---
kind: "section"
citation: "46 C.F.R. § 174.055"
title: "46"
number: "174.055"
heading: "Calculation of wind heeling moment (Hm)."
url: "https://uscodex.org/cfr/46/174.055"
---

# §174.055. Calculation of wind heeling moment (Hm).

- (a) The wind heeling moment (Hm) of a unit in a given normal operating condition or severe storm condition is the sum of the individual wind heeling moments (H) calculated for each of the exposed surfaces on the unit; i.e., Hm=Σ H.
- (b) Each wind heeling moment (H) must be calculated using the equation:
- (c) **When calculating “A” in the equation described in paragraph (b) of this section—**
  - (1) The projected area of each column or leg; if the unit has columns or legs, must not include shielding allowances;
  - (2) Each area exposed as a result of heel must be included;
  - (3) The projected area of a cluster of deck houses may be used instead of the projected area of each individual deck house in the cluster; and
  - (4) The projected area of open truss work may be calculated by taking 30% of the projected areas of both the front and back sides of the open truss work rather than by determining the projected area of each structural member of the truss work.

## Notes

### Amendments

[CGD 79-023, 48 FR 51048, Nov. 4, 1983, as amended by USCG-2014-0688, 79 FR 58287, Sept. 29, 2014]

### 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.

### Amendments

[CGD 79-023, 48 FR 51048, Nov. 4, 1983, as amended by USCG-2014-0688, 79 FR 58287, Sept. 29, 2014]