Why do they have a tangled anchor on your licence?

I would think that most USMM masters could do better.

Capt Joe
USMM Master

As an amulet, the fouled anchor is carried to ensure safe travel.

Another amuletic use for the fouled anchor is found in the
African-American hoodoo tradition. Here, as an extension of the
symbol's use as a safe travel charm, it implies safe return to the
home, and thus faithfulness and marital fidelity.

For jar heads It consisted of the world globe revealing the western
hemisphere because the British Royal Marines also had a globe but
depicting the eastern hemisphere, their origin. Atop the globe sat an
eagle with its wings outstretched. After often-bitter debate they
settled on the crested eagle as opposed to the bald eagle. The bald
eagle was found only in North America whereas the crested eagle was
found throughout the world. This symbol reflects the Corps' worldwide
mission. The anchor fostered even more debate as every Marine realized
that the Corps was a land arm of the Navy it had not always been. After
the War of 1812, the Corps briefly operated under the Army. The Corps
wanted to show its attachment to the Navy but also to reflect that they
were not sailors, but Marines. Interestingly the idea of a fouled
anchor came from the Navy who also used an anchor as its emblem. A
sailor would never foul (letting the line inappropriately wrap around
the anchor) an anchor. So the Corps adopted the fouled anchor to
tacitly say, "We are Navy but not sailors, we are Marines".

For the coasties the trade mark of the Coast Guard Chief Petty Officer,
"The Anchor," was inherited from the Revenue Cutter Service. The fouled
anchor with a shield superimposed to its shank (the emblem of the
Officers of the Revenue Cutter Service) is still worn on the shoulder
boards of Coast Guard Flag Officers.

The anchor is the identifying authority of the Chief Petty Officer and
is emblematic of a Chief. It represents stability and security. It
reminds Chiefs of their responsibility to keep those they serve safe
from harm's way.

For the Navy FOULED ANCHOR - The foul anchor as a naval insignia got
its start as the seal of the Lord Howard of Effingham. He was the Lord
Admiral of England at the time of the defeat of the Spanish Armada in
1588. During this period the personal seal of a great officer of state
was adopted as the seal of his office. The fouled anchor still remains
the official seal of the Lord High Admiral of Great Britain. When this
office became part of the present Board of Admiralty, the seal was
retained on buttons, official seals, and cap badges. The Navy's
adoption of this symbol and many other customs can be directly
attributed to the influence of British Naval tradition. The fouled
anchor is among them.

For the Merchant Marines Officers licensed by the Bureau of Marine
Inspection and Navigation or the Merchant Marine Inspection Service of
the Coast Guard wear fouled anchor inside wreath.

Joe