---
kind: "section"
citation: "46 C.F.R. § 119.425"
title: "46"
number: "119.425"
heading: "Engine exhaust cooling."
url: "https://uscodex.org/cfr/46/119.425"
---

# §119.425. Engine exhaust cooling.

- (a) Except as otherwise provided in this paragraph, all engine exhaust pipes must be water cooled.
  - (1) Vertical dry exhaust pipes are permissible if installed in compliance with §§ [116.405(c)](/cfr/46/116.405.md?p=c) and [116.970](/cfr/46/116.970.md) of this chapter.
  - (2) **Horizontal dry exhaust pipes are permitted only if—**
    - (i) They do not pass through living or berthing spaces;
    - (ii) They terminate above the deepest load waterline;
    - (iii) They are so arranged as to prevent entry of cold water from rough or boarding seas;
    - (iv) They are constructed of corrosion resisting material at the hull penetration; and
    - (v) They are installed in compliance with §§ [116.405(c)](/cfr/46/116.405.md?p=c) and [116.970](/cfr/46/116.970.md) of this chapter.
- (b) The exhaust pipe cooling water system must comply with the requirements of this paragraph.
  - (1) Water for cooling the exhaust pipe must be obtained from the engine cooling water system or a separate engine driven pump.
  - (2) Water for cooling an exhaust pipe, other than a vertical exhaust, must be injected into the exhaust system as near to the engine manifold as practicable. The water must pass through the entire length of the exhaust pipe.
  - (3) The part of the exhaust system between the point of cooling water injection and the engine manifold must be water-jacketed or effectively insulated and protected in compliance with §§ [116.400(b)](/cfr/46/116.400.md?p=b) and [116.970](/cfr/46/116.970.md) of this chapter.
  - (4) Each vertical exhaust pipe must be water-jacketed or suitably insulated between the engine manifold and the spark arrester required by [§ 119.430(g)](/cfr/46/119.430.md?p=g) of this part.
  - (5) When the exhaust cooling water system is separate from the engine cooling water system, a suitable warning device, visual or audible, must be installed at the operating station to indicate any reduction in normal water flow in the exhaust cooling system.
  - (6) A suitable hull strainer must be installed in the circulating raw water intake line for the exhaust cooling system.
- (c) Engine exhaust cooling systems built in accordance with the requirements of American Boat and Yacht Council (ABCY) P-1, “Installation of Exhaust Systems for Propulsion and Auxiliary Engines,” will be considered as meeting the requirements of this section.

## Notes

### Authority

Authority: 46 U.S.C. 2103, 3306; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; DHS Delegation No. 00170.1, Revision No. 01.3.

### Source

Source: CGD 85-080, 61 FR 922, Jan. 10, 1996, unless otherwise noted.