An anchor line is an essential part of a boat's anchoring system. It provides the connection between the anchor and the boat, keeping the boat in place even in strong currents or winds. A lead anchor line is weighted with a lead weight at the end, which helps the anchor to sit better on the bottom and increases the stability of the boat.

Polyester 3-strand and 16-strand anchor lines are different types of ropes used as anchor lines. A polyester 3-strand anchor line consists of three twisted strands of polyester fibers and is generally flexible and easy to handle. A 16-strand anchor line has more strands, making it stronger and more durable, but it can also be stiffer and less flexible than a 3-strand line.

The difference in length between anchor lines can be determined by several factors, including the size of the boat, the depth of the water in which you are anchoring, and the expected conditions (such as wind and current). It is important to choose an anchor line that is long enough to allow the boat to move freely and to prevent the anchor from accidentally becoming dislodged.