Lewmar offer 3 sizes of powerful and compact rotary drive units, which employ conventional chain and sproket connection to the steering system. The high efficiency, twin stage, epicyclic gearbox is grease filled, which allows mounting in any attitude. The wide mounting platform is slotted to aid chain tensioning. Rotary drives are generally used on cable and push-pull steering systems and it is necessary to calculate the correct driven sprocket, which is dependent on the turns (mechanical advantage) of the steering system. Lewmar can supply fully machined sprockets for your steering system in steel or stainless steel upon request, as well as chain and master links.