MANUAL CHAIN HOIST


RED ROOSTER DELIVERS MANUAL AND ELECTRIC SOLUTIONS


Project 1: Boatyard project – manual chain hoists A busy UK boatyard required reliable, high-capacity manual hoisting equipment to support the maintenance and repair of vessels hauled from the water via their existing slipway systems. These systems – two custom-built boat hoists rated at 40t and 10t respectively – have been in continuous operation for over 20 years, launching and recovering vessels up to 40t and 18m in length. To continue supporting these operations, the customer needed durable, corrosion-resistant manual lifting gear that could handle substantial loads in the harsh marine environment. Red Rooster Lifting supplied a set of Kito high-performance manual hoists to enhance the existing infrastructure. For the heavy-duty lifts they supplied four 15t Kito Manual chain-block hoists. These robustly constructed units have high-performance braking


systems – nickel-plated chains give increased corrosion resistance in the marine environment. For lighter lifts, four 3.2t Kito lever hoists were supplied. Lightweight and portable, these gave precise load control for adjusting and securing components during repair work or boat maintenance – especially useful during tight manoeuvring tasks on slippery or confined platforms.


Project 2: Hydropower – synchronised electric lifting A leading hydropower station operator contacted Red Rooster for a twin hook lifting solution for replacing two sluice gates. The gates regulate water levels and flow rates and required equipment with precise lifting and lowering capabilities, as well as reliable performance in a challenging aquatic environment. Red Rooster supplied two 5t Kito, model TWER2-050-IS electric twin- hook chain hoists. The design team incorporated custom features to handle the complexities of the project. Features of the hoists included synchronised lifting. Each hoist is equipped with an inverter for lifting and lowering of the twin hooks in phase. This not only gives accurate positioning of the sluice gate but also prevents load imbalance or damage during installation and removal. Nickel-plated load chains and stainless-steel bottom blocks were


provided for robust performance in the water-exposed conditions, and surfaces were epoxy-painted surfaces for protection against corrosion. For enhanced safety, thermal protectors were fitted to safeguard the hoists against overheating during prolonged operations. Upper and lower limit switches prevent over-travel, minimising the risk of equipment damage. The twin hook hoists have dual-speed lifting to precisely control the sluice gates; a counter hour meter tracks equipment use, allowing proactive maintenance planning, reducing the risk of unexpected breakdowns and extending the lifespan of the hoists. The span width between hooks is 3,048mm and the height of lift is 10m.


available on all William Hackett manual chain hoists as well. The principle, as explained by William


Hackett, is this: early lever hoists used a rachet and pawl system to hold the load-wheel and stop it reversing between pulls on the lever. The pawl was spring-loaded to keep it in contact with the rachet wheel. Failure of the pawl to engage – for example, if the spring were to fracture – would obviously have potentially disastrous results, with the weight of the load causing the rachet wheel to spin rapidly backwards out of control. Such single-point catastrophic failure are, of course, to be avoided, especially in the hazardous marine environment. Twin pawls, mounted diametrically opposite each other on the ratchet wheel, reduce this risk and are now standard in lever hoists. Even so, risk from a spring failure remains.


William Hackett have overcome this


problem with a four-pawl design that does not rely on springs. Instead, the pawls are arranged in semi-interlocking pairs and each pair operates rather like a clock escapement – when one of the pawls disengages, it pushes against the other pawl to make it engage with the rachet. The system is fitted with springs, as a redundancy and a back-up, but they are not necessary for its operation and a snapped spring does not result in the system failing. The company makes manual hoists of


up to 50t capacity. This, of course, is a huge weight for a human operator to lift, but it can be done – as elementary school physics courses in mechanical advantage show, a sheave-and- pulley system where the load is supported by two falls of rope requires only half the force to lift it when compared to a load on one fall,


therefore a 5t pull will raise a 10t load. “There are 20 falls of chain in our 50t manual chain hoist, meaning there are 10 sheaves that the load chain get pulled around. This mechanical advantage essentially suggests that it should take the same effort to operate a 50t hoist as it does a 5t hoist,” says Josh Burgess, operations director of William Hackett. In practice, friction and other effects come into play. The effort required to operate a 50t hoist is actually around 500N, which is about 50kg force. But it can be done – though ideally with two strong men at the chain rather than one. There is a downside – the greater the mechanical advantage, the slower the speed. That 50t load will be raised very slowly indeed. And lifting or lowering the unloaded hook will be similarly slow and tedious, which is why they have their Dual Speed chain hoist. When the hoist is loaded, the lifting and lowering speed


www.hoistmagazine.com | June 2025 | 23


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