auth.), Russell C. Brinker P.E., Roy Minnick L.S., R.L.S. (eds.)?ÿ publisher: Springer US
The Abney Level Handbook, 1927,?ÿ US Gov??t Printing Office, Forest Service, by A. Calkins and?ÿ J.B. Yule, US Forest Service
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So we weren't given the whole picture, and most of us assumed all numbered divisions were equal in length. Can't reach a good conclusion without all the relevant evidence.
@bill93,?ÿ Yes, the seller didn't realize the divisions weren't equal either... understandable, as I've never seen a slope tape either- and every other steel tape I've seen had equal divisions.?ÿ?ÿ The seller did actually did unwind the tape inside his office and got back to me with the actual measurements- which pointed me in the right direction to confirm what this was.?ÿ?ÿ I can understand, I wouldn't have known what I was looking at either to begin with, and most of us don't wish to unwind a steel tape that's not on a spool if we can avoid it.
The red 1 is 1 foot. the upper graduations are .01 ft. (We use to joke they were long inches) and the lower graduations are at 1/16 of a ft.
oops that should be 1/16 of an inch