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The provisions of this section apply to ship repairing, shipbuilding and shipbreaking.
Structural members | Light duty (Up to 25 pounds per square foot)-Height in feet | Heavy duty (25 to 75 pounds per square foot) Height in feet. | ||||
≤24 | 2>4≤40 | >40≤60 | ≤24 | 2>4≤40 | >40≤60 | |
Poles or uprights (in inches) | 2x4 | 3x4 or 2x6 | 4x4 | 3x4 | 4x4 | 4x6 |
Bearers (in inches) | 2x6 | 2x6 | 2x6 | 2x8 | 2x8 | 2x10 |
Ledgers (in inches) | 2x6 | 2x6 | 2x6 | 2x8 | 2x8 | 2x8 |
Stringers (not supporting bearers) (in inches) | 1x6 | 1x6 | 1x6 | 1x6 | 1x6 | 1x6 |
Braces (in inches) | 1x4 | 1x6 | 1x6 | 1x6 | 1x6 | 1x6 |
Pole spacing-longitudinally (in feet) | 7½ | 7½ | 7½ | 7 | 7 | 7 |
Pole spacing-transversely (in feet) | 6½ min | 7½ min | 8½ min | 6½ min | 10 | 10 |
Ledger spacing-vertically (in feet) | 7 | 7 | 7 | 4 ½ | 4 ½ | 4 ½ |
Length (in feet) | Cross section (in inches) | |
At ends | At center | |
15 | 1 7/8 × 2 3/4 | 1 7/8 × 3 3/4 |
16 | 1 7/8 × 2 3/4 | 1 7/8 × 3 3/4 |
18 | 1 7/8 × 3 | 1 7/8 × 4 |
20 | 1 7/8 × 3 | 1 7/8 × 4 |
24 | 1 7/8 × 3 | 1 7/8 × 4 1/2 |
Structural members | Height in feet | ||
≤10 | >10≤16 | 16≤20 | |
Inches | inches | inches | |
Legs | 2 x 4 | 3 x 4 | 4 x 6 |
Bearers or headers | 2 x 6 | 2 x 8 | 4 x 6 |
Crossbraces | 2 x 4 | 2 x 4 | 2 x 6 |
Or | |||
1 x 8 | |||
Longitudinal braces | 2 x 4 | 2 x 6 | 2 x 6 |
Span in feet | Lumber dimensions in inches | |||||||||
A | B | A | B | A | B | A | B | A | B | |
2x10 | 1 5/8 x 9 ½ | 2x12 | 1 5/8x11 1/2 | 3x8 | 2 5/8x 7 /12 | 3x10 | 2 5/8x 9 ½ | 3x12 | 2 5/8x 11 ½ | |
6 | 256 | 309 | 526 | 667 | 807 | |||||
8 | 192 | 232 | 395 | 500 | 605 | |||||
10 | 153 | 186 | 316 | 400 | 484 | |||||
12 | 128 | 155 | 263 | 333 | 404 | |||||
14 | 110 | 133 | 225 | 286 | 346 | |||||
16 | 116 | 197 | 250 | 303 | ||||||
Footnote(A) Rough lumber. Footnote(B) Dressed lumber. |
Improved plow steel, rope diameter, inches | Number of clips | Minimum spacing, inches | |
Drop forged | Other Material | ||
(1) | |||
1/2 | 3 | 4 | 3 |
5/8 | 3 | 4 | 3 3/4 |
3/4 | 4 | 5 | 4 1/2 |
7/8 | 4 | 5 | 5 1/4 |
1 | 4 | 6 | 6 |
1 1/8 | 5 | 6 | 6 3/4 |
1 1/4 | 5 | 7 | 7 1/2 |
1 3/8 | 6 | 7 | 8 1/4 |
1 1/2 | 6 | 8 | 9 |
Footnote(1) Three clips shall be used on wire size less than ½- inch diameter. |
Chain size in inches | Maximum allowable wear in fractions of inches |
1/4 (9/32) | 3/64 |
3/8 | 5/64 |
1/2 | 7/64 |
5/8 | 9/64 |
3/4 | 5/32 |
7/8 | 11/64 |
1 | 3/16 |
1 1/8 | 7/32 |
1 1/4 | 1/4 |
1 3/8 | 9/32 |
1 1/2 | 5/16 |
1 3/4 | 11/32 |
[67 FR 44542 July 3, 2002; 76 FR 33610 June 8, 2011]