The Prusik cord should be approximately which fraction of the main line's diameter?

The Prusik cord should be approximately which fraction of the main line's diameter?

• A. 1/2-5/8
• B. 2/3-3/4
• C. 3/4-1
• D. 1/3-1/2

Answer: (B)

Sizing the Prusik cord relative to the main line is about getting the right balance between grip and release. The hitch relies on friction: when loaded, the Prusik should bite enough to hold the rope, but it must still be able to slide along the main line when you ease tension. If the Prusik cord is too small, it won’t grab firmly and can slip under load. If it’s too large, it may grip too aggressively, making it hard to slide and potentially causing jamming or excessive wear. The best balance is a Prusik cord roughly two-thirds to three-quarters of the main line’s diameter, which provides reliable bite while still allowing smooth movement and release. For example, on an 8–9 mm rope, a 5–6 mm Prusik cord fits this ratio.

Sizing the Prusik cord relative to the main line is about getting the right balance between grip and release. The hitch relies on friction: when loaded, the Prusik should bite enough to hold the rope, but it must still be able to slide along the main line when you ease tension. If the Prusik cord is too small, it won’t grab firmly and can slip under load. If it’s too large, it may grip too aggressively, making it hard to slide and potentially causing jamming or excessive wear. The best balance is a Prusik cord roughly two-thirds to three-quarters of the main line’s diameter, which provides reliable bite while still allowing smooth movement and release. For example, on an 8–9 mm rope, a 5–6 mm Prusik cord fits this ratio.