46 CFR 45.59: Definitions for superstructure corrections.

For the purpose of §§ 45.58 through 45.61—

(a) The standard height of a superstructure (Hs) other than a raised quarter deck and the standard height of a trunk (Hs) is determined by the formula:

Hs=[6.0 + (L/300)] ft

(b) The length of superstructure (S) is the length of those parts of the superstructure which extends to the sides of the vessel and that lie within the length (L).

(c) The effective length (E) of a trunk is its length in the ratio of its mean breadth to B.

(d) The effective length (E) of an enclosed superstructure of standard height or greater is its length “S”.

(e) Where the height of an enclosed superstructure or trunk is less than the standard height (Hs),the effective length (E) is its length reduced in the ratio of its height to Hs.

(f) The effective length (E) of a raised quarter deck of 2/3 Hs or greater that has no openings in the front bulkhead is its length up to a maximum of 0.6L.

(g) The effective length (E) of a raised quarter deck of less than 2/3 Hs or that does not have an intact front bulkhead is its length reduced by the ratio of its height to Hs.

Table 12(1)

tables of p values

Length of Ship (feet) Value of P

80 0.1100

90 0.1136

100 0.1172

110 0.1208

120 0.1244

130 0.1281

140 0.1318

150 0.1355

160 0.1393

170 0.1430

180 0.1468

190 0.1506

200 0.1545

210 0.1583

220 0.1622

230 0.1661

240 0.1700

250 0.1740

260 0.1780

270 0.1820

280 0.1860

290 0.1900

300 0.1941

310 0.1982

320 0.2023

330 0.2065

340 0.2106

350 0.2148

360 0.2190

370 0.2233

380 0.2275

390 0.2318

400 0.2361

410 0.2400

420 0.2437

430 0.2472

440 0.2506

450 0.2537

460 0.2567

470 0.2595

480 0.2621

490 0.2645

500 0.2667

510 0.2688

520 0.2706

530 0.2723

540 0.2738

550 0.2751

560 0.2762

570 0.2772

580 0.2779

590 0.2785

600 0.2788

610 0.2790

620 0.2790

630 0.2789

640 0.2785

650 0.2779

660 0.2772

670 0.2768

680 0.2760

690 0.2751

700 0.2740

710 0.2728

720 0.2715

730 0.2700

740 0.2684

750 0.2667

760 0.2648

770 0.2628

780 0.2607

790 0.2584

800 0.2560

810 0.2532

820 0.2504

830 0.2476

840 0.2448

850 0.2420

860 0.2392

870 0.2364

880 0.2336

890 0.2308

900 0.2280

910 0.2252

920 0.2224

930 0.2196

940 0.2168

950 0.2140

960 0.2112

970 0.2084

980 0.2056

990 0.2028

1000 0.2000

Table 12(2)

values of “a” for use in the expression

P1=P + “A” (L/D—L/Ds)

Length of Ship (feet) Value of “A”

80 0.00864

90 0.00806

100 0.00750

110 0.00696

120 0.00644

130 0.00594

140 0.00546

150 0.00500

160 0.00456

170 0.00414

180 0.00374

190 0.00336

200 0.00300

210 0.00266

220 0.00234

230 0.00204

240 0.00176

250 0.00150

260 0.00126

270 0.00104

280 0.00084

290 0.00066

300 0.00050

310 0.00036

320 0.00024

330 0.00014

340 0.00006

350 0.00000

Table 12(3)

values of l/ds

Length of Ship (feet) Value of L/D5

80 6.50000

90 6.76563

100 7.03125

110 7.29688

120 7.56250

130 7.82813

140 8.09375

150 8.35938

160 8.62500

170 8.89063

180 9.19625

190 9.42188

200 9.68750

210 9.95313

220 10.21875

230 10.48438

240 10.75000

250 11.01563

260 11.28125

270 11.54688

280 11.81250

290 12.07813

300 12.34375

310 12.60938

320 12.87500

330 13.14063

340 13.40625

350 13.67188

360 13.93750

370 14.20313

380 14.46875

390 14.73438

400 15.00000

(h) Superstructures which are not enclosed have no effective length.

(i) When a lower deck is designated as the freeboard deck, that part of the hull which extends above the freeboard deck is treated as a superstructure so far as concerns the application of the conditions of assignment and the calculation of freeboard.

(j) A bridge or poop is enclosed only when access is provided whereby the crew may reach accommodations, machinery, or other working spaces inside the superstructure by alternative means that are available at all times when bulkhead openings are closed.