Rigging
Calculating parts of line
Multiplier
Multiplier = Total required line pullAvailable single line pull
- Divide the total required line pull by the available single line pull to get the multiplier.
- In the column for your sheave type, find the first value greater than the multiplier.
- The number of parts of line in that row is the number required.
| Parts of line | Nylatron sheaves | Bronze bushed sheaves | Roller bearing sheaves |
|---|---|---|---|
| 2 | 1.86 | 1.91 | 1.96 |
| 3 | 2.58 | 2.76 | 2.88 |
| 4 | 3.16 | 3.53 | 3.77 |
| 5 | 3.60 | 4.24 | 4.63 |
| 6 | 3.90 | 4.89 | 5.45 |
| 7 | — | 5.48 | 6.24 |
| 8 | — | 6.03 | 7.00 |
Multiplier values by parts of line and sheave type. Nylatron sheaves are not listed beyond 6 parts.
Worked example
Total required line pull is 7,400 lbs; available single line pull is 2,000 lbs.
7,400 lbs ÷ 2,000 lbs = 3.70 multiplier
- Nylatron sheaves: the first value above 3.70 is 3.90 → 6 parts of line
- Bronze bushed sheaves: the first value above 3.70 is 4.24 → 5 parts of line
- Roller bearing sheaves: the first value above 3.70 is 3.77 → 4 parts of line
Rig 6 parts with Nylatron sheaves, 5 with bronze bushed sheaves, or 4 with roller bearing sheaves.
What else changes
Multiple parts of line also change how much rope the drum must hold: drum capacity must increase to take the extra line used in the rigging. See Travel Distance.
Not sure what pull you need? Start with Line Pull.