Foul is a nautical term meaning to entangle or entwine, and more generally that something is wrong or difficult. The term dates back to usage with wind-driven sailing ships.

Fouled anchor

It is usually applied to the state of an anchor

Anchor

An anchor is a device, normally made of metal, that is used to connect a vessel to the bed of a body of water to prevent the vessel from drifting due to wind or current. The word derives from Latin ancora, which itself comes from the Greek ἄγκυρα .Anchors can either be temporary or permanent...

, which has become hooked on some impediment on the ground, or has its cable wound round the stock or flukes. The term is generally utilized when speaking of items of historical value such as the US Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 Chief Petty Officer

Chief Petty Officer

A chief petty officer is a senior non-commissioned officer in many navies and coast guards.-Canada:"Chief Petty Officer" refers to two ranks in the Canadian Navy...

 emblem. The fouled anchor is also the official seal of the Lord High Admiral

Admiralty

The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

 of Britain, presently HM Queen Elizabeth II

Elizabeth II of the United Kingdom

Elizabeth II is the constitutional monarch of 16 sovereign states known as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize,...

, and is flown on the ship carrying the monarch to sea. It is also flown during the launching of a warship of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

.

• Example: "It took me forever to untangle the anchor line. It was all fouled up!"

Other usage

The term can be applied to many nautical situations:

• Foul hawse - when a ship lying to two anchors gets the cables crossed.
• Foul bottom - in reference to a seafloor that has poor qualities for securing an anchor, such as hard rocks, coral, wreckage, or other impedents that would make securing or unsecuring an anchor difficult or impossible. Also, in reference to the hull of ship that is so encrusted with weeds and marine growth as to impede her progress.
• Foul wind - when a strong head wind prevents a sailing ship from keeping her desired course.
• Foul deck - on an aircraft carrier, when the deck is occupied by aircraft, thus preventing other aircraft from landing.