Sections: [Nylon, Polyester and Polypropylene Ropes] [Rope Cleats] [Shackles]
The important factor to consider when purchasing ropes, cleats and shackles is that it is the correct design and strength for its intended application. These products have safe working load figures so knowing the working loads they will have to cope with it, makes it an easy choice. Otherwise seek professional advice or look at the size of rope or shackle used in a similar application on a boat of comparative size to your own.
Nylon, polyester and polypropylene ropes have universal marine applications, and the two major forms of lay-up (rope structure) are 3-strand and 9-plait. There are ropes which have an inner core made of low stretch polyester, such as Kevlar, Spectra or Dyneema, and are used for spinnaker sheets and runner tails.
The basic 3-strand polypropylene rope has good abrasion resistance and will float, making it the ideal mooring rope.
Its resistance to degradation by sunlight enhances its longevity. 3-strand nylon can be used for mooring ropes as it also floats, and has a hairy finish which helps in knotting. Lightweight 3-strand nylon rope sometimes is used for halyard tails, but does not stand high loads.
The plaited rope range starts with plaited polypropylene and is a soft and flexible floating rope suitable for sheets in small yachts. Multiplait nylon is strong but has a tendency to stretch making it unsuitable for sheets but can absorb shock loads, making it an ideal anchor warp.
Most yacht applications utilize a multiplait polyester rope where the two main types are a pre-stretched rope and the other a hard-finish, close-knit braid. ‘Hard finish' means that each strand is woven with a lot of twist.
The pre-stretched type is the choice for ropes under constant tension such as controls lines and sheets with its matt finish making it ideal for ease of handling. The hard-finish braid is the perfect for sheets and halyards, where low stretch and high strength are essential.
The ‘exotics’ of which the Kevlar-cored polyester is one have very low stretch but they are expensive. They are widespread in their use on racing yachts, where expense is not a primary consideration where their applications include running rigging and control lines. The latest of these is Dyneema, specifically designed for high load applications with low stretch the ability to turn tight corners.
The rope cleat function is to hold a rope from slipping, and come in three principal designs: the two armed deck cleat, the cam cleat and the clam cleat. The deck cleat is the simplest, having no moving parts and requiring a rope to be wrapped around it and clove hitched across it. This cleat is used for securing genoa sheets, halyards and mooring ropes, and made of acetal resin or high magnesium-content aluminium alloy.
The moving jaws of the cam cleat are controlled by a spring and grip the rope to prevent it slipping. Wide varieties of cam cleat are available, and sometimes have fairleads to aid handling. The cam cleat should be chosen to accept the size of rope and it should be capable of releasing the rope quickly when need be.
The cam cleat is used for those control lines needing frequent adjustment such as a mainsheet system where a cam cleat is incorporated into a multiblock system. Cam cleats are used to secure jib sheets on yachts of 28 feet or below providing a quick-acting system.
Clam cleats hold the ropes in a ribbed slot and therefore have no moving parts. Construction is of plastic or aluminium and a variety of sizes suit the rope diameters commonly in use. This cleat is perfectly suited to securing halyards and control lines such as the kicking strap.
Rope clutches and sheet jammers are be used to secure ropes and racing yachts usually have a row of rope clutches affixed on their coach roofs, and sheet jammers for genoa sheet turning blocks to allow the sheet to be secured when changing sheets.
Shackles are available in two main forms, the strip and the polished steel forged shackle. Shackles are available with captive pins, and are used to attach the sail on main halyards. They are designed to specific breaking loads, and other design points are the pin diameter, the width of the shackle and the length. Strip shackles have less practical application on a yacht than forged shackles, which are more able to withstand high working loads.