2 min read · Updated 19 May 2026
A spinnaker is the broad family of large, lightweight downwind sails, and a gennaker is a specific kind — an asymmetric spinnaker flown from the bow or a bowsprit, with no pole. So the two are not really rivals: a gennaker is a spinnaker, just the asymmetric variety that dominates modern racing. Understanding the distinction explains why a boat like the Melges 40 carries what it does in the downwind half of its sail wardrobe.
The symmetric spinnaker
The traditional spinnaker is symmetric — the same shape either side of its centreline — and is flown from a pole set against the mast, which holds the sail's windward corner out from the boat. The pole can be squared back as the boat turns downwind, so a symmetric spinnaker can be carried very deep, running almost dead downwind. The cost is complexity: setting, gybing and dropping a poled spinnaker is gear-heavy and demands well-drilled crew work.
For decades the symmetric spinnaker was the only downwind option, and it remains common on classic and many offshore boats.
The gennaker (asymmetric spinnaker)
A gennaker — the name blends genoa and spinnaker — is asymmetric, with one side (the luff) longer than the other, and is tacked to the bow or to a retractable bowsprit rather than flown from a pole. Without a pole it is far simpler and quicker to handle, and the bowsprit projects it clear of the bow and the mainsail's wind shadow.
Asymmetrics suit fast boats that do not run dead downwind but instead sail hotter, faster angles and gybe down the run to make their best velocity made good. They are set and dropped with the techniques in spinnaker hoists and drops, and they come in a range cut for different angles and wind strengths, from the A1 to the A4.
Which a boat uses
The choice follows the boat. A heavy displacement boat that runs deep may favour a symmetric spinnaker on a pole; a light, planing boat that sails fast angles favours an asymmetric on a sprit. The Melges 40 sits firmly in the second camp — it flies a large asymmetric gennaker of roughly 200 square metres from a retractable carbon bowsprit, exactly the modern set-up its planing performance calls for. More on the boat is on the boat page, and the wider inventory is mapped in the sails pillar.
Frequently asked questions
- What is the difference between a spinnaker and a gennaker?
- A spinnaker is the broad family of large downwind sails. The traditional symmetric spinnaker is flown from a pole set against the mast and is symmetrical about its centreline. A gennaker — short for genoa-spinnaker — is an asymmetric spinnaker tacked to the bow or a bowsprit, with one side longer than the other, and needs no pole. So a gennaker is a type of spinnaker, specifically the asymmetric kind.
- Is a gennaker the same as an asymmetric spinnaker?
- In practice, yes. Gennaker and asymmetric spinnaker are used interchangeably for a free-flying downwind sail tacked to the bow or a bowsprit, with an asymmetric cut. Some sailors reserve gennaker for a flatter, more reaching-oriented sail, but the terms broadly mean the same thing.
- Why do modern race boats use asymmetric spinnakers?
- Asymmetric spinnakers tacked to a bowsprit are simpler and faster to handle than a symmetric spinnaker on a pole, and they suit fast boats that sail hot downwind angles and gybe rather than running dead downwind. A boat like the Melges 40 plans downwind, so an asymmetric flown from a retractable bowsprit is the natural choice.
- Do you still need a pole for a gennaker?
- No. A gennaker is tacked to the bow or to a bowsprit and flown without a spinnaker pole, which is much of its appeal. A symmetric spinnaker, by contrast, needs a pole set off the mast to hold its windward corner out, adding gear and crew work.