A ship ladder, sometimes referred to as a ship’s stair or ship’s ladder, is a specific type commonly used on ships, as the name suggests, but is also used in other environments where space is limited. Ship ladders occupy a middle ground between traditional stairs and vertical ladders.
In non-marine applications, a ship ladder is used where space is limited and is steeper than stairs, yet not as steep as a vertical ladder.
A ship ladder typically has a steep incline, often between 50 and 70 degrees. The steps are designed with a tread that extends from one side of the ladder, which allows users to descend facing forward, unlike a typical ladder that must be descended backward. The steps are usually not as deep as stairs and often have open backs.
As of my knowledge cutoff in September 2021, OSHA (Occupational Safety and Health Administration) doesn’t provide specific guidance for ship ladders. Instead, they are covered under fixed ladder regulations (OSHA 1910.23), stair standards (1910.25), or alternating tread-type stairs standards (1910.25(e)) depending on their specific design and use case.
Some of the relevant standards might include:
- Guardrails: If the ship ladder is over 30 inches (76 cm), OSHA regulations require guardrails to protect against falls.
- Handrails: OSHA requires handrails on at least one side of a ship ladder. These handrails must withstand a force of 200 pounds applied in any direction.
- Design Strength: Like other fixed ladders, ship ladders must be designed to hold their maximum intended load.
- Clearance: There must be sufficient clearance when climbing the ladder. The exact clearance may depend on the specific design and use of the ship ladder.
- Tread: All treads must be reasonably slip-resistant, and the tread depth should be sufficient for safe climbing and descending.
- Angles: While ship ladders are steeper than most stairs, they must maintain a climbable angle. This will typically be somewhere between 50 and 70 degrees from the horizontal.
As regulations may have changed due to variations in local building codes and regulations, it’s always best to consult with a current, authoritative source or a professional engineer when designing or installing ship ladders.