---
kind: "section"
citation: "46 C.F.R. § 170.290"
title: "46"
number: "170.290"
heading: "Free surface correction for damage stability calculations."
url: "https://uscodex.org/cfr/46/170.290"
---

# §170.290. Free surface correction for damage stability calculations.

- (a) When doing the damage stability calculations required by this subchapter, the virtual increase in the vessel's vertical center of gravity due to liquids in tanks must be determined by calculating—
  - (1) For each type of consumable liquid, the free surface effect of at least one transverse pair of wing tanks or a single centerline tank; and
  - (2) **The free surface effect of each partially filled tank containing other than consumable liquids.**
- (b) For the purpose of [paragraph (a)(1)](#a-1) of this section, the tank or combination of tanks selected must be those having the greatest free surface effect.
- (c) When doing the calculations in [paragraph (a)](#a) of this section, the free surface effect of a liquid in a tank must be determined by—
  - (1) Assuming the vessel is heeled five degrees from the vertical; or
  - (2) Calculating the shift of the center of gravity of the liquid in the tank by the moment of transference method.

## Notes

### Authority

Authority: 43 U.S.C. 1333; 46 U.S.C. 2103, 3306, 3703; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department of Homeland Security Delegation No. 0170.1.

### Source

Source: CGD 79-023, 48 FR 51010, Nov. 4, 1983, unless otherwise noted.