Why lateen sails on the mizzenmast?

[Daniel]

Throughout the 17th and early 18th centuries, a huge number of the vessels I see are lateen-rigged on the mizzenmast. Long after square sails were routine on all other masts, lateen sails stayed on the mizzenmast. Not only were plain barques very popular, but even full-rigged ships with square mizzen topsails or mizzen topgallant sails still very often had a lateen mizzen sail (or "crossjack") below. Why was this such a popular design?

On a barque, I can see some logic to having a fore-and-aft-sail on the mizzen, because it would be less prone to steal the mainsail's wind when running before the wind. But the same logic would seemingly apply on a full-rigged ship to the mizzen topsail stealing the main topsail's wind, and yet most shipbuilders happily rigged square sails on the mizzen topmast and topgallant mast. And even if a fore-and-aft sail is less likely to steal the mainsail's wind, why specifically a lateen sail, rather than a gaff-rigged and/or boom-rigged sail? Isn't changing tacks with a lateen sail extremely difficult?

[Fox]

The reason for the fore-and-aft rigged sail on the mizzen is to aid with steering. Tacking is not too difficult, on one tack the sail is backed against the mast.

The reason for lateen sail over gaff is principaly one of evolution. The gaff sail wasn't really developed until the mid-17thCish, and although it quickly became popular on smaller vessels it took several decades for it to become popular on larger ships. Once it did take hold the change came quite quickly.

[Daniel]

OK, thanks, Foxe. Why was the fore-and-aft sail used for steering? Is there a site that explains the use of lateen sails for steering?

[the Royaliste]

Simple sailin' dynamics, mate....Mizzen sails, i.e. lateen, spanker, or whatever, they appy pressure in the general vicinity of the rudder. Since they are fore and aft, they are effectively an 'opposite' plane to the rudder itself. Sheet hard, and the rudder receives the pressure. Ease off the sheets, and the 'weather helm' disappears and the rudder becomes more effective...

[JoshuaRed]

Think of it as a bigass extra rudder.

[Coastie04]

Take a look at this simulator if you want to play around with this aspect. HMS Surprise I've been playing around with this simulator for years and have made schooners, barques, brigs, etc. with it by adjusting the sail characteristics. It's really a neat simulation that lets you play around with trimming the sails and how they work together to make the ship go. I'm sure any tall ship sailor will appreciate the accuracy of it. There are many forces that act upon the boat to make it handle differently including, but not limited to, the wind, heel angle, rudder, and trim of the sails.

Enjoy

Coastie