It is with great trepidation I disagree with you, given your reputation as
the fastest P19 sailor on the planet, but I wanted to make a case for the
3:1 (unbalanced) mainsheet equipped on many potters.
I agree its somewhat unbalanced, but I disagree with your assertion that you
shouldn't touch the mainsheet during a tack. At least if you're going for
speed, I trim up hard as I'm coming through the wind to give the boat an
extra shove, then ease the sheet way once I'm on the other side to kick the
boat into low gear to accelerate it out of the tack. I don't get back to my
previous sheeting until the boat is back up to speed.
So, my overall point is that you often want to re-trim during/after a tack
anyways, so the balanced nature of the 4:1 isn't necessarily a huge
advantage, at least when going for speed. for simple pottering, i can see
how the simplicity of that approach might be nice.
This might be a light-air thing, though. You bay sailors just don't know how
good you have it :)
I suppose in your heavy air the 4:1 purchase is welcome. For my
predominantly light-air sailing the 3:1 setup uses a lot less line (read: a
lot less clutter) and faster trimming and easing.
For those who do want a 4:1 arrangement, I also suggest instead of a double
block, use two single blocks if using padeyes to attach them to the boom.
This will spread out the load, causing less severe load on any one padeye.
I've had one rip out. on my 3:1 I fasten the line on one padeye and hang the
block off another.