Okay, what I ment to say was that for me, at sea with on-shore or cross-onshore winds above +30kts, catsailing is almost impossible.
But on inshore water (or off-shore wind at sea) there should be possibilities to go further then 30 kts.

Because, comparing to windsurf sailing, the windspan of a catsail is much larger. I mean, I can use my one catsail from 10 kts to 30 kts.
For that same range there are at least 4 or 5 surfsails.

So, you possibly could use in catsailing just one smaller sail (like in the old days of windsurfing with a 4.7). And that sail you hoist up on the beach when needed. And it has of course the right luffcurve for your mast. Simply a sailchange onshore.

On a windy day you have this extra smaller sail with you in the car or even on your tramp. And we catsailors can always go ashore very easy!

Writing this down, I realise that I could do this for myself also. A smaller sail which I will hoist at say +25 kts., or even less if the wind is going to increase.

Thanks guys