Hi,
These naval expressions can be tricky.
Someone remarked that When a ship has been anchored, it doesn't move. It just stays there where it is. I wouldn't say that's necessarily true. The anchor line does not normally go straight down. There is some slack in it. Thus, the ship can move a little, eg forward or back, or in a circle around the anchor point. Consider the effects of wind and tide.
My dictionary offers these nautical definitions.
sheer: to swerve or change course
sheer: the upward slope of a ship's lines towards the bow and stern.
Where's GG? She was in the navy, I think.
Clive