Revised by BoatUS editors in April 2012
"Troublesome" is a common impression of spinnakers, but it needn't be like that. With a bit of practice, spinnaker handling is easier than you might think, and the advantages of boatspeed and balance downwind will make learning worthwhile. Advances in technology also help less experienced crews to tame the sail. A lot depends on what equipment your boat already has. Does it have an extra halyard, winches and topping lift?
Cruising spinnakers, also known as "gennakers" are popular on non-racing boats. These are cut similar to spinnakers but do not require a pole and can be used with wind on the beam as well as downwind.
Almost all spinnakers require a spinnaker pole. Its purpose is to hold the windward corner of the spinnaker out away from the boat in clear air. Its length will normally be that of your boat's "J" dimension - the distance between the mast and the jib tack. The pole thickness depends on the length and power of your boat, following manufacturer’s recommendations.
Like genoas, spinnakers need a pair of sheets. On larger boats, two afterguys are often required for "dip-pole" jibes. Snap shackles are great for attachment because they allow for easy adjustments. Dinghies and smaller boats can use a single set of sheets and sister-clips for quick attachment. Low-stretch line is recommended for obvious reasons. Many racers will use as light a line as possible, not only to save overall weight, but also to keep the spinnaker flying in light air. Choose carefully though, otherwise your spinnaker can disappear skywards should your sheets let go! You may want to have two sets available - one light and one heavy.
You need the ability to move the inboard end of your pole up and down as the conditions dictate. On smaller boats, a mast car with pin stops is enough. For larger boats, which place more pressure on the pole, adjustment lines are required, as well as a pole car with uphaul and downhaul bails.