And I had just converted my system to direct to storage tank. With a Whale pump just over the tank, to the overboard, I leave the through hull closed and the handle off.

From an inspection pov, this is all pretty silly and basically not enforcible. Only in lakes where they inspect for no discharge can they hand out fines left and right(no nonsense regs on ties, Yvalves, etc). I keep a handle in the locker above the tank and can open the overboard at any time, or close it(I would have had plenty of time as the Cutter approached). You might have a problem if you can't keep the handle off the seacock, unless it's easy/fast to remove.

My set up was well received. Reminds me, I still need new flares though,....