LOL. Where did you get this picture from? The starboard stays look like there is no tension at all and the vang is a cantenary with no tension, even though the mainsail is pulled almost all the way out. Who's watching the the mainsheet, causr the skippers not.OK, so this is for everyone but Dave. ;^)
When about boat (in particular a flat bottomed boat like the 170) is sitting flat on the water is has max wetted surface area, and max parasitic drag. A large bottom area drawing 1-2 inches of water. But when a boat starts to heel, now the reserve buoyancy in the now-submerged bilge/hull provides the required displacement with more draft (4-6) inches, but in a much smaller area as the same number of square feet are providing buoyancy. See this pic of a 170, the entire port side of the bottom is out of the water, the buoyancy for displacement being provided by a much wetted smaller area on starboard. Other factors might effect the particular boats optimal ability, but this point is a universal truth.
View attachment 141348
Looks like this.
View attachment 141349
Theres 4 people on the port and its still heeled. The wife is holding on to the youngest child like a human shield.
The water looks calm though for heel. Are they starting a tack to port?