Rope clutches are an important part of todays racing sailboat and even cruising sailboats. They allow us to lock off a halyard for the main or jib and even spinnaker without the need for a winch to be taken up.
Rope Clutches are the best option for controlling high load lines such as halyards. The clutch holds the line firm yet allows for quick and easy adjustment when needed. Rope clutches are available in several rope diameters from 4-14mm. They are also available in one, two, or three combinations They can also be found for horizontal mounting. Rope Clutches can be used for not just halyards but for tack Lines, furler Lines and any line that needs to be cleated.
Older versions of the Clutch (sometimes called stoppers) had a hard time opening under high load. They also slipped under load, and were tearing the covers off of good lines, But over the years incremental improvements have made Rope Clutches dependable devices. Still some problems occur; slippage can still a problem and so is rope damage, but to a much lesser degree.
So now we have a rope clutch that will hold the line fast, allow easy trimming, and yet gives quick release under load.
How to operate a Rope Clutch
First feed the halyard through the clutch with the clutch fully open. If the halyard has a Flemish eye, (small loop of whipping on the end) use this to pull the halyard through with a messenger line. Next read the instructions from the manufacturer on how to operate the clutch.
Hoisting the sail; leave the clutch open and take the halyard round the winch. Hoist the sail using the winch or pull hand over hand. Once the sail is up, the final tension is achieved with the winch. Once you have your desired tension close the clutch by pulling the handle flat all the way down. If the winch is needed for another application you can take the halyard off the winch.
For max holding power; tension the halyard with the Clutch “OPEN”. It is possible to tension the halyard without opening the clutch, but the clutch will not have as much holding power as if the clutch is opened.
Lowering the sail; Put the halyard around the winch and pull the halyard hand tight. Now you can open the clutch and then ease the sail down by hand. Sometimes if you have a very high load on the clutch, you can take a little tension off the clutch, by using the winch, before you open it.
It is kinder on the halyard if you taking up tension on a winch before releasing the load, just releasing the load the shock loading can damage the cover of the halyard.
How a Rope Clutch works
The Rope Clutch uses a toothed Cam controlled by a Handle. When the handle is pushed down the Cam is pressured against the rope and the toothed plate underneath. The spring pulls the Cam off the rope when the handle is pulled up and pushed forward. Clever mechanical advantages between the handle and the cams provide far greater compression over pervious clutches.
Slip is an inevitable side effect of rope Clutches and for the cams to work the need to pressure against the line which compresses with this pressure. Spinlock says 1 inch of slip is not unusual. For more on Clutch Slip see the section below.
Rope Clutch operation
In this position the halyard is held fast. To release the halyard lift the handle and push forward.
Note a Lewmar Rope Clutch has the handle the opposite way round
Rope Clutch Manufacturers
Spinlock, Antal, Lewmar, Garhauer, EasyLock and Barton. If we have focused on Spinlock too much it is because we feel they are the best and are the market leaders. Antal and Lewmar also have a very good reputation.
Lewmar Rope Clutch
Lewmar’s Rope Clutch works in a different way. The handle is pulled away from the line opposite to the Spinlock.
Also the gripping mechanism is different.
Lewmar’s description; Lewmar’s non-cam clutch has a series of in-line, parallel rings hinged at the base. A line is run through the rings and then the rings are tilted with a single lever connecting the rings. When tilted, the rings force the line to snake through them, creating friction to hold the line securely.
Antal Rope Clutch
Antal Rope clutches have even another method to providing grip. The Antal clutch cam is V shaped and this provides a bit more contact area for the cam to press against the rope.
A Rope Jammer is not a Rope Clutch. With a Jammer a line cannot be simply released when it is under a heavy load. The line must be taken to a winch and then the line tensioned and only then can the handle of the jammer can be pulled out. The picture right shows a Spinlock Jammer. These are good for lines that are set for long periods, such as a halyard for a furler on a big boat.
Rope Clutch Slippage
Excessive slippage is one of the most common complaints with Rope clutches. Rope slippage is when the clutch is closed and the line is taken off the winch and now the clutch is taking 100% of the load.
The line does have some normal slip (Spinlock says 1 inch is normal) due to the cam pushing down and settling of the line. Once it has settled you should not see any more slippage. Slippage is different from the stretch in the line or halyard. You can measure slip, by marking the halyard when the line is still on the winch and then noting where the mark is after the line has been released from the winch.
Ways to reduce rope slippage
- Tension line with Clutch OPEN
- When closing the clutch, ease the line SLOWLY off the winch, so you gradually load the clutch
- Loading the clutch with a jerk will increase slip
- Use a Line Diameter on the upper end for the clutch.
- as lines get more high tech they become smaller in diameter, which hinders their performance in the clutch
- Type of line used
- Loosely covered lines are going to flatten more and hence slip more
- Denser firmer high tech lines tend to sip less
- Compare clutch loads to your needs
- The Spinlock XAS or XTS works for similar line diameters but the
- XTS has higher load capability see below
- Replace worn Cams or upgrade Cams.
- Coat the halyard; Spinlock RP25 rope coating improves line grip and life
- If your halyard is too small in Diameter you can use Core bulking or
- Add extra cover to help. Talk to your Rigger.
- Wash clutch fresh water
Rope Clutch Loads
Spinlock Rope clutch, line diameter, Load
Match your line loads to rope diameter and clutch size.
- XAS, 4-8mm, 180-450kg, Lower Load, Racing yachts up to 27ft and cruising yachts up to 35ft
- XTS, 6-10mm, 280-700kg, Mid Load Clutch
- ACS, 8-14mm, 500-1000kg, Mid Load Clutch
- XX, 8-12mm, 900-1800kg, High Load
- XXC, 8-12mm, 1200-2350kg, Ultra High performance
Rope Clutch Position & Mounting
Typically the clutch is positioned in front of a winch, such as a halyard winch. The angle from the clutch to the winch should be as close to a straight line as possible and under 10 degrees. The halyard is tensioned by using the winch, after opening the clutch lever. When the halyard is at its desired tension the clutch lever is closed. If the angle from the clutch to the winch is over a few degrees the clutches can be raised with a block of Delrin or G10 or Starboard
The picture shows a bank of clutches in front of a winch. This is a common setup and allows several lines to be used by a single winch. For best use the high load halyards should be in the middle of the bank so they have the least deflection when loaded on the winch. Lighter load lines can be used on the outside of the bank.
The spinlock fairlead can help deflect a line to a winch and still have the line in line with the clutch. You can also use halyard Organizers.
Points to consider when choosing a Rope Clutch
For maximum holding, tension the line with the clutch open
Check you line size and match to the high end for the clutch
Size the clutch to the loading you have on your halyard or line
Make sure the line into and out of the clutch is no more than 8-10 degrees out of alignment