floor drains..Two questions

[caper]

I had '75 20SF with a 2003 Johnson 175 2 stroke at 385 lbs. - batteries & oil tank under the console and the 47 gallon aluminum fuel tank pushed forward as far as it would go. Kept the boat on moorings or wet slipped and never had an issue with the through the floor drains. I did always keep the in the floor livewell drain plugged when I left the boat for a few days. My drains were about 1" above water when the boat was at rest with a full tank.