Spinlock partners with TTI for rope advice

TTI specialises in design and engineering services in rope, textiles and related marine systems and it holds what is probably the largest independent library of fibre and rope technical data.

Perhaps through a lack of understanding, a highly tensioned fibre rope is seldom viewed by users as an engineerable structure.

However, as the experts know, the design of a modern high efficiency rope system requires the input of a number of very specialised disciplines.

There are tangible rewards in using such 'best practices' - high load efficiency, risks reduced, reliability maintained, and low weight for ease of handling.

These are attributes that enable highly competitive performance, for example, by the 'around the world' racing yachts in the management of their sail ropes (or 'halyards' as they are referred to by the enthusiasts).

"A requirement for an efficient means of gripping and releasing a highly tensioned modern synthetic fibre rope at any position along its length is by no means unique to yachting but the world's sailing industry needs are a most demanding driver of our product development", says Chris Hill, Design Director of Spinlock Limited.

His company designs and manufactures releasable rope cleats and clamps which are selected by most of the world's designers of the largest and fastest racing and super leisure yachts.

"As synthetic fibre rope makers produce ropes (and webbing) from fibres of ever greater tensile strength and durability, the same tensile load can be carried by ever smaller cross sectional areas." Ropeholding devices from this company consistently perform at the highest possible holding efficiencies so far achieved (around 52% of rope ultimate breaking load), a capability that is required whether the rope is new or well used, wet with rain or seawater, or dry.

This has also been achieved over a wide range of materials where friction and wear properties can be significantly different placing an extra burden on the clamp.

There is the additional complexity of the different types of rope construction which, under load, can give different transverse stiffness or put another way, the ability of the rope to hold a circular shape under side loading.

"Our design team has been continuously working towards higher efficiencies while maintaining load releasability.

We have introduced innovative mechanical features in a range of smart ergonomic device designs, as well as new constructions in aerospace-type materials for weight critical and hostile environmental applications.

We're especially pleased that one of our newest products (the plastic-bodied Powercleat), last year won two of the international yachting industry's top awards." Spinlock's Managing Director, Rodney Hogg, sees the expertise of his team benefiting other industries currently using tension systems which he suspects are technically underperforming.

"We know that modern synthetic fibre ropes offer tremendous advantages over their traditional rivals such as steel wire and natural fibre ropes.

We have proved that provided the materials and hardware have been designed as a technically integrated system, the benefits of the modern ropes that are now available (such as very light weight, high durability, low stretch, improved abrasion and UV resistance) can be realised.

We anticipate there can be through-life cost savings too, especially when taking into consideration the easier handleability of the excellent rope systems now available." The need for a 'systems' approach is emphasised by other issues arising from advanced rope technology.

Achieving a damage-free mechanical grip on the outside of a rope means concentrating on the capacity of the rope to resist crushing, bending and internal shear together with coefficients of friction.

Special lubrication (called the 'finish' in the rope industry) is applied to most synthetic fibres.

The life of a synthetic fibre rope in a dynamically loaded application is much improved by a 'finish', not only to reduce fibre-to-fibre friction and consequential internal wear in service but also to assist the rope making processes.

But that same lubrication works against the designer of the external gripping device.

Then there are ropes for special applications that feature external sleeves or coatings onto which the gripping devices must operate.

Rodney Hogg believes his expert device design team is especially well qualified in dealing with such obstacles.

Though Spinlock have worked with every leading rope maker for many years, he believes Spinlock's 'systems thinking' approach should now be moved into another gear.

This will enable them to meet the rising demand from rope users in other, non-marine industries who are now seeking to upgrade their systems and are actively considering using the latest technology.

Spinlock has established a strategic partnership with Tension Technology International Limited (TTI), an independent consultancy which specialises in design and engineering services in rope, textiles and related marine systems.

TTI is a leading advisor to clients in a wide range of industries around the world and it holds what is probably the largest independent library of fibre and rope technical data.

Its consultants include a number of academic specialists as well as former senior managers from the rope and textile manufacturing industries.

Steve Banfield, Managing Director of TTI, comments.

"Our work for clients on tension system applications often reveals that the potential of modern ropes is not fully appreciated or achieved.

With Spinlock, TTI can offer a unique industrial rope system design and solution service through a fully integrated approach involving world class specialists.

We know a number of industries who would gain significant benefit from such technology transfer and sharing.

We are excited at the new opportunities for industrial rope systems promised by the new facility.".

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