We had great expectations to get out fishing Sunday.The fishing had been outstanding and the wind forcast was light enough for us to get out on my buddy's 18ft Lund.We have in the past, fished in bigger boats that we dock at a marina.But Jerry sold his 28ft Proline this past winter and only had the Lund to fish this season.He bought the Lund 3yrs ago,to mainly extend our season in the spring and fall,but I had only fished off it probably 3 times. We got to the portage river ramp and the first thing out of the truck is I tell Jerry to put the plug in the boat.We go behind the boat and gets the plug and places it in but says either too dirty or rubber worn to get a good seal.He then gets upset because he forgot to bring any towels or rags and can't clean the plug well.He then puts the plug in.I look at it and told him there are three holes coming out of back.I said,"did you put it in the correct hole because there are three holes there." He said he put it in correct hole and I assumed he knew what he was doing.I was wrong about that.See Jerry is now 78yrs old and has become more forgetfull as he gets older.I have become more vigilant in making sure everything gets done correctly and safely.Unfortunatlely I was not familiar with the Lund since have not been on it often and since 2017.We eventually launch the boat and headed down the river.Jerry starts bitching because he can't get his electronics to work.That is not unusual,he often has trouble with modern technology as many older people have too.I get out my trusty hand held gps and tell him I can navigate with my hand held.We pass the bridge and Fishermans Wharf commenting on the height of the water and how often they flood now.......we both look down and see water coming through the floorboards at our feet.I lift a lid and see the bottom filled with water.Jerry makes a U-turn and brings the boat up on plane and turns on the manual bilge pump.Water moves to the back of boat and I start throwing buckets of water out of the boat.Miraculously the water starts going down.The bilge is throwing water out faster than coming in.Not sure why the automatic bilge did not kick in first but might have been a godsend because might have made it onto the lake.I tell Jerry to take it back to ramp,but he says he is going to dock it at Coastal Marine which is on the way and where he stores in winter.I told him his boat will sink at the dock but he won't listen.We get to the marina and tie up on one of their docks and Jerry thinks he can put his hand down in the water and feel for the plug.I said bad idea with the engine still running.After several minutes he said think can make it back to ramp and get on trailer.We run it back to ramp and get it on the trailer with the engine running and bilge pumping.Pull the boat out and look at the back of the boat.Jerry had put the plug in the opening to the livewell.Water was pouring out the hole the plug should have been in.Lucky, that Jerry put in a new bilge when bought the Lund used and lucky we were not on the lake yet.I was not overly scared.I had my life jacket on and we were 40yds from land,but if we were out on the lake in that cold water.I told this story to my staff today and my first dental patient said today was the anniversary of her fathers' death.Said he died 5/6/01 on Lake Erie with two of his friends when they went out for the first time on the used boat he just bought.How ironic.Looks like we lucked out.Will never let that to happen again.