All right, here they are. I've only noticed this on the type VIIC u-flak while using GWX. These are the "floats" and attachment points on the guide wires of the VIIC. They are in the right spot--just off set to the left of the u-boat. Further, the floats are on and in the right spot on the u-boat as well. These are present with the default GWX and all other skins I have. Invisible boat following me around?
Here is a better view of the floats in front.
Again, note that they are aligned with the floats and attachment points on the u-boat.
I hope that helps.
J