I remember reading that when the navy needs to anchor over a fixed object , for say recovery/rescue of submarines etc. that they always do a three point anchoring thing where a smaller boat takes out an anchor out a "ways" (depending on how deep the water is) away from the main boat and sets an anchor, they more or less do this in three directions and they are able to stay stable over a spot no matter if he wind changes. I haven't tried it but I imagine it would keep shelters much more stable. In reading that some have this problem esp if higher winds come up. In an ice shelter you wouldn't have to have much line out from it because you are , unlike the boat, pulling from a high angle from the surface.
