AMC-581-1A-Inspection and Preservation of Ground Tackle (4 sheets).pdf

AMC-581-1A

SEPTEMBER 1992

SUPERSEDING

AMC-581-1

MARCH 1988

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA)

ATLANTIC MARINE CENTER

STANDARD SPECIFICATION AMC-581-1A

INSPECTION AND PRESERVATION OF GROUND TACKLE

1. SCOPE. This specification contains the requirements for inspection, preservation, and marking of anchors and anchor chain.

2. REFERENCES.

a. Steel Structures Painting Council Surface Preparation Specification No. 10 (SSPC-SP 10-85), "Near White Blast Cleaning"

3. REQUIREMENTS.

3.1 Removal. Remove anchors and anchor chain, including

shackles, shackle pins, and detachable links, from the ship and fake the chain onto the dock. Disassemble all detachable links and shackles.

3.2 Preparation. Sandblast the chains, anchors, detachable

links, shackles, swivels, and other fittings to a near white metal in accordance with reference 2.a. and apply one coat, 2.0-

3.0 mils dry film thickness, epoxy-polymide, MIL-P-24441A, Formula 150 (green).

3.3 Tests and Inspections. After sandblasting and applying one coat of paint, conduct the following:

3.3.1 Visual Inspections. Conduct a visual inspection of

all anchors, anchor chains, detachable links, shackles, shackle pins, swivels, locking pins, and other fittings for excessive wear, corrosion, distortion, cracks, and other defects.

3.3.2 Wire Diameter Inspections. Conduct inspections of

each anchor chain link to determine the mean diameter as follows:

a. Take two wire diameter measurements at each end of each link at the bearing area. The two measurements shall be at right angles to each other. A snap gage may be used to take the measurements. If the snap gage will not fit over the link in two places at right angles to each other, the link is acceptable. If the snap gage fits over the link during either measurement, the actual dimensions shall be taken using a micrometer.

b. When micrometer measurements are taken, calculate the mean diameter by averaging the two micrometer readings taken of the link. Compare the calculated mean wire diameter to the table in paragraph 3.3.4.

c. Record the mean wire diameter, and mark the links, which are less than or equal to the 90-percent nominal wire diameter listed. Prior to proceeding with any preservation of the chain, submit to the COTR a report of all links which failed this acceptance criteria.

3.3.3 Six-Link Dimensional Inspection.

a. With a load applied to the chain equal to 10 percent of the proof load, perform a six-link dimensional inspection, measured from every third link, of the entire chain.

The table in paragraph 3.3.4 provides the 10-percent proof load and the maximum six-link dimension for standard anchor chain sizes.

b. A bar gage shall be used to check the six-link dimension. When the bar gage will not fit over the ends of the links, the chain has been stretched and is not suitable for further use. Mark all chain sections which have been stretched beyond that specified. Prior to proceeding with any preservation of the chain, submit to the COTR a report of the sections which failed the acceptance criteria.

3.3.4 Anchor Chain Table.

Chain Size 90 Percent Six-Link 10-Percent Nom. Wire Dia. Nom. Wire Dia. Dimension Proof Load (Inches) (Inches) (Inches) (Pounds)

3/4 0.675 20-1/16 4,800 7/8 0.788 23-13/32 6,400 1 0.900 26-3/4 8,400 1-1/16 0.956 28-7/16 9,400 1-1/8 1.013 30-3/32 10,600 1-3/16 1.069 31-49/64 11,700 1-1/4 1.125 33-7/16 13,000 1-3/8 1.238 36-25/32 15,700 1-7/16 1.294 38-15/32 17,000 1-1/2 1.350 40-1/8 18,500 1-9/16 1.406 41-13/16 20,000 1-5/8 1.463 43-15/32 21,600 1-11/16 1.519 45-1/16 23,200 1-3/4 1.575 46-13/16 24,900 1-13/16 1.631 48-31/64 26,700 1-7/8 1.688 50-5/32 28,500 2 1.800 53-1/2 32,200

3.3.5 In the event the chain is a size not listed in the

above table, the COTR shall provide the required information.

3.4 Reassembly. After all tests and inspections, reassemble

the chain shots, detachable links, swivels, and other fittings.

Renew all locking wire with new stainless steel 304 wire. Pack detachable links during reassembly with molybdenum disulfide grease. During reassembly, the COTR may direct shots of chain be arranged in different order and locations than when disassembled.

The COTR may also elect to provide new shots of chain to be used in lieu of existing shots.

3.5 Preservation. After completion of inspections, continue

with preservation of the chains, anchors, detachable links, shackles, swivels, and other fittings by applying the following coating system:

3.5.1 One coat, 2.0-3.0 mils dry film thickness, epoxy-

polymide, MIL-P-24441A, Formula 150 (green). This coat is in addition to the coat applied prior to inspections.

3.5.2 One coat, 2.0-3.0 mils dry film thickness, epoxy-

polymide, MIL-P-24441A, Formula 153 (black).

3.5.3 To the anchor only, apply one coat, 2.0-3.0 mils dry

film thickness, black silicone alkyd marine grade paint while the last coat of epoxy-polymide is still tacky.

3.6 Markings.

3.6.1 Mark each shot of chain with turns of wire on the

studs of certain links as follows:

a. Locate the detachable link between the first and the second 15-fathom shots from the anchor. Mark the first link on each side (total of 2 links) of this detachable link with one turn of wire on the studs of the links.

b. Locate the detachable link between the second and third 15-fathom shots from the anchor. Mark the second link on each side (total of 2 links) of this detachable link with two turns of wire on the studs of the links.

c. Continue to mark all the chain in the same manner, each time counting an additional link from the detachable link in each direction and marking each of the two links with one more turn of wire than the preceding two links.

d. The anchor chains on each side of the ship shall be marked in the same manner.

e. In the event no detachable links are installed, a similar marking system shall be used to mark the chain at 15-fathom locations.

3.6.2 Using 2.0-3.0 mils dry film thickness of silicone

alkyd marine grade paint, mark the anchor chains as follows:

a. Paint red all detachable links. T

b. Paint white one link on each side (total of two) * of the detachable link between the first and second 15-fathom * shots from the anchor. *

c. Paint white two links on each side (total of four) * of the detachable link between the second and third 15-fathom * shots from the anchor. *

d. Paint white three links on each side (total of * six) of the detachable link between the third and fourth 15- * fathom shots from the anchor. *

e. Continue the sequence of painting white the links * on each side of the detachable links, increasing by one link on * each side of each successive detachable link, until the entire * length of chain (excluding the last two inboard shots on each * side) has been marked. *

f. In lieu of marking the last two inboard links as * specified above, paint red all links in the last inboard 15- * fathom shot and paint yellow all links in the next-to-last * inboard 15-fathom shot. R

g. The chains shall be painted the same on each side of the ship.

h. In the event the chains do not have detachable links, they shall be painted in a similar manner at 15-fathom locations.

3.7 Reinstallation. After completion of all other work, reinstall the anchors and chains on the ship, connected and stowed in their normal place.

END OF SPECIFICATION