I made a miniature hydroplane, 6ft x 4ft with 7" sides, in the lounge room around 1968. Do a Google or YouTube search for Mini Max Hydroplane to see what it was. Couldn't get it out the door and up the passage. Had to remove the window and take it out that way. It didn't finish there. Took it out for its first lake run and encountered another boat's wake and, with no experience, didn't know how to cross its wake. I crossed it at 90 degrees. Felt like a submarine for a few seconds as it bit into the wake and ploughed under water. It was unsinkable though, a fact that I used to terrify someone later, and, thankfully, came out again.
The last "wow" moment was when I took it out for the first time after connecting a steering wheel to the outboard motor some months later. I headed straight out from the shore and, when I made my first turn, discovered that the steering had been connected arse-a-pookus - when I turned to the left, It went to the right. Embarrassing. Someone in a speedboat tried to swamp me by making a sharp turn and spraying some of his wake into my boat. Thankful for that unsinkability again.
All part of the DIY fun that you don't get with buying. Funny how some things trigger memories.