The master of any vessel from a foreign port or place, or of a hovering vessel which has received or delivered merchandise while outside the territorial sea, who allows any merchandise (including sea stores) to be unladen from such vessel at any time after its arrival within the customs waters and before such vessel has come to the proper place for the discharge of such merchandise, and before he has received a permit to unlade, shall be liable to a penalty equal to twice the value of the merchandise but not less than $10,000, and such vessel and its cargo and the merchandise so unladen shall be seized and forfeited.

The master of any vessel from a foreign port or place, or of a hovering vessel which has received or delivered merchandise while outside the territorial sea, who allows any merchandise (including sea stores), the importation of which into the United States is prohibited, or which consists of any spirits, wines, or other alcoholic liquors, to be unladen from his vessel at any place upon the high seas adjacent to the customs waters of the United States to be transshipped to or placed in or received on any vessel of any description, with knowledge, or under circumstances indicating the purpose to render it possible, that such merchandise, or any part thereof, may be introduced, or attempted to be introduced, into the United States in violation of law, shall be liable to a penalty equal to twice the value of the merchandise but not less than $10,000, and the vessel from which the merchandise is so unladen, and its cargo and such merchandise, shall be seized and forfeited.

The master of any vessel from a foreign port or place, or of a hovering vessel which has received or delivered merchandise while outside the territorial sea, who allows any merchandise (including sea stores) destined to the United States, the importation of which into the United States is prohibited, or which consists of any spirits, wines, or other alcoholic liquors, to be unladen, without permit to unlade, at any place upon the high seas adjacent to the customs waters of the United States, to be transshipped to or placed in or received on any vessel of the United States or any other vessel which is owned by any person a citizen of, or domiciled in, the United States, or any corporation incorporated in the United States, shall be liable to a penalty equal to twice the value of the merchandise but not less than $10,000, and the vessel from which the merchandise is so unladen, and its cargo and such merchandise, shall be seized and forfeited.

If any merchandise (including sea stores) unladen in violation of the provisions of this section is transshipped to or placed in or received on any other vessel, the master of the vessel on which such merchandise is placed, and any person aiding or assisting therein, shall be liable to a penalty equal to twice the value of the merchandise, but not less than $10,000, and such vessel, and its cargo and such merchandise, shall be seized and forfeited.

Whoever, at any place, if a citizen of the United States, or at any place in the United States or within customs waters, if a foreign national, shall engage or aid or assist in any unlading or transshipment of any merchandise in consequence of which any vessel becomes subject to forfeiture under the provisions of this section shall, in addition to any other penalties provided by law, be liable to imprisonment for not more than 15 years.

Whenever any part of the cargo or stores of a vessel has been unladen or transshipped because of accident, stress of weather, or other necessity, the master of such vessel and the master of any vessel to which such cargo or stores has been transshipped shall, as soon as possible thereafter, notify the Customs Service at the district within which such unlading or transshipment has occurred, or the Customs Service at the district at which such vessel shall first arrive thereafter, and shall furnish proof that such unlading or transshipment was made necessary by accident, stress of weather, or other unavoidable cause, and if the Customs Service is satisfied that the unlading or transshipment was in fact due to accident, stress of weather, or other necessity, the penalties described in this section shall not be incurred.