The reason why that coil isn't waterproof is I suspect (never had one) that, being a solid DD coil, it probably isn't filled with epoxy in order to keep the weight down. Does the coil feel "mushy" when you squeeze it? I owned two different new Hot Shot coils, which were 12" concentric coils, that I tried on my QXT Pro for more depth...As those were/are the only larger coils for the low frequency Whites machines, besides a 14 or 15" coil that Whites made but I heard was too big (being a concentric...DDs can get this big and still have good coin sensitivity) to have good sensitivity at depth for coin sized targets.
Anyway, the first Hot Shot (A jimmy Serria product) coil I tried worked well for about ten minutes, and I instantly dug a couple deep mercs that I knew should be present at this particular spot. Needless to say I was excited beyond belief, until after about ten minutes the coil started falsing badly like the sensitivity was too high. I thought perhaps some EMI noise was in the area now and so moved on to another site a short drive away that was more secluded and shouldn't have any EMI problems. Once again the coil worked great for about ten minutes, and then would once again false like mad and make the machine go crazy. After several more attempts to use the coil at different spots this continued to happen. It worked fine for about ten minutes and then went crazy. The curious thing was if I turned the machine off and back on it was still going bonkers, but if I traveled to another site it would once again work fine for about ten minutes.
I finally sent it back and got another new Hot Shot coil. Nightmare of nightmares, this coil did EXACTLY the same thing after about ten minutes, so I sent it back. For years I scratched my head on that mystery until one day it hit me....The coil was mushy when you squeezed it, as being a solid coil it wasn't filled with epoxy to hold the windings tightly in place. Keeping the windings of the coil in strict alignment with each other is very important. Then I knew why this coil was white...They made it white to try to keep it from absorbing too much sun, because when he heated up in the sun the windings would move and it would get unstable.
Now, everything I've read about that Coinsearch coil says it's a great coil and doesn't have any such issues, but I suspect (?) that being a white coil and not waterproof it might not be filled with epoxy, which means....No, it's not waterproof. On the other hand, I think I remember reading about somebody a few years ago saying he hunted in the water with this coil without issues. If I remember right I think he said he put shoe goo or some other sealent under the coil nut and then tightened that down by hand, then turned it just a tad more with a wrench to make sure it was water tight. That being said, if that coil is hollow inside then any small pin hole in the casing means it'll be lights out if you use it in the water. I wouldn't. I seem to remember that the person complained that the coil would try to float too, probably because it was hollow inside, and having used a 6" Whites coil in the water that was also hollow and so tried to float, and I can tell you that it's a major pain in the backside to constantly have to push down hard on the coil to keep it under water.
As far as hunting wet grass goes, I don't think you'll have a problem with that...Unless there is a hole in the bottom of the coil that lets moisture in.
