Which type of rope is known to lose strength when wet?

Nylon ropes are known to lose strength when they are wet due to the way the fibers are structured and their inherent properties. When nylon absorbs water, it can stretch more than it does when dry. This stretch can lead to a reduction in the rope's overall strength, particularly when exposed to dynamic loads, which may occur during rescue operations.

In contrast, other synthetic fibers, like polyester, tend to maintain their strength better when wet. Polyester ropes are often used in situations where moisture is likely, as they have lower water absorption and better resistance to UV light, making them more durable in wet environments. Polypropylene floats and has minimal water absorption, while natural fiber ropes, such as those made from manila or sisal, can degrade over time when exposed to moisture and should be used with caution in wet conditions, but they do not exhibit the same type of strength loss as nylon when wet.

Thus, understanding the properties of nylon helps rescuers make informed decisions about equipment selection, particularly in scenarios where water exposure can be a factor.