---
kind: "section"
citation: "46 C.F.R. § 174.320"
title: "46"
number: "174.320"
heading: "Damage survival."
url: "https://uscodex.org/cfr/46/174.320"
---

# §174.320. Damage survival.


A hopper dredge survives assumed damage if it meets the following conditions:

- (a) The maximum angle of heel in each stage of flooding must not exceed 30 degrees or the angle of downflooding whichever is less.
- (b) The final waterline, taking into account sinkage, heel, and trim, must be below the lowest edge of each opening through which progressive flooding may take place.
- (c) **The righting arm curve calculated after damage must—**
  - (1) Have a minimum positive range of 20 degrees beyond the angle of equilibrium; and
  - (2) **Reach a height of at least 4 inches (l00mm) within the 20 degree positive range.**
- (d) Each opening within, or partially within, the 20 degree range beyond the angle of equilibrium must be weathertight.
- (e) After flooding or equalization as allowed by [§ 174.325](/cfr/46/174.325.md), the hopper dredge's metacentric height must be at least 2 inches (50mm) when the dredge is in an upright position.

## Notes

### Source

Source: CGD 76-080, 54 FR 36977, Sept. 6, 1989, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 9118, 9119, 9153; 43 U.S.C. 1333; 46 U.S.C. 3306, 3703; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department of Homeland Security Delegation No. 0170.1. Section 174.180 also issued under sec. 617, Pub. L. 111-281, 124 Stat. 2905.

### Source

Source: CGD 79-023, 48 FR 51048, Nov. 4, 1983, unless otherwise noted.