I think supa is gunning for silliest question. But he failed here. This question is actually kind of interesting.
Yeah, I wasn't sure if this one was serious or not since it was posted along side "my bro foil"
but I thought it was kind of an interesting question, haha
True - what a stupid way to ruin a forum for others, especially as most on this forum dont have english as their native language
But seems most has learned to ignore these posts..
To the topic - of course the salt water will make the foil lift earlier.
Just like it will lift ANY board earlier.
Salinity varies a lot though.
Around here in our open sea to the east, it is only 1% giving an increased density compared to freshwater of 0.8%
At the westcoast open sea, and most open coastlines, salinity is 3.3% giving a density increase around 2.6% just like Dave writes
In the mediterranean salinity can go above 4% easily though.
And as lift is squared with windspeed, you need 1,6% less speed to get the same lift, if in 3.3% saltwater compared to freshwater, because of the 2.6% density difference (just like Dave calculates).
This does not go for foils only though - but ALL sailing crafts, twintips to foils and everything in between.