Headed off to do a mid day water hunt with a friend who has an Excal. The back extension I'm using at 23" long at roughly head height in normal hunting postion doesn't give me much confidence to go much past my belly button. Too much paying attention that I'm not lifting the coil and dipping the control box too low. I could probably go niple deep but just don't feel comfortable doing that, so until I get a $20 Plano box to throw the control box in quickly for water hunts, I ain't going deeper. I feel no more confident going any deeper than I did with the GT chest mounted high near my upper left chest out of the way, even though on the extension it's at head height.
I still will use the extension though when I get that Plano box, just so the Plano isn't trying to float or drag in water, and also so that even at top of the shoulder depth it's still out of the water a bit, giving me extra confidence no leak should matter should one be present in the box.
I will say though that mounting the box in a sealed plastic bag on this extension does make me feel more "free" not having the box chest mounted, but at the same time I felt no more confident to wade deeper than I do with the box high upper left chest mounted in the Minelab bag.
For sure if I was to go deeper it's very important to keep your front of your foot on the coil when using your right hand to leave the grip and pick the target out of the basket, because at say near shoulder height depth any slight lifting of the coil when you take your hand off the grip could get the control box dangerously close to the water.
Even though I have it seemingly sealed water right in the bag, I just don't feel that extra ounce of "freedom" by it being sealed in that and mounted at head height while in normal hunting position. At least with it high chest mounted I could look down and see how much water clearance I had to the bottom of the chest mount, but with it on the back extension, even though I know I had at least two foot or more of clearance at belly button deep, without looking back to see that I wasn't getting any extra confidence.
Now, on the other hand, at around belly button deep I had no worries, just like I do with it chest mounted, but just the same if I were to go deeper than I knew I could with it chest mounted, I'd probably find myself constantly looking back to see what the deal is. So in other words, it works great confidence wise to belly button deep with no worries, but any deeper and I know I wouldn't feel any more confident even though the box is a good foot or so at least higher than chest mounted. Without it in your vision as you look down to confirm, at least for me I know my mind would be always having that doubt and making me to want to look back. Plano box here I come!
And the best part is, that at say top of the shoulder deep using the Plano box on an extension, it will still be out of the water not causing drag or floating issues, and since even top of the shoulder deep it will still be a tad out of the water, no worries of a potential leak with the box should it dip here and there. I feel that's the best route to take if you want to go upper chest or top of the shoulder deep, and IMO I wouldn't risk going much deeper than belly button deep without the Plano box, if anything just for the shear peace of mind it will bring.
Just the same, if I did take a spill I doubt water would get to the box inside the bag so long as I didn't take my good old time getting back up. But the Plano box will for sure make there be no worries at all as to getting the box wet when I get around to getting that to replace the bag. I just want to make sure that the rig works fine at just about shoulder deep before going further here, but I can't imagine what could possibly show up as a problem now with the first test run almost as deep as my waist in the strong waves yesterday.