Mark, I've read you posting about this issue before. I have to confess I dropped out of O level Physics, I simply couldn't understand the Master who taught it, though I dearly wanted to. It must have been my fault, enough others went on to get a pass in the exam.
I have made identical bodied floats, with just different antennae, and they have behaved differently to one another. Those with tips of a more bouyant material sitting higher in the water and taking more shot to sink that antenna.
Those with antennae of a less bouyant material, such as a cocktail stick or whittled-down cane, have required less shot to sit right in the water and have concealed more of the tip section for less shot.
I can follow that the different materials have done no more than alter the centre of bouyancy, but how can it be that the tips behave so differently?
I'm currently fishing Duckers of either cork with balsa fairings top and bottom, or balsa, both on a cane stem and I have found that even when the fish are simply just not in the mood I can allow as much as two inches of cane to show and still get bites, as the fish swim away with the bait and eventually decide to swallow it, not having detected the float.
Others fishing near me with, for example, a loaded waggler with a bouyant insert tip cannot get a bite to strike to. The float goes under but the bait is immediately rejected, presumably as the fish move on without closing their mouths or simply that they detect the resistance to going under of the more bouyant float.
In the past, when I fished whips and poles more, I found I could still get fish in the net when they were like this by having very slim bodied floats shotted until they sank thier tips below the surface with the weight of the bait. If the fish took the bait out to deeper water ( and those ruddy crucians did every time) and then dropped it , it still sank to the bottom and they then accepted it.
Of course, I could be wrong. Many thought I was mad. Perhaps a gudgeon was sneaking off with the bait and then a crucian was bullying it off them.
I don't really know what was happening, just the thought processes that led me there.I can say, hand on heart, that for a whole Summer I took fish on a daily basis whilst others went home without a catch. Nobodys luck holds out that long..surely it had to be these barely bouyant rigs I was fishing with?
I simply try to create the same situation with running line floats that I had with pole floats.