PANAMA CANAL REGULATIONS ON PANAMA CHOCKS

MR, January 1, 1998
MR Notice 10 Shipping No. N-1-98

8. Construction, Number and Location of Chocks and Bitts
  1. A vessel passing through the locks shall normally be assisted by electric towing locomotives using steel towing wires. At the discretion of the Manager, Transit Operations Division, certain vessels, usually those under 38.10 meters (125 feet) in length, may be handled with their own lines either against the lock wall or from both walls in the center of the chamber. Vessels transiting the Canal are required to have chocks and bitts as follows:
  1. All chocks for towing wires shall be of heavy closed construction and shall have a convex bearing surface with a radius of not less than 180 millimeters (7 inches). The convex surface shall extend so that a wire from the bitt, or from the towing locomotive through the chock, shall be tangent to the 180 millimeter (7 inches) radius at any angle up to 90 degrees with respect to a straight line through the chock.
  2. No part of the vessel which may be contracted by the towing wires, at any angle, shall have less than a 180 millimeter (7 inches) radius.
  3. Chocks designated as single chocks shall have a throat opening of not less than 650 square centimeters (100 square inches) in area – preferred dimensions are 350x230 millimeters (12 x 9 inches) – and shall be capable of withstanding a strain of 45,000 kilograms (100,000 pounds) on a towing wire from any direction.
  4. Chocks designated as double chocks shall have a throat opening of nor less than 900 square centimeters (140 square inches) in area – preferred dimensions are 355x255 millimeters (14 x 10 inches) – and shall be capable of withstanding a strain of 64,000 kilograms (140,000 pounds) on the towing wires from any direction.
  5. Use of existing roller chocks is permissible provided they are not less than 15 meters (49 feet) above the waterline at the vessel’s maximum Panama Canal draft and provided they are in good condition, meet all of the requirements for solid chocks as specified in paragraphs 8.a. (1), 8.a. (2), 8.a. (3) and 8.a. (4) of this section, as the case may be, and are so filled that transition from the rollers to the chock body will prevent damage to towing wires. Since January 1, 1994, roller chocks are not accepted in drawings of new constructions submitted for approval as per Par. 2.1 of this Notice.
  6. Each single chock shall have an accompanying bitt capable of withstanding a strain of 45,000 kilograms (100,000 pounds).
  7. Each double chock located at the stem and the stern, in accordance with paragraph 8.a. (8) of this section, shall have two pairs of accompanying heavy bitts with each bitt of each pair capable of withstanding a strain of 45,000 kilograms (100,000 pounds). Other double chocks shall have a pair of accompanying heavy bitts with each bitt capable of withstanding a strain of 45,000 kilograms (100,000 pounds)
  8. All vessels, except vessels not requiring locomotives, shall be fitted with a double chock set athwartships right in the stem and another double chock set athwartships right in the stern, except that on vessels of less than 22.86 meters (75 feet) beam, two single chocks may be substituted for each double chock required by this subsection; on vessels of over 22.86 meters (75 feet) beam two double chocks may be substituted. If such substitution is made, the chocks shall be placed port and starboard not more than 2.50 meters (8 feet) abaft the stem or 3 meters (10 feet) forward of the stern, provided that these chocks are not more than 3 meters (10 feet) from the center line of the vessel.
  9. Vessels under 60.96 meters (200 feet) in length and not exceeding 9.14 meters (30 feet) in beam shall have a double chock or two single chocks at the stem and stern. If the vessel is equipped with the two single chocks they shall be placed, port and starboard, not more than 2.50 meters (8 feet) abaft the stem or 3 meters (10 feet) forward of the stern, and not more than 3 meters (10 feet) off the center line (See figure 6).
  10. Vessels 60.96 to 121.92 meters (200 to 400 feet) in length and not exceeding 22.86 meters (75 feet) in beam shall have a double chock at the stem and at the stern or two single chocks at the bow and stern, port and starboard, not more than 2.50 meters (8 feet) abaft the stem or 3 meters (10 feet) forward of the stern and not more than 3 meters (10 feet) off the center line and shall have two additional single chocks, port and starboard, 9 to 16 meters (30 to 50 feet) abaft the stem and 9 to 16 meters (30 to 50 feet) forward of the stern (See figure 6).
