The phrase 'lay at anchor' is not possible to find in any standard dictionary but it is the common knowledge that every language evolves itself and the same happens with English. The language is evolving and it may be possible that in near future the phrase will become the part of the Standard English dictionary.
The word anchor is used to convey the idea of a heavy metal object that sailors used to keep their ship at one particular place when they are in water. The object is connected with a rope and it helps the ship to be at one place.
The possible meaning that you can figure out from the use of the phrase is that of keeping a vehicle or ship at one place and even if it is required, the vehicle is not moving as it feared to tread a difficult path.
The word anchor is used to convey the idea of a heavy metal object that sailors used to keep their ship at one particular place when they are in water. The object is connected with a rope and it helps the ship to be at one place.
The possible meaning that you can figure out from the use of the phrase is that of keeping a vehicle or ship at one place and even if it is required, the vehicle is not moving as it feared to tread a difficult path.