Mr. X said:I often use my 11 litre RA float in very dense weed (esp. when the tide is low) & have not had any problems with it -- perhaps because it is hard, shiney & stream-line (no rings, straps, etc.). It has balast but sits quite high in the water. Moving steadily seems to be key -- give the weed the opportunity to move with you. The float line tangling with itself is more of an issue (not a biggie though) -- thicker lines, like the foam filled RA floatline, would prob. tangle less.
It sounds like we are still not quite on the same page. Could you pull your 11 liter float under water with you on a dive? If not, it wouldn't work in our kelp. We dive, go under a lot of kelp with stalks at thick as your wrist, and then come up on the other side. The float line follows us, so we would have to pull that float down to maybe 50 feet or whatever depth we dove, drag it under all those kelp stalks, and then up on the other side.
Even if the float had no buoyancy at all, it would be hanging up on the kelp, but the buoyancy makes it a nightmare. Next time you are diving, grab your float line about 5 feet below the float and try to dive with it behind you. If you succeed in getting it very far under water, then imagine some horizontal steel cables and think about swimming under them with the float behind you. Then you will see why floats won't work diving in our kelp.