Which rope material tends to float when used as a rope?

• A. Manila
• B. Polyethylene
• C. Hemp
• D. Natural fiber rope

Answer: (B)

Buoyancy depends on the rope’s density relative to water and how much water it absorbs. Polyethylene is a light, hydrophobic polymer with a density below that of water and little water absorption, so it stays lighter than the surrounding water and tends to ride on the surface. Natural-fiber ropes like Manila, hemp, or other natural fibers absorb water and are denser than water, so they become heavier as they take on moisture and usually sink rather than float.