33 CFR § 84.01 - Definitions.

---
identifier: "/us/cfr/t33/s84.01"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "33 CFR § 84.01 - Definitions."
title_number: 33
title_name: "Navigation and Navigable Waters"
section_number: "84.01"
section_name: "Definitions."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "E"
subchapter_name: "INLAND NAVIGATION RULES"
part_number: "84"
part_name: "ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Sec. 303, Pub. L. 108-293, 118 Stat. 1042 (33 U.S.C. 2071); Department of Homeland Security Delegation No. 0170.1."
regulatory_source: "79 FR 37921, July 2, 2014, unless otherwise noted."
cfr_part: "84"
---


# 84.01 Definitions.

(a) The term *height above the hull* means height above the uppermost continuous deck. This height shall be measured from the position vertically beneath the location of the light.

(b) *High-speed craft* means a craft capable of maximum speed in meters per second (m/s) equal to or exceeding: 3.7▽
<sup>0.1667</sup>; where ▽ = displacement corresponding to the design waterline (cubic meters).

The same formula expressed in pounds and knots is maximum speed in knots (kts) equal to exceeding 1.98 (lbs) 3.7▽
<sup>0.1667</sup>; where ▽ = displacement corresponding to design waterline in pounds.

(c) The term *practical cut-off* means, for vessels 20 meters or more in length, 12.5 percent of the minimum luminous intensity (Table 84.14(b)) corresponding to the greatest range of visibility for which the requirements of Annex I (33 CFR part 84) are met.

(d) The term *Rule* or *Rules* has the same meaning as in 33 CFR 83.03(r).