I'm getting a new quiver of sails and looking for advice on sail sizes with the advances in 4 batten sails and the amount of power they are producing for m2 size as i see makers are saying that a new 3.9m is equal to a 4.2 etc etc.

Traditionally i have always had sails 4.2m, 4.7, 5.3 and 5.8 for my 75kg and sailing in WA. I am replacing North ICE sails. Looking at NP Fly2, North Hero or Severne Swats. With the apparent boost in power per m2 do i need to change my sail sizing and spacing. I prefer to sail powered or underpowered rather than overpowered and do like to get away with the smallest sail possible

What is anyone experience/recommendations. I sail RRD twins but will be getting a thruster soon.

Last year I upgraded to the 4 batten ezzy panther elites from the original 5 batten panthers. Can't say I felt any difference in power (maybe slightly less if anything) but the new sails did feel lighter and easier to throw around whilst retaining similar stability and wind range. I'm also 75kg and my sizes are 5.3, 4.5 & 3.7 however I live in Geraldton. I did have a 5.8 but I sold it as I hardly used it since I made the move north 2 years ago

Some 4 batten sails were still made as DTL sails which have less power...a 4 batten freestyle sail should produce more power for sure. Or even a 3 batten sail from XO (Fusion is the model), is a freestyle/wave sail and is really powerful, meanwhile their model Skull is a 4 batten sail which is very flat and not so powerful. I'd say that firstly you need to see what's the sial's purpose then how many battens it has.

Agreed, # of battens won't tell you anything about the sail. HSM's 5 batten Firelight is very powerful, can choose one size smaller than normal. Their 4 batten QU4D is normal power, take the same size as normal. Their 3 batten KS3 is again very powerful, take one size smaller than normal.

Best to email the sail maker and ask. Since I don't think North or Neil Pryde sailmakers are easily accessible you can only buy Severne.

i got a 4.2 hero 2013. and 4.7 ice 2011.
very little difference, would say it feel like a 4.5m.

so guess it just down to what the sails has been designed as i.e power wave or control sail as per normal. cheers yaya for info there as I'll probably being getting Norths as I get alot of seasons out of my current North. Planning to live between geraldton and exmouth for season so decided to get 3.7m to 5.7m which should have me out in most conditions. Going for Hero 3.7 to 5m then IDs upwards.