Four sizes cover a broad load range
Ronstan's new family begins with an 80mm sheave model rated to a 3,000kg maximum working load and extends through 100mm and 120mm versions to a 140mm unit rated to 9,000kg. The blocks are intended for running halyards and control lines through spars where line direction changes under substantial static and dynamic loads.
For leisure-yacht owners, correct sizing is more important than simply choosing the strongest unit available. Line diameter, expected load, installation space, lead angle and the structure carrying the block all need to be considered together when specifying or replacing deck and spar hardware.
Bearing design targets friction under load
Each block uses an anodised aluminium-alloy sheave rotating on Ronstan's proprietary self-lubricating composite bearing. Acetal ball thrust bearings are used to control side loading, while the housings are hard-anodised aluminium and the hub is Grade 316 stainless steel.
Reducing friction at an exit point can improve sail handling and help limit wear on expensive ropes, particularly where loaded lines change direction sharply. The benefit still depends on fair line leads and proper installation, because even high-quality hardware can suffer accelerated wear if a rope is allowed to rub against cheeks, spar edges or fittings.
Rope sizes extend into larger keelboat applications
The four models accommodate rope diameters from 14mm to 20mm, placing the range above the loads normally seen on small dinghies and into performance and cruising keelboat territory. Ronstan positions the products for both modern race-oriented installations and cruising yachts where durability and dependable operation are priorities.
Many leisure sailing yachts below 12 metres use smaller lines than the upper end of this range, but heavily loaded halyards, control systems and retrofit projects can still demand substantial hardware. Owners should use manufacturer load data and professional rigging advice rather than estimating loads from rope diameter alone.
A practical upgrade rather than a cosmetic one
Exit blocks are largely hidden compared with winches, displays or deck furniture, yet they influence how smoothly running rigging works every time a sail is hoisted, reefed or adjusted. Worn sheaves, damaged bearings or poor alignment can increase effort and shorten rope life even when the rest of the deck hardware appears sound.
For owners planning a rig refit, the new Ronstan range adds another high-load option that can be matched to the actual duty of each line. Inspection of the surrounding spar structure and fastenings should form part of any replacement, particularly where an older fitting has shown movement, corrosion or signs of overload.
Official sources: www.ronstan.com.