Can anyone explain the difference between Severne Overdrives and Hyperglides for foiling, specifically in terms of range, stability and speed (for the same sail size)? I currently use the Overdrive M4, but I'm curious what a Hyperglide 4 or 5 could bring to the table.

I've switched back and forth between Mach1 8.6 m2 and Hyperglide2 8 m2 in 10-25 knot range over a couple of sessions. There's not much difference in terms of sail behavior for recreational riding, at least I haven't noticed it (using the same mast and boom). Perhaps a better rider would be able to push more out of the foil-specific sail.

The low end seems to be slightly better on the HG2 (it feels lighter and easier to pump), as well has control on top end due to being more high aspect ratio. So for foiling I prefer it, but all of the learning and falling I've been doing on the Mach1.

Would I splurge for brand new pricey HG4 or HG5 if I already had a race 4-cam sail that works perfectly fine on a foil? Definitely not, unless I'd be racing-competing. Probably if you'd create a blind test for me I wouldn't notice a huge difference between both, at least not one worth spending over a grand on a new sail.

Full slalom Mach 4's are built as a bit of a crossover sail that can do fin and a bit of foil slalom, so you wouldnt feel too much difference. Older slalom sails are twitchier and have the drive too far back compared to full foil sails in my experience. I much prefer the Severne HGO and NP Flight Evo sails for foiling.

Thx for the feedback. Due to the huge benefit of switching the sail between fin Iand foil, I'm now leaning towards either Overdrive or Mach 4/5 in size 7.8 for my next upgrade. Severne describe the Mach 5 to be designed for fin and foil, but no such description is given for the Overdrive. So, the question is now: how will the Overdrive M4 compare to the Mach 4/5 for foiling?

AndyPandy, for all intents and purposes the OD M4 has remained unchanged since the M2 (minor tweaks here and there in some sizes). On the other hand, the Machs have had significant revisions over the same time period, some of them targeted at having the sail perform well on both fin and foil.

As I understand things, the M5 7.0 and 7.8 have had substantial work toward that end, and if those are sizes in play, then the M5 would be the choice.

Select to expand quote

WindFlyer said..
AndyPandy, for all intents and purposes the OD M4 has remained unchanged since the M2 (minor tweaks here and there in some sizes). On the other hand, the Machs have had significant revisions over the same time period, some of them targeted at having the sail perform well on both fin and foil.

As I understand things, the M5 7.0 and 7.8 have had substantial work toward that end, and if those are sizes in play, then the M5 would be the choice.

Very useful info. Thx, M5 it will be

I did a blog on the overdrive for foiling - sailrepair.co.uk/severne-overdrive-m3/
But I am about to update the blog to the M4 overdrive. In the past I have found the overdrives have a large tuning range. The M4 seem to lean a bit more towards fin than foil. In the past you could go easy on the downhaul and the sail would still rotate well but the M4 needs a certain amount of downhaul to rotate well so you have a looser leach. So pumping the sail onto the foil is less effective.

I have noticed that when its gusty the gusts open up the leach and you loose ride height. So it is maybe harder to fly level in gusty conditions but having said that the sails do have a very good top end on the foil.

Talking of top end I recently had a 6.0 foil glide MK1 in for repair and out of interest I laid it on top of my 6.5 turbo - they were the same size! I think the 6.5 is quite true to size so it seems that to gain good bottom end on the foil glide Severne have simply made it a bit bigger. This got me thinking so I then laid my 6.5 turbo on top of the 7.0 overdrive M4 and while the 7.0 is a bit bigger I would say by 0.2m at the most.

Select to expand quote

Sailrepair said..
I did a blog on the overdrive for foiling - sailrepair.co.uk/severne-overdrive-m3/
But I am about to update the blog to the M4 overdrive. In the past I have found the overdrives have a large tuning range. The M4 seem to lean a bit more towards fin than foil. In the past you could go easy on the downhaul and the sail would still rotate well but the M4 needs a certain amount of downhaul to rotate well so you have a looser leach. So pumping the sail onto the foil is less effective.

I have noticed that when its gusty the gusts open up the leach and you loose ride height. So it is maybe harder to fly level in gusty conditions but having said that the sails do have a very good top end on the foil.

Talking of top end I recently had a 6.0 foil glide MK1 in for repair and out of interest I laid it on top of my 6.5 turbo - they were the same size! I think the 6.5 is quite true to size so it seems that to gain good bottom end on the foil glide Severne have simply made it a bit bigger. This got me thinking so I then laid my 6.5 turbo on top of the 7.0 overdrive M4 and while the 7.0 is a bit bigger I would say by 0.2m at the most.

Fantastic useful info, Sailrepair! I will test some different downhaul settings on my overdrive M4 7.0 to see how it impacts the foiling performance. And I'm really looking forward to your blog update with the M4!

The Foilglide sails work surprisingly well on fins also. They're not as sturdy of course but if 75% of your sailing is on foil anyway they're a good, simple option. The sizes are weird for sure - typically half a meter bigger than other brands in the same nominal size.

Select to expand quote

Awalkspoiled said..
The Foilglide sails work surprisingly well on fins also. They're not as sturdy of course but if 75% of your sailing is on foil anyway they're a good, simple option. The sizes are weird for sure - typically half a meter bigger than other brands in the same nominal size.

I've tried the Foilglide 2s (in 7 and 8) on foil and find them sweet in the low wind range, but too unstable in the upper wind range. As I sail in gusty conditions, I actually prefer the Overdrives over the Foilglides.