Snubberhead™

Probably more information than you ever wanted to know about anchor snubbers and bridles

The anchor snubber and bridle size calculator below is designed to provide directional estimates for optimal snubber line diameter and length for 3-strand nylon. The results indicate the diameter and length of line required to absorb the kinetic energy of the boat for the weight and speed provided.

- The top-half of the cell represents the load imposed as a percentage of the rope's minimum break strength. If the value is higher than the WLL you entered, this portion of the cell will be red.
- The lower-half of the cell represents the deceleration/acceleration of the boat as the snubber or bridle absorbs and releases the energy. The lower the value, the gentler the motion; the higher the value the more uncomfortable the motion. Green denotes gentle motion, yellow is uncomfortable and red is approaching snatch loads.
- Remember, the results reflect the snubber or bridle requirement for the boat speed entered - which should be worst-case. If the table states 30 feet or 10 meters is needed, that's for worst-case. Obviously, fair weather will not require a full 30'/10m deployment.
- Catamaran's should size up in diameter and length. See our Catamaran Anchor Bridles page for details.

The calculator uses the formula for kinetic energy, KE = 1/2 Mass X Velocity^{2}, to calculate the energy generated by the boat.

The capacity of the snubber or bridle to absorb the kinetic energy of the boat is calculated using the elastic potential energy formula
PE = 1/2 kx^{2} where k is the spring constant and x is the displacement. The spring constant is calculated using Hook's law k = F/x, where F
is the force needed to extend the spring and x is the displacement length. We use 10% elongation at 20% minimum break strength to determine
displacement.

The following deductions in strength are built into the calculator:

1. When wet, nylon's strength is reduced ~12%

2. Splicing reduces nylon's strength ~10%

3. Hard (or thimbled) eye reduces nylon's strength ~20%