Dee:
Thanks, Doc.
There was a guy there last year who had taken short pieces of one of those pool floaties and wrapped them around the strobe arms on his camera rig to offset the weight. He was a great hit with the parrotfish in the front yard. They are so used to divers, they would go to him and taste his floaties. Needless to say by the end of the week, there wasn't much left. Luckily the parrotfish would spit out the pieces but they kept trying!
Every time we come up with some experimental form of long term "float" marking device for use by SCUBA divers, it always looks good on the work bench- but after a while underwater....
The idea here is to solve the problem of underwater "nature trail markers". The best one I've seen is in Belize where they have erected plastic placards avery 150' along a sandy bottom. That costs big bucks. We were looking for something simpler, cheaper, and more available to Dive Clubs that want to enhance their favorite dive sites. Sometimes, simply aiding in navigation for short traverses is important.
The short term stuff is easy. Anything will last a day or so- the only trick is to make it visible as a marker and make sure that it doesn't get loose or pollute.
This is a great tip for Bonaire (or any shore dive). Always take a two liter pepsi bottle (not much air in it) and 15' of light string and a 2# weight. On your way swimming out- place this in maybe 25fsw and turn into the current for your shore dive. Upon your return in 25fsw, you'll find your parked car pretty easily. Otherwise you're lost.
Long term? We've tried DOT approved reflector tape- the expensive stuff you see on big rig trucks. Something eats it. Laserfoil holographics- no, bicycle reflectors- no, and on and on.
The best long term items so far seems to be 1/4" yellow poly braided line (not hollow core) knotted and passed thru a hole drilled in the screw top of a .5 liter water bottle, as in your picture above. Finding a piece of dead coral to tag it off to can be quite time intensive.
Simply running a long length of cord from point to point, supporting it in the middle with float bottles seems to work as well. There is a publicly visible example of this at CCV between the PA Wreck, the DC3 and Newman's Wall.
Many local photographers rip these out as they detract from photo opportunities. They also know the area intimately so they assume that visiting divers have the same comfort level. One man's vandal is another's eco-terrorist. So it goes.