Have you had a chance to make/try the DP cap shield yet? I'm getting backdrafts too often in 15+ winds and the stove is useless in 20+.
I have 22" of straight pipe, then another 16" in a gentle curve inside the boat. I have a 22" extension piece that I'll use when at the dock capped off with the DP cap.
I've tried to use foil to cover the windward side of the cap, but that is of little benifit. I'm at a crossroads of either trying the H style cap, or making a DP cap shield.
your, or anyone's experiance would be nice. I can add another 22" pipe above deck if needed too.