Windlasses and capstans are nowadays ubiquitous on boat foredecks, and powered motors are the almost the norm. Smaller vessels can manage with manually powered versions (and a fit crew). With larger vessels, although the windlass may have a manual back-up, the deployed anchor and rode is heavy and difficult to manage. As such reliability and performance are very important – like all anchoring equipment, a windlass qualifies as a safety device.
Technically speaking, the term "windlass" refers to horizontally oriented winches. Vertical designs are traditionally known as "capstans". However, it has become the case that "windlass" is commonly used to refer to both, with the orientation explicitly stated if necessary.
Horizontal windlasses operate via a horizontal shaft which carries wheels for chain and/or rope on either side. This essentially provides two winches in one and a great deal of flexibility. However, these wheels offer only one orientation laterally, which means they must be correctly aligned with the bow-rollers or hawsepipes, and ropes run through fairleads must be redirected with pulleys. Some windlasses also suffer slightly from the fact that the chain running from the bow-roller, over the gypsy, and down into a chain locker does not occupy much of a sector on the gypsy, thus giving it less 'grip'. A good spurling pipe design can compensate for this disadvantage.
Vertical capstans on the other hand do not offer two separate wheels. Chain can be run around the gypsy for a much larger sector than on a capstan's wildcat, giving it a better grip on the chain. However this advantage of 'half sector wrap' means that the chain being matched to the gypsy is all the more critical, as any minor discrepancy is amplified by the number of links engaged at any one time.
The spurling pipe configuration necessary for a vertical capstan means that chain is not 'peeled' off the gypsy as efficiently as with a horizontal windlass (where the weight of chain suspended down into the chain locker strips the chain wheel efficiently). A vertical capstan relies entirely on a chain stripper, which means they are more prone to jamming. All in all, they tend to be less versatile than a good horizontal installation.
In summary, horizontal windlasses are recommended as the more practical option, and they are the more prevalent on serious offshore cruising boats. In the world of production boats, a clean deck profile is commonly considered desirable, and vertical capstans are frequently chosen for their aesthetic design rather than practical benefits.
Because of the inherent configuration, horizontal windlasses make use of machinery that can be integrated in the main unit, which has the consequence that the mechanics can be kept above-deck. Vertical capstans use a vertical shaft, with the motor and gearbox situated below the winch unit, which usually means a position below the deck. Rather than protecting the equipment from the marine environment, this tends to end up placing it in the damp and hostile surroundings of a chain locker or forepeak, whereas the horizontal windlass can be sealed and self-contained.
It is necessary on most vessels to pull both chain and rope. The rope drum, or warping head, can be a dedicated wheel. The chain is pulled by a chain-wheel known as a gypsy or "wildcat".
The chain size and the gypsy must match each other closely, and quality chain with consistent links is important. Any variations will ensure faster and more damaging wear on both chain and gypsy, and can create problems during operation, particularly during fast deployment, when the chain could leave the gypsy entirely. It is important to maintain good control when running out ground tackle, particularly in deep water.
In modern times, with the increasing popularity and accessibility of recreational yachting and power-boating, automatic rope/chain gypsies have become popular – these are designed to firstly pull chain, then handle the transition to rope without operator interference. These systems vary in dependability and always impart a restriction on both the combination of possible chain and rope sizes, and the type of rope which may be used.
Electronic chain counters may be installed on the gypsy, in order to allow a cockpit display unit to track how much chain has been deployed. Whether automatic or manual, it is necessary to have some system to measure the amount of rode let out. For a look at some techniques to use while operating the windlass, refer to counting chain.
Adequate power and the capability to retrieve the tackle and anchor safely and efficiently is very important.
Some boaters like to push the boundaries of a manual system, using either a manual windlass or no windlass at all on vessels which are large enough that they really require some mechanized capability. This can have the unfortunate consequence that their choice of size of tackle and anchor size is affected, by a motivation to minimize weight. This is not a good input to the decision regarding the size of ground tackle being used, which rather should be entirely defined by the vessel size and intended usage. It should be accepted that the anchor and rode must be selected according to requirements, and that the equipment to handle it must then be selected according to needs. Anything else is a compromise to the safety and security of the boat and crew.
Only modern vessels have onboard energy supplies – ships in the old days have always required manual power. Capstans were the norm then even on large ships, as the vertical orientation lent itself to being 'walked' around by sailors.
Powered solutions on modern boats consist of electric and hydraulic motors. Electrics are convenient and relatively cheap, but hydraulics prove more efficient and powerful on all but small boats.
Manufacturers provide the power capability of their windlasses in terms of wattage, but the true lifting capability is more important and cannot be accurately gauged by only power, as it is affected by gearing and other factors. Windlasses should therefore be specified and rated according not to their "watts", but to their effective working pulling power.
For any given vessel, at a bare minimum windlasses should be capable of lifting the anchor and all its rode deployed at once and hanging suspended. Although undesirable, in more extreme weather the windlass can sometimes be required to pull the boat up to the anchor without much effective assistance from the vessel's engine. The required force should be attainable within the windlass' rated working pull, not its maximum pull.
Power cabling running to electric windlasses should be sized to eliminate voltage drop at stall load.
Rocna owners should not back down on their anchors during setting while the rode remains held by only the windlass. A chain stop should be in use, or the load can be taken up by a spring line – or, at the very least, the gypsy can be set to slip if under load severe enough to bend the windlass shaft. Most windlass shafts which are sized to handle the pull power of the windlass only, and will not endure the shock of a boat moving aft even slowly being stopped suddenly by rigid chain and a highly efficient anchor.