Diving with measuring tape

[Sadamune]

I'm currently planning my mapping project for my Dive Master certification. I've decided that the kick-cycle method is too inexact for my purposes and that a more suitable method of measurement is needed. I've considered using a standard dive reel with increments graded on the line, but it occurred to me that the ideal instrument for measuring distance underwater would be the rather prosaic measuring tape. However, after a little research, I've not been able to find a measuring tape specifically designed for use underwater. There are a number of professional measuring tape reels made that are intended for terrestrial use, but I am hesitant to use one without some prior research to establish that they would work well underwater. So, I submit to the dive experts on ScubaBoard:

1. Does anyone make underwater measuring tape reels?

2. If nobody makes measuring tape reels for underwater use, what terrestrial models do most divers use?

3. What do underwater archeologists use when taking precise measurements?

I did locate a website that listed several terrestrial measuring tape reels (link below). Has anyone used any of these?

http://www.geodetic.com.au/category300_1.htm

Sadamune

 

[pir8]

I would use the reel

 

[Jake]

I've seen numerous people use measuring tapes underwater, though like you I'm unable to locate any online for that purpose specifically. The ones I have seen look a lot like some of the ones you've linked to. I don't know if they're exact models, but the style looks very similar. Good luck!

 

[Sadamune]

In my research, I recently found this website with some useful information about measuring distances underwater.

http://www-personal.umich.edu/~lpt/measure.htm

According to its author, Dr. Larry Taylor, conventional "surveyor's tape" may be employed to measure distances underwater. Alas, he does not specifically state what model he uses.

Sadamune

 

[archman]

Sadamune's correct, we use standard surveying tape reels, specifically the ones with the plastic handles. The only things that rust out on these babies are the screws and the little metal doohickie at the end of the tape line. Rinsed, dried, and stored properly after use, these things will last you a few years of underwater use.

Environmental field science and limnological supply catalogs stock them. Here's a link to some nice models sold by Wildco. I've got two of these things for use in my teaching lab.
http://www.wildco.com/vw_prdct_mdl.asp?prdct_mdl_cd=7900K

 

[Sadamune]

Cool, thanks for the link archman! It appears that fiberglass measuring tape in the form of "surveyor's tape" is the adopted standard for underwater measurement. I find it strange, however, that manufacturers of this kind of equipment haven't made a variant specifically for marine use, considering how simple it would be. All one needs to do really is just replace the cheap screws and claw at the end with inox versions and voila, instant "marine grade" measuring tape! I'll continue my search for a surveyor's tape reel that meets my criteria for underwater use, but at least I know I'm on the right track. Hmmm, I wonder if it would be possible to replace the screws yourself...

BTW, a UK company named "Draper" manufactures a surveyor's tape reel with a stainless claw. --> http://www.draper.co.uk/Pages/Pagesource/p252.pdf

Cheers,

Sadamunne

 

[archman]

The screws aren't a big deal; it's more of a "cosmetic insult" when they start to get rust on them. They'll still hold your reel together just fine. I've yet to see any UW archaeologists or UW surveyors perform any rust-preventative on their reels other than dunking them in freshwater. But they do that liberally.

Some people (me) often pull out the whole transect line, dunk it in FW, and let the whole strung-out line dry out before long-term storage.