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Lighter, more versatile, nearly friction free

Yacht Racing Podcast

A complete redesign of Allen Brothers’ already excellent range of 40mm Dynamic Blocks delivers obvious benefits for a significantly wider range of boats and sailors.

Allen Brothers has completely redesigned its high performance 40mm Dynamic Blocks. The new models retain the stand out features of the previous range, including the ultra-low friction stainless steel bearing technology. However, other elements have been updated to create an impressively lightweight and strong product, which can easily handle the demands and loads experienced when racing high-performance modern dinghies and keel boats.

The new design has enabled Allen to produce more variations, with 33 models now available ranging from single to quad blocks, with or without beckets and cleats and with a variety of attachment methods to suit different applications across dinghies, keelboats and yachts.

The core of the product remains the company’s well-proven dynamic bearing system that’s also shared with the existing 20 to 60mm products in the range. This has twin rows of stainless-steel ball bearings that are held in cages to keep them separate so they don’t rub against each other. The bearings run on a stainless-steel axle.

‘Metal bearings roll faster than plastic will because it can’t deform under load. And what that means is there’s less friction,’ says Allen’s Ben Harden. ‘You also get a longer lasting product, essentially because the stainless steel is much less likely to get a flat spot or to wear out than plastic alternatives.’

The range is suitable for a wide range of applications in dinghies, keelboats and yachts, with the latter benefitting from development work in the very high-performance dinghy market. The 40mm Dynamic Block range is ideal for handheld control lines on yachts and keelboats, where line sizes are continuing to reduce. Here, the lack of friction in a product with its roots in the very highest echelons of dinghy racing pays dividends in reducing line loads. That in turn increases the number of functions that can be easily controlled by hand, which can then make manoeuvres quicker and easier.

Main image: Allen Brothers’ new generation of 40mm Dynamic Blocks are much lighter and a wider range of 33 models is available. They all have the same ultra-low friction stainless steel bearings.

Also ideal for lower load keelboat mainsheet systems, a key benefit is seen in lighter airs when the sheet can be eased without a crewmember needing to push against the boom. While Allen’s background is in competitive dinghy racing, the company has been progressively pushing into the keelboat and yacht racing worlds for some time, where it is becoming increasingly recognised for a growing range of high-performance products.

Investment in injection moulding tools has allowed the metal cheek straps or brackets previously used to hold the cleats, beckets and fiddle together to be replaced with a lighter glass loaded nylon. ‘Essentially it is still as strong as the metal was,’ says Harden, ‘so the maximum working loads and breaking loads haven’t changed.’ Depending on the model, working loads range from 80 to 750kg, while breaking loads vary from 540 to 1,500kg.

Yet the new blocks are also much lighter – a 40mm Single Tii-On model is only 34.5g – and the range has a more contemporary style. At the same time, Allen’s investment in tooling means many more variations that provide wider possibilities for different systems are offered. Double, triple and quadruple sheave blocks are all available with a lockable swivel shackle attachment that can be locked in 90-degree orientations, or removed to allow the block to rotate freely.

Similarly, single, double and triple sheave options are available with aluminium ball-bearing cam cleats mounted on an adjustable arm that can be set to match the sheeting angle. In addition, every block is designed with a large central hole that can be used as a tying off point for a becket, though there are also models that incorporate a conventional becket, as well as for rope attachment. Maximum line sizes vary from 6-10mm depending on the product.

The 40mm block is also offered with three sheave options. Standard Dynamic models have a sheave made of a lightweight engineering plastic, while the high load option has a stainless-steel sheave. A further upgrade is offered with the XHL extreme high load range, which adds a CNC machined aluminium side cheeks. Along with the twin rows of stainless-steel ball bearings, cage and axle, this creates a block with exceptional static load bearing abilities relative to its impressively compact size, without risk of damaging the dynamic performance of the ball bearings. This makes it ideal for use in vang cascades and halyard turning points, where static loads can be extremely high, but friction free dynamic performance is needed in low load situations.

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