My 20SF with a saltwater 150 ETEC (433 lbs) I use plugs in my drains all the time. If I have to wash down some blood or fish slime, I bucket it in, pull the drains, and keep the boat in motion. Flows right out - them I plug them back up. Honestly, I have gone many all day trips and never pulled them. If I don't have them in, I too will have an inch or so of seawater on the aft deck.