46 CFR 161.006-4: Motor lifeboat searchlight construction requirements
Last reviewed: October 14, 2026
This section sets design and construction requirements for the motor lifeboat searchlight. It covers materials, parts, weight and height limits, wiring, lamp, housing, door, reflector, beam and marking. Several items refer to other sections or specifications for detail.
Applies toThe motor lifeboat searchlight.
What it says
The motor lifeboat searchlight must not be taller than 19 inches or heavier than 16 pounds, unless otherwise approved.
46 CFR 161.006-4(c)“The height of the motor lifeboat searchlight shall not exceed 19 inches and the weight shall not exceed 16 pounds, unless otherwise approved.”
The searchlight must be wired with a five-foot length of rubber-jacketed hard service flexible cord, Underwriters' Laboratories, Inc., Type S or equivalent, of a size not less than No. 16 AWG.
46 CFR 161.006-4(d)“The motor lifeboat searchlight shall be wired with a five-foot length of rubber-jacketed hard service flexible cord, Underwriters' Laboratories, Inc., Type S, or equivalent, of a size not less than No. 16 AWG.”
The searchlight must have a lamp of not less than 80 watts nor more than 100 watts, and a suitable lamp socket.
46 CFR 161.006-4(e)“The motor lifeboat searchlight shall be provided with a lamp of not less than 80 watts nor more than 100 watts, and a suitable lamp socket.”
The housing must move freely at least 60 degrees above and 20 degrees below the horizontal, and 360 degrees in a horizontal plane.
46 CFR 161.006-4(f)“The housing shall be capable of free movement of at least 60 degrees above and 20 degrees below the horizontal, and of a free movement of 360 degrees in a horizontal plane.”
The front door must be readily opened or removed without tools for relamping, and it must be waterproof when closed.
46 CFR 161.006-4(g)“A front door shall be attached to the housing in such a manner that it can be readily opened or removed, without the use of tools, for the purpose of relamping.”
The reflector must be paraboloidal and must furnish a minimum average illumination of 100 foot candles, measured as specified in § 161.006-5 (b) (2).
46 CFR 161.006-4(h)“The reflector shall furnish a minimum average illumination of 100 foot candles, when measured as specified in § 161.006-5 (b) (2).”
The beam must be at least 60 feet in diameter at 200 yards.
46 CFR 161.006-4(j)“The beam shall be at least 60 feet in diameter at 200 yards.”
The searchlight must have a permanent metallic name plate giving the manufacturer's name, type designation, and drawing number.
46 CFR 161.006-4(l)“The motor lifeboat searchlight shall be provided with a permanent metallic name plate giving the name of manufacturer, type designation, and drawing number.”
Common questions
What is the maximum weight of a motor lifeboat searchlight?
The weight must not exceed 16 pounds, unless otherwise approved. The height also must not exceed 19 inches.
“The height of the motor lifeboat searchlight shall not exceed 19 inches and the weight shall not exceed 16 pounds, unless otherwise approved.”
What lamp wattage must a motor lifeboat searchlight use?
It must have a lamp of not less than 80 watts nor more than 100 watts.
“The motor lifeboat searchlight shall be provided with a lamp of not less than 80 watts nor more than 100 watts, and a suitable lamp socket.”
What materials count as corrosion-resistant for a motor lifeboat searchlight?
Silver, corrosion-resisting steel, copper, brass, bronze and copper-nickel alloys are considered satisfactory corrosion-resistant materials within the intent of this subpart.
“Silver, corrosion-resisting steel, copper, brass, bronze and copper-nickel alloys are considered satisfactory corrosion-resistant materials within the intent of this subpart.”
How must the searchlight be marked?
It must have a permanent metallic name plate giving the name of manufacturer, type designation, and drawing number.
“The motor lifeboat searchlight shall be provided with a permanent metallic name plate giving the name of manufacturer, type designation, and drawing number.”
The text of 46 CFR 161.006-4
Electronic Code of Federal Regulations (eCFR), current as of March 31, 2026 · Read it on eCFR
Requirements
(a) Corrosion-resisting materials. Silver, corrosion-resisting steel, copper, brass, bronze and copper-nickel alloys are considered satisfactory corrosion-resistant materials within the intent of this subpart.
(b) Searchlight parts. The motor lifeboat searchlight shall, in general consist of the following parts:
Yoke and pedestal. Housing. Front door. Reflector. Lamp socket. Supply cable.
(c) Weight and dimensions. The height of the motor lifeboat searchlight shall not exceed 19 inches and the weight shall not exceed 16 pounds, unless otherwise approved.
(d) Wiring. The motor lifeboat searchlight shall be wired with a five-foot length of rubber-jacketed hard service flexible cord, Underwriters' Laboratories, Inc., Type S, or equivalent, of a size not less than No. 16 AWG. At the point where the cable enters the searchlight, a waterproof entrance bushing with packing gland and cord grip shall be provided.
(e) Lamp and socket. The motor lifeboat searchlight shall be provided with a lamp of not less than 80 watts nor more than 100 watts, and a suitable lamp socket. Means shall be provided for adjusting and securing the lamp socket at any position between the focal point and a point not less than 1/4 inch away from the focal point in either direction in the axis of the beam.
(f) Housing. The housing shall be constructed of brass, Federal Specification QQ-B-611, Composition E, copper alloy, or other suitable corrosion-resistant material as approved, of a thickness not less than No. 20 AWG. The housing shall be capable of free movement of at least 60 degrees above and 20 degrees below the horizontal, and of a free movement of 360 degrees in a horizontal plane. It shall be possible to lock the barrel in any desired position, vertically or horizontally, without the use of tools. A sturdy metal hand grip shall be provided at the back of the housing for housing-adjusting purposes.
(g) Front door. A front door shall be attached to the housing in such a manner that it can be readily opened or removed, without the use of tools, for the purpose of relamping. The door, when closed, shall be waterproof. Clear front door glass shall be used.
(h) Reflector. The reflector shall be paraboloidal. It shall be constructed of brass, Federal Specification QQ-B-611 Composition E, finished and with electroplated coatings of nickel and chromium in accordance with ASTM B 456 (incorporated by reference, see § 161.006-1), Service Condition 1, or as otherwise approved. The reflector shall furnish a minimum average illumination of 100 foot candles, when measured as specified in § 161.006-5 (b) (2).
(i) Yoke and pedestal. The yoke and pedestal shall be of rugged construction. The pedestal shall be suitable for bolting to a flat surface with not less than four 3/8-inch diameter bolts.
(j) Beam spread. The beam shall be at least 60 feet in diameter at 200 yards. The edge of the beam shall be defined as a point at which the intensity of the light is 10 percent of the maximum intensity.
(k) Bolts, nuts, and screws. Bolts and nuts shall conform to the requirements of Navy Department Specification 43B11. Screws shall conform to the requirements of Navy Department Specification 42S5.
(l) Name plate. The motor lifeboat searchlight shall be provided with a permanent metallic name plate giving the name of manufacturer, type designation, and drawing number.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of March 31, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.