46 C.F.R. § 108.159 Stairways and exterior inclined ladders.
Title 46 - Shipping
Each stairway, except a stairway in a machinery or storage space, and each exterior inclined ladder must be at least 70 centimeters (28 inches) wide with an angle of inclination from the horizontal of not more than 50 degrees, except that special consideration may be given to the installation if a 70 centimeters (28 inch) width is impracticable.
Title 46: Shipping
PART 108—DESIGN AND EQUIPMENT
Subpart B—Construction and Arrangement
Means of Escape
§ 108.159 Stairways and exterior inclined ladders.

