Manufacturer part #: FR4
Manufacturer part #: FR4
Lighter and smaller than a conventional pulley block, ferrules have become a popular alternative for many applications where traditional blocks once ruled. Instead of rolling on a pulley sheave, the active line with a ferrule merely slides on the inside smooth surface of the ring. Another line is spliced around the ferrule for attaching it.
This attachment line is sometimes made as a loop that is luggage tagged onto a padeye or the toe rail. Frictional losses are not as big as one might think, especially when using low friction line such as dyneema. In addition to being lighter and less expensive than conventional blocks, ring ferrules are also less prone to failure since there are no pulleys to crack or bearings to foul.
Applications
Ferrules are ideal for applications such as barber haulers, spinnaker twings or other uses that have small turning angles and little line movement. They also work great for backstay adjusters when used in a high purchase cascade configuration. Ferrules start having frictional heating and wear problems when there is significant line movement so conventional pulleys are still better for applications such as mainsheet and halyard blocks.
Numerous sizes are available depending on the application and line size. Tylaska ferrules are also optionally available with prespliced dyneema attachment loops.
 | Features | American | Metric |
|---|---|---|---|
| Description | Ring Ferrule FR4 | ||
| A | 1/4 in | 6.4 mm | |
| B | 11/64 in | 4.4 mm | |
| C | 5/8 in | 15.7 mm | |
| D | 1/4 in | 6.4 mm | |
| E | 1/8 in | 3.1 mm | |
| Line Size | 5/32 in | 4 mm | |
| SWL | 600 lb | 275 kg | |
| Breaking Strength | 1200 lb | 550 kg | |
Manufacturer part #: FR4
Lighter and smaller than a conventional pulley block, ferrules have become a popular alternative for many applications where traditional blocks once ruled. Instead of rolling on a pulley sheave, the active line with a ferrule merely slides on the inside smooth surface of the ring. Another line is spliced around the ferrule for attaching it.
This attachment line is sometimes made as a loop that is luggage tagged onto a padeye or the toe rail. Frictional losses are not as big as one might think, especially when using low friction line such as dyneema. In addition to being lighter and less expensive than conventional blocks, ring ferrules are also less prone to failure since there are no pulleys to crack or bearings to foul.
Applications
Ferrules are ideal for applications such as barber haulers, spinnaker twings or other uses that have small turning angles and little line movement. They also work great for backstay adjusters when used in a high purchase cascade configuration. Ferrules start having frictional heating and wear problems when there is significant line movement so conventional pulleys are still better for applications such as mainsheet and halyard blocks.
Numerous sizes are available depending on the application and line size. Tylaska ferrules are also optionally available with prespliced dyneema attachment loops.