#### § 42.20-60 Deduction for superstructures and trunks.

(a) Where the effective length of superstructures and trunks is 1.0*L,* the deduction from the freeboard shall be 14 inches at 79 feet length of vessel, 34 inches at 279 feet length, and 42 inches at 400 feet length and above; deductions at intermediate lengths shall be obtained by linear interpolation.

(b) Where the total effective length of superstructures and trunks is less than 1.0*L* the deduction shall be a percentage obtained from table [42.20-60(b)(1)](/on/2024-09-23/title-46/section-42.20-60#p-42.20-60(b)(1)) or table [42.20-60(b)(2)](/on/2024-09-23/title-46/section-42.20-60#p-42.20-60(b)(2)):

Table [42.20-60](/on/2024-09-23/title-46/section-42.20-60)(b)(1)—Percentage of Deduction For Type “A” Vessels

| | Total effective length of superstructures and trunks | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 0 | 0.1*L* | 0.2*L* | 0.3*L* | 0.4*L* | 0.5*L* | 0.6*L* | 0.7*L* | 0.8*L* | 0.9*L* | 1.0*L* |
| Percentage of deduction for all types of superstructures1 | 0 | 7 | 14 | 21 | 31 | 41 | 52 | 63 | 75.3 | 87.7 | 100 |
| | | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 Percentages at intermediate lengths of superstructures and trunks shall be obtained by linear interpolation. | | | | | | | | | | | |

Table [42.20-60](/on/2024-09-23/title-46/section-42.20-60)(b)(2)—Percentage of Deduction for Type “B” Vessels

[*Percentage of deduction*1]

| | Total effective length of superstructures and trunks | | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Line | 0 | 0.1*L* | 0.2*L* | 0.3*L* | 0.4*L* | 0.5*L* | 0.6*L* | 0.7*L* | 0.8*L* | 0.9*L* | 1.0*L* |
| Vessels with forecastle and without detached bridge | I | 0 | 5 | 10 | 15 | 23.5 | 32 | 46 | 63 | 75.3 | 87.7 | 100 |
| Vessels with forecastle and detached bridge | II | 0 | 6.3 | 12.7 | 19 | 27.5 | 36 | 46 | 63 | 75.3 | 87.7 | 100 |
| | | | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 Percentages at intermediate lengths of superstructures and trunks shall be obtained by linear interpolation. | | | | | | | | | | | | |

(c) For vessels of Type “B”:

(1) Where the effective length of a bridge is less than 0.2*L,* the percentages shall be obtained by linear interpolation between lines I and II;

(2) Where the effective length of a forecastle is more than 0.4*L,* the percentages shall be obtained from line II; and,

(3) Where the effective length of a forecastle is less than 0.07*L,* the percentages in table [42.20-60(b)(2)](/on/2024-09-23/title-46/section-42.20-60#p-42.20-60(b)(2)) of this paragraph shall be reduced by:

5(0.07*L*−*f*)/0.07*L*

*L* is the length of vessel as defined in [§ 42.13-15(a)](/on/2024-09-23/title-46/section-42.13-15#p-42.13-15(a)),

*f* is the effective length of the forecastle.

[CGFR 68-60, [33 FR 10065](https://www.federalregister.gov/citation/33-FR-10065), July 12, 1968, as amended by CGFR 68-126, [34 FR 9015](https://www.federalregister.gov/citation/34-FR-9015), June 5, 1969; USCG-2014-0688, [79 FR 58280](https://www.federalregister.gov/citation/79-FR-58280), Sept. 29, 2014]