Why does the Navy use a fouled anchor insignia?

An anchor that is foul of the cable or chain is a symbol found in various Navy crests.  No one really knows why the anchor was used as a symbol for the chief petty officer.

Many chiefs believe that it symbolizes the difficulty that they face everyday, but that is just a fanciful guess. The device is on the cap of the most naval officers, the distinguishing device of a Chief Petty Officer, the collar device of midshipman, and on the cap badges of the British naval officers.  

Many sailors regard the device a sign of poor seamanship.  Although, artistic to a civilian, it has been called a sailor's disgrace by some. 

The fouled anchor was first seen as an insignia of the Lord High Admiral of England, Lord Howard of Effignham, around 1588 during the Spanish Armada battle. More than 400 years later, the insignia is still the official seal for the admiral's office.

The fouled anchor insignia is just one example of how the British navy influenced the navies around the world.