Choosing The Right Rope For The Task

Many thanks to Captain Triko for this article.

The handling and application of rope on board yachts is a broad subject made all the more expansive by advances in technology. The place of rope, wire and spars on board a sailing vessel now more than ever requires well researched decisions which will take many factors into account. This investment in time to choose the ropes and lines best suited to the purpose on board ship will ultimately pay great dividends for owners and crews of racing and cruising boats alike.

Regardless of potential hull speeds the optimum hoisting and trimming of sails combines human factors i.e. seamanship and boat handling with the mechanics of effort and energy. The greatest limitation to achieving the optimums, assuming reasonably competent equipment use will be the physical properties of the equipment itself.

The point of this article is to not so much discuss the properties of rope in detail but to outline the benefits of which rope products best suit the budget and on board application.

There are some valuable generalizations about the use of rope and associated equipment i.e. blocks, jammers, winches, cleats etc. that remain current regardless of their construction and material properties.

• There is an important relationship between rope diameter and sheave/capstan diameter
• Mechanical advantage reduces effort
• Sunlight, dirt, moisture and mould affect the durability all ropes and lines
• Safe loading relies on secure fastening of hardware
• Safe Working Loads (SWL) information is where a system design begins

The all important selection of sailing equipment using weight to strength ratios has been arguably complicated by the increased availability and subsequent affordability of so called exotic and space age materials. The research and development of high modulus aramid fibers and yarns has lead to the commercial production of rope products such as Zylon and PBO.

Besides being very light for its strength these lines virtually eliminate stretch thus lending it to applications previously met with steel rod and steel wire. The crucial element in modern rig and sail design is weight and even on an agricultural cruising vessel the realization of weight minimization aloft is a big advantage. Less weight aloft means reduced heeling angles and less energy required in hoisting sails.

The introduction of low stretch braided ropes to the market has virtually bid farewell to the necessity for stainless steel wire halyards. However if you are considering replacing wire with low stretch braid it is crucial to check the profile of the masthead sheave as the wire sheave can damage a new braided rope when placed under load. Most braided rope manufacturers are now offering low stretch ropes and can supply data on the “ stretch “ and “ creep “ factors. The construction and properties and price of these ropes will vary from factory to factory but the one consistent element in their manufacture and supply is the requirement for oil based polymers.

Some on board applications require the opposite to no or low stretch. Anchor and mooring lines made up from nylon rope which can stretch up to 50% of its length reduces the shock loading in storm conditions. Three strand nylon ropes are not as abrasion resistant as braided or covered nylon ropes but are more abrasion resistant than three strand polyester ropes.

Somewhere between these two extremes of stretch is a multitude of choice in rope constructed to suit multipurpose applications. As stated earlier, the effort taken to find out the properties of the ropes and lines you are considering for your rig will have both physical and financial. Talk to your chandler and or rigger and use the internet (reputable rope manufacturers provide lots of load/weight/ strength/ stretch information) to help make these decisions.

And remember when hoisting or preparing to change sails, never let that halyard go without securing it to something on deck because it is a long way up that mast to retrieve a wayward halyard gone aloft. Sometimes the situation serves to remind us of the halyard we intended to replace at the start of the season. Not to mention the showdown between skipper and crew over whose fault and who is going aloft. Happy sailing starts and finishes with the wise and competent selection and use of rope.

Captain Tricko

One man band, sailorman, artist , writer, urger has lived aboard for ten years. My main accomplishment is recovery from frozen shoulder and having my name on a statue honoring Matthew Flinders in Hervey Bay. I also surf a bit and don’t mind a bit of hastily organised fishing.