33 C.F.R. § 165.501
(a) Location. The waters enclosed by the shoreline and the following lines are a Regulated Navigation Area:
(2) Inland zone. The waters enclosed by the shoreline and the following lines:
(b) Definitions. In this section:
CBBT means the Chesapeake Bay Bridge Tunnel.
Coast Guard Patrol Commander is a Coast Guard commissioned, warrant or petty officer who has been designated by the Commander, Coast Guard Sector Virginia.
Designated representative of the Captain of the Port means a person, including the command duty officer at Coast Guard Sector Virginia or the Coast Guard or Navy Patrol Commander who has been authorized by the Captain of the Port to act on his or her behalf and at his or her request to carry out such orders and directions as needed. All patrol vessels shall display the Coast Guard Ensign at all times when underway.
I-664 Bridge Tunnel means the Monitor Merrimac Bridge Tunnel.
Inland waters means waters within the COLREGS Line of Demarcation.
Thimble Shoal Channel consists of the waters bounded by a line connecting Thimble Shoal Channel Lighted Bell Buoy 1TS, thence to Thimble Shoal Lighted Gong Buoy 17, thence to Thimble Shoal Lighted Buoy 19, thence to Thimble Shoal Lighted Buoy 21, thence to Thimble Shoal Lighted Buoy 22, thence to Thimble Shoal Lighted Buoy 18, thence to Thimble Shoal Lighted Buoy 2, thence to the beginning.
Thimble Shoal North Auxiliary Channel consists of the waters in a rectangular area 450 feet wide adjacent to the north side of Thimble Shoal Channel, the southern boundary of which extends from Thimble Shoal Channel Lighted Buoy 2 to Thimble Shoal Lighted Buoy 18.
Thimble Shoal South Auxiliary Channel consists of the waters in a rectangular area 450 feet wide adjacent to the south side of Thimble Shoal Channel, the northern boundary of which extends from Thimble Shoal Channel Lighted Bell Buoy 1TS, thence to Thimble Shoal Lighted Gong Buoy 17, thence to Thimble Shoal Lighted Buoy 19, thence to Thimble Shoal Lighted Buoy 21.
(c) Applicability. This section applies to all vessels operating within the Regulated Navigation Area, including naval and public vessels, except vessels that are engaged in the following operations:
(d) Regulations.
(1) Anchoring restrictions. No vessel over 65 feet long may anchor or moor in the inland waters of the Regulated Navigation Area outside an anchorage designated in § 110.168 of this title, with these exceptions:
(3) Secondary towing rig requirements on inland waters.
(i) A vessel over 100 gross tons may not be towed in the inland waters of the Regulated Navigation Area unless it is equipped with a secondary towing rig, in addition to its primary towing rig, that:
(ii) A tow consisting of two or more vessels, each of which is less than 100 gross tons, that has a total gross tonnage that is over 100 gross tons, shall be equipped with a secondary towing rig between each vessel in the tow, in addition to its primary towing rigs, while the tow is operating within this Regulated Navigation Area. The secondary towing rig must:
(4) Thimble Shoals Channel controls.
(6) Requirements for navigation charts, radars, and pilots. No vessel over 100 gross tons may enter the Regulated Navigation Area, unless it has on board:
(7) Emergency procedures.
(9) Port security requirements. This paragraph shall only apply when the Commandant or the Captain of the Port sets MARSEC Level 2 or 3, as detailed in 33 CFR part 101, for any area, operation, or industry within the Regulated Navigation Area. Vessels in excess of 300 gross tons, including tug and barge combinations in excess of 300 gross tons (combined), shall not enter the Regulated Navigation Area, move within the Regulated Navigation Area, or be present within the Regulated Navigation Area, unless they comply with the following requirements:
(e) Waivers.
(f) Control of vessels within the regulated navigation area.
[USCG-2023-0059, 88 FR 32970, May 23, 2023]