Spinnaker sock
ATN Doyle

That statement is particularly true regarding the spinnaker. The problem is not to hoist the sail but to get it back on the boat. That's when the spinnaker sleeve makes the average sailboat owner a great sailor. Without any help, the ATN Spinnaker Sleeve makes that very powerful and expensive sail disappear with a minimum of fuss and trauma. And the sail is ready to be hoisted again immediately, no more packing!

While it would seem that a spinnaker sleeve is a simple sailing tool, and that any one with a sewing machine could design and fabricate one, when dealing with large sails, the problems increase rapidly in complexity and cost. It is very plausible to get hurt or to inflict great injury to others, and to one's wallet, if the system used is inadequate. But there is no need to rub it in, especially at sea: it has to work and be reliable.