They're made to test a new version of a sail, it will have the mast and boom measurements on it and a Version Number, prob small in pen. They could be close to production or nothing like it, this would be why the measurement are different.

Every sail goes through the same process, a lot are steps backward and some are almost right, the best ones are usually kept and sailed alot and that version goes into the next stage, then production.

So every time you go and buy a new sail remember, this is the final product after a sail has been designed, tested, tweeked, redesigned, tested, tweeked, scrutinized, tested again, over and over and over, then given the OK.

Every time a Proto is made the sail company puts there hand into the cash draw and hands over a stack of cash to get it made, and Prototyping anything isn't cheap, most people wouldn't pay this price for something that may or may not work, sails usually take a minimum of 7 to 8 hours to be made and that's a wave sail.

There is no such machine with a magic button you push and a shinny new sail pops out the end in a few minutes, every sail is made the same way, by hand..

Thanks PC. Just noticed the rigging details are in small texta writing on the sail in photo and they do match the website details for this model. (Unlike the other sail that is a v.2)

"PP" as in pre-production. Meaning this proto was made at the factory in the same way as the real production sails are (hence it has some graphics on it) , rather than hand made at the loft by the designer (Ben).