Randleman mentioned mine above...here's what I did from outside...fittings and hose all 1 1/2" ...used plastic for cost reduction figuring if I ever recore this particular hull, they'll be upgraded to SS
Here's the hose connecting the two fittings...Pete's has the backflow valves I would like to put in here someday...
And here's the interior fitting Randleman mentioned...I REELY like these as the opening is right down on the floor deck for water drainage...nothing to dam the flow...they also allow better drainage over the original in-floor drains because those had 90* elbows just under the floor which could lead to a clog, PLUS water going through from floor level actually had to go back UP to drain out of the boat...these allow all downward flow
Here's the thru hull w/200 Merc and batteries moved forward...but while fishing, if two guys at back of boat this did allow water in, so that's why it'll eventually get back flows like Pete's
Personally I like 'em out the sides instead of thru transom...good luck and keep the great posts comin"!!