Subpart E-Special Rules Pertaining

to Tugboats and Towboats

§ 174.140 Specific applicability.

Each tugboat and towboat inspected under Subchapter I of this chapter must comply with this subpart.

§ 174.145 Intact stability requirements.

(a) In each condition of loading and operation, each vessel must be shown by design calculations to meet the re#quirements of paragraphs (b) through (e) of this section.

(b) The area under each righting arm curve must be at least 16.9 footdegrees (5.15 meter-degrees) up to the smallest of the following angles:

(1) The angle of maximum righting

arm.

(2) The downflooding angle. (3) 40 degrees.

(c) The area under each righting arm curve must be at least 5.6 foot-degrees (1.72 meter-degrees) between the angles of 30 degrees and 40 degrees, or between 30 degrees and the downflooding angle if this angle is less than 40 degrees.

(d) The maximum righting arm shall occur at a heel of at least 25 degrees. (e) The righting arm curve must be positive to at least 60 degrees.

(f) For the purpose of this section, at each angle of heel, a vessel's righting arm may be calculated considering either

(1) The vessel is permitted to trim free until the trimming moment is zero; or

(2) The vessel does not trim as it heels.

Subpart F-Special Rules Pertaining to Ocean Thermal Energy Conversion Plantships and Floating Facilities

AUTHORITY: Pub. L. 96-320, 94 Stat. 974 (42 U.S.C. 9118, 9119(c), 9153 (a), (b)); 49 CFR 1.46 (ee).

§ 174.150 Specific applicability.

This subpart applies to each Ocean Thermal Energy Conversion plantship and floating facility that must meet Part 106 of this chapter.

§ 174.155 Stability requirements.

(a) Except as modified in this subpart, each plantship and floating facility must meet the following requirements in this subchapter:

(1) Section 170.085. (2) Section 170.090. (3) Section 170.120.

(4) Sections 170.174 through 170.190. (5) Sections 174.030 through 174.100. (b) Compliance with the remaining provisions in this subchapter is not required.

§ 174.160 Normal operating condition.

For the purpose of this subpart, "Normal operating condition” means a condition of the plantship or floating facility when loaded and arranged for producing energy or when in ocean transit.

§ 174.165 Tension tendon tethered facilities.

Each floating facility of the tension tendon tethered configuration must be designed so that it continually maintains a tension on each tendon when subjected to the forces described in § 174.055 of this subchapter.

§ 174.170 Stability test.

The stability test provided for in Subpart F of Part 170 of this subchapter is not required for a floating facility or plantship if it is shown to the satisfaction of the Commandant that, because of its configuration, testing of the facility or plantship is not practicable and the facility or plantship has inherent adequate stability by design.