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If you would like more information on furling systems in general, please feel free to download our detailed "Furling System - Overview" document.
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But this flexibility does come at a premium price.īottom Up Furler product overview - photo © KZ Marine Group.However, one good example is KZ Race Furlers from New Zealand where every unit is available with a range of jaw sizes - to allow a smaller SWL unit with a larger than normal jaw width to accommodate the larger thimble.Only a small number of manufacturers appear to have optimised their ranges for the specific needs of top-down furling.This drives bigger thimble widths which often forces you to buy a larger furing unit than is required on pure SWL requirements. However, cable sizes are always bigger in diameter relative to bottom-up cables.Loads are much smaller for top-down furling and therefore you should be able to go down a size.Despite the obvious choice of whether to go for a dedicated top-down furling unit, Top-down furling has other consequences on unit size.It is by no means guaranteed that this distance is enough to accommodate your thimble/cable. the distance from the pin to the back of the jaw. Various jaw widths and pin sizes are available across the different unit manufacturers, but this will limit your choice to a few suitable units.If so, the thimble width on your furling cable is critical to the specification of the unit.Do you have an existing sail / furling cable?.Due to the significantly smaller sail areas relative to code zeros and gennakers, on the same boat, Staysail furlers can often be a size range.If you have a multihull this will almost always push you into the next category up due to the increased stability and therefore, loads.If you have a particularly heavy displacement boat and/or particularly large and powerful sail, then you might consider a slightly larger unit.See table below:Īs an example, if you have a 46ft boat you should be looking for a furling unit with a SWL of 2500-3000 kg, whilst a 50-53 ft boat might require something in the 4000 kg range. Summarising the data manufacturers provides an initial guide to required SWL based on your boat size.
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It is possible to generalise, based on boat size, to get a ballpark SWL and then consider several variables to guide your final decision. Unfortunately, few, if any, people really know the SWL of their forestay or their Code zero tack load.!? The correct method for specifying a unit is by the Safe Working Load (SWL) and this is the one consistently available piece of information, across all manufacturers. How do I choose the right code zero or gennaker furling unit for my boat? Data from eight well-known manufacturers is reviewed and conclusions drawn to help guide you to an appropriate unit for your needs.Ī quick review of the available data will tell you that sizing the correct furling unit for your boat is NOT an exact science!
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