33 CFR § 147.843 - Thunder Horse Semi-Submersible safety zone.

---
identifier: "/us/cfr/t33/s147.843"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "33 CFR § 147.843 - Thunder Horse Semi-Submersible safety zone."
title_number: 33
title_name: "Navigation and Navigable Waters"
section_number: "147.843"
section_name: "Thunder Horse Semi-Submersible safety zone."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "N"
subchapter_name: "OUTER CONTINENTAL SHELF ACTIVITIES"
part_number: "147"
part_name: "SAFETY ZONES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "14 U.S.C. 544; 43 U.S.C. 1333; 33 CFR 1.05-1; Department of Homeland Security Delegation No. 00170.1, Revision No. 01.4."
regulatory_source: "CGD 78-160, 47 FR 9386, Mar. 4, 1982, unless otherwise noted."
cfr_part: "147"
---


# 147.843 Thunder Horse Semi-Submersible safety zone.

(a) *Description.* Thunder Horse Semi-Submersible, Mississippi Canyon 778 (MC 778), located at position 28°11′26″ N, 88°29′44″ W. The area within 500 meters (1640.4 feet) from each point on the structure's outer edge is a safety zone. These coordinates are based upon [NAD 83].

(b) *Regulation.* No vessel may enter or remain in this safety zone except the following:

(1) An attending vessel;

(2) A vessel under 100 feet in length overall not engaged in towing; or

(3) A vessel authorized by the Commander, USCG Heartland District.

[CGD08-05-019, 70 FR 43770, July 29, 2005]