Unfortunately, after experimenting with many things, I cannot explain why all of kaha's wakes have lines in them. It doesn't happen on my system or many others so it very well may be some type of local problem due to the current installation of P3Dv4 on Kaha's system. But, that is just a guess. As kaha said, he will probably just have to wait until sometime in the future when he does a full reinstall of P3DvX.
Rod