  11. Vessels 121.92 to 173.74 meters (400 to 570 feet) long and not more than 22.86 meters (75 feet) in beam shall have a double chock at the stem and stern or two single chocks at the bow and stern port and starboard, and in addition shall have a double chock, port and starboard, 12 to 16 meters (40 to 50 feet) abaft the stem, a single chock, port and starboard, 12 to 16 meters (40 to 50 feet) forward of the stern (See figure 6).
  1. Vessels over 173.74 meters (570 feet) long or 22.86 meters (75 feet) in beam or over shall have a double chock at the stem and stern: a double chock, port and starboard, 12 tot 16 meters (40 to 50 feet) abaft the stem: 2 single chock, port and starboard, 24 to 28 meters (80 to 90 feet) abaft the stem: a double chock, port and starboard, 12 to 16 meters (40 to 50 feet) forward of the stern and a single chock, port and starboard, 24 to 28 meters (80 to 90 feet) forward of the stern.
  1. All vessels with a maximum beam of 27.74 meters (91 feet) or more, in addition to the double chock at the stern, which is required by 8.a. (12) above, shall have two single chocks on the stern. One chock shall be to port of the centerline and one chock shall be to starboard of the centerline. The single chocks shall be symmetrically spaced not less than 3 meters (10 feet) nor more than 5 meters (20 feet) from the centerline.
  2. Vessels with large flared bows or unusually high freeboard such as container vessels or vehicle carriers will be required to provide single closed chocks located further aft than those required in paragraph 8.a. (12) of this section for correct positioning of assisting tugs or may be required to fit recessed tug bollards into the hull, so that tugs can work without coming in contact with the bow flare or without requiring extra long lines and/or inefficient leads (See figure 6).
  3. Where recessed hull bitts are installed in the hull, they shall be installed not less than 3.7 meters (12 feet) nor more than 4.6 meters (15 feet) above the vessel’s waterline. Vessels which have an appreciable variation in draft, may be required to install recessed hull bitts are to be installed in the hull as far forward as possible, both port and starboard sides, where the bow flare does not exceed 25 degrees as measured from the vertical line of the vessels side. This position may require locating the chocks and bitts further aft than the 24 to 28 meters (80 to 90 feet) abaft the stem as in paragraph 8.a. (11) above. This position will allow PCC tugboats to work safely under the bow flare without the tugboats mast or pilothouse mast or pilothouse coming in contact with the vessel’s hull.
  4. A vessel not requiring locomotives shall have a chock arrangement similar to that described in paragraph 8.a. (9) of this section, except that the chocks need only be single chocks or, if approved by the Canal authorities, or lesser strength.
  5. Any vessel which fails to meet these requirements may be denied transit. If the Maritime Operations Director or his representative decides that the vessel can be handled without undue danger to equipment or to personnel, notwithstanding her failure to comply with other requirements of this section, the vessel may be allowed to transit after executing a release. The Master of the vessel must sign an undertaking for said vessel, her owners, operators, or any other persons having any interest in her, and for himself, releasing the Panama Canal Commission from and indemnifying it against, any loss, damage or liability incurred by the Panama Canal Commission to the extent and in the proportion that such failure to meet the requirements of this section proximately causes or contributes to the casually and resulting damages.
  6. All new building vessels are expected to comply with all current vessel requirements if placed in service after March 1. 1997. Pre-existing vessels are granted a waiver for one round trip or for one year from the date of the waiver, whichever comes first. Certain tank vessels, and other vessels which prove to the satisfaction of PCC that the work necessary to fit the chocks on the stern cannot be safely performed while at dockside, will be provided with a waiver extending until the next yard overhaul. Vessels with a PCC approved recessed bitt on the stern may, upon written application, be exempted from this requirement.