Yacht Winches - Snubbing Winch - Mechanical Advantage

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Yacht winches control the various ropes, wires and chains involved in yacht sailing and are either manual or powered. Used for hoisting, reefing and trimming sails, hoisting crewmen for rigging checks, tensioning parts of the rigging, hauling mooring lines and controlling boom angles, and lifting anchors, dinghies, keels and gangways .

Snubbing Winch

The smallest design is the 'snubbing winch' and is designed to rotate in one direction and ratchet-lock in the other. Making a few turns of a loaded rope around the drum will sustain a high load through friction on the drum surface maintained by light tension by the hand on the loose 'tail' of the rope.

The snubbing winch rotates when the rope is pulled and gains rope from the loaded end. When the tension is eased this allows the turns to slip on the drum, so that the loaded rope is paid out. With control it can be stopped again (snubbed) by restoring the tail tension. A greater force can be applied by fitting a handle at the centre of the winch to provide leverage.

Mechanical Advantage

A mechanical advantage is obtained by employing two or three levels of gearing between the handle and the drum still leaving the handle and the drum on the same rotational axis.

Headsails are trimmed through ropes (sheets) running to two-speed winches. Turning the handle one way gives direct drive, and reversing it, after the load increases, gives a lower gearing, with the drum always rotating in the same direction. When the sail is set, the tail of the rope is cleated or alternatively, the loaded side is passed through a levered 'stopper' releasing the rope from the winch, making it available for other use.

Self Tailing Winch

A 'self-tailing' winch accommodates a circular groove into which the rope tail jams tensioning the rope but feeds out the rope as the drum rotates. Heavier loads are managed single handed, but the action is slightly slower than with two crewmen with the tasks of 'winding' and 'tailing'.

Coffee Grinder Winch

Three-speed yacht winches are used on larger yachts whereby the third speed is selected by a button, and released automatically at the first change of handle rotation, leaving the coffee grinder winch able to engage the other two gears.

The crews of larger racing yachts need a large amount of manual energy operating a single winch quickly with greatest ergonomic efficiency. On the coffee grinder winch, one or more vertical pedestals with large double handles are linked to big yacht winches enabling several crew to wind simultaneously, while one man is entirely responsible for the tailing.

The task of sheeting is the same both in large and in small boats with simple two-speed yacht winches. As a sail is tacked, the sheet is hauled under light load with a snubbing winch. As the sail fills, the load increases it becomes necessary to work down through the gears.

When it comes to yacht winch design, the racing sailor has different requirements from the cruising sailor. In racing, since only manual operation is allowed, the emphasis is on light weight, involving expensive materials like titanium and carbon fibre and optimum gearing. For cruising, durability and low maintenance are more essential, and larger yachts have electrical or hydraulic power reducing the dependence on multiple gears.

Reel winches hold all the line that they wind in on a simple drum, this technique is only suitable for thin line and was previously used

mainly for wire halyards which are unable to be tailed by hand. With the advent of newer fibres such as Kevlar, making ropes as strong as steel, the use of wire halyards is decreasing.

For the super yachts a new range of power 'captive' winches is emerging. Placed below the deck, the sheets are led to large drum reels or to a capstan drum and then onto separate drum stowage. This results in clear decks with trimming under electronic control from the helmsman's station.

Windlass

In yachts over 10 metres length overall, the anchor handling is by a powered windlass. It must be reversible for raising or lowering anchor, or have a lever-operated clutch to allow the cable to run out and be capable of handling either chain or rope. The rope passes over a smooth drum but the chain is gripped in a wheel called a 'gypsy'.

Traditional windlasses have two drums, one either side of the motor and gears and on a horizontal axis athwartships, with one side is used for rope and the other for chain.

On smaller craft a vertical drum in the form of the ancient capstan is now in vogue. It is efficient as the motor can be placed below deck, protected from seawater, with the profile of the winch above deck looking similar to a sheet winch. The gypsy occupies the lower section below the rope drum and the power and direction of rotation is controlled by footpads set flush in the deck.

Rope Blocks

Blocks, casings containing one or more pulley wheels, such as turning blocks and foot blocks, are used to change the directions of sheets and halyards, while other applications are arranged in combinations that provide mechanical advantage.

The mechanical advantage of a pulley system is the ratio of its output force to the amount of force applied to it. If a mainsheet system has a mechanical advantage of 8:1, then pulling on the mainsheet with a force of 1 kg results in a force of 8 kg being applied to the boom.