Mar 26, 2012, 9:02 AM
Post #1 of 2
Karver Top Down Furler Video
Karver: Top Down Spinnaker Furler
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Karver Systems recently developed a continuous line furler that will not only furl Code sails, but will furl asymmetrical spinnakers as well. They call it a Top Down Spinnaker Furler. Since Code sails don’t fly off a stay, they have an anti-torsion rope inside the luff of the sail. The head of the sail is lashed to one end of the rope, and the tack is lashed to the other end. This rope essentially becomes the stay. The ropes usually have a uni-directional aramid core with an over braided cover which gives them their anti-torsion qualities. It performs two functions. First it enables you to put a large amount of tension on the luff which gives the sail a good flying shape. Secondly, it enables you to furl the sail by not allowing twist (or torque) to build up in the rope while rolling up the sail.
In order to furl an asymmetrical spinnaker an anti-torsion rope is also required. However, with this sail the rope is external. The head of the spinnaker is lashed to the one end of the rope which plugs into the top swivel. The other end of the rope plugs into the tack fork of the furler drum. The tack of the sail is attached to a ball bear swivel that is located just below the tack fork. When the sail is flying, its flying as it normally would independent of the rope. The tension of the rope has no bearing on how the spinnaker flies. When you want to furl the spinnaker, rope tension becomes critical for the same reason it does with the Codes sails. When the furler drum turns the rope catches the head of the spinnaker which then starts to wrap around it. As this is happening the tack of the sail remains stationary due to the tack swivel. This is what creates “Top Down Furling”.
The keys to the system working properly are proper rope tension, and controlling the sheet. When you want to furl, you need to turn the boat deep and give the sheet a large ease to unload the sail. Once you see the sail start to wrap itself on the rope, you need to pull back on the sheet, so as to not let too much sail cloth forward into the rope. With a little bit of practice, you can even furl an big A2 in a similar fashion to a rolled up Code sail.
Some of the benefits of this package: The Marlow Rope is priced very reasonably (compared to other products on the market), and performs very well. It can be finished easily with a sewing machine which keeps the finishing costs down, and allows for a fairly quick delivery of the finished rope. The full line of KSF Furlers can work with both code sails and spinnakers without any modification. Plug and play. For racers, you can set the system up with an adjustable tack line. This allows you to rotate the kite to windward when deep running. When configured this way, you can only do inside jibes. If you don’t have the furler on a sprit, you can still set up an adjustable tack line, but you will have to furl and unfurl while jibing.
For additional information please contact:
Euro Marine Trading, Inc.