I took a non pilot buddy flying, and we stopped in at the local aerodrome/waterdrome. I watched a generously proportioned pilot finish fueling a 172 floatplane. He then boarded the two very normal sized passengers he had evidently flown in for the fuel stop. A 172 on floats is generally a two place plane, which struggles with full tanks at that. This pilot was two places all by himself. He pushed off, and started up.
I said to my buddy, "He's not going flying this attempt, he'll come back after five minutes and off load one pax, and even then struggle off the water.
A normal heavy takeoff in a 172 on floats would be 5 to 10 seconds to get onto the step, then maybe another 10 to 20 seconds to get off the water - so we'll give 30+ seconds on the water as normal. Embarrassing would be 45 seconds water run. I started my stop watch when I saw the nose come up and spray, with the application of power.
2:10 later, not even on the step, he gave up. He taxied back to the dock, and off loaded the husband. Thereafter he struggled off the water in a nearly 1:30 takeoff. I'm sure that he trashed the prop too....
I told the husband, who was now annoyingly stuck a 45 minute flight that I'd drop my buddy back, and return to assure that he did have a flight back to where he came from. By the time I got back, he'd had a call from his wife, who made it safely, saying that the pilot was returning for him.
It turns out that the couple had bid the 1.5 hour sight seeing flight at a charity auction for more than $3000! I suppresed the desire to laugh out loud - I hope it was a good charity! He was duly pick up, and struggled off the water.
I mentioned to the owner of the 172, whom I knew (not the pilot) that an inspection of the prop would be prudent. The response: "He hasn't wrecked another one!?!".
If in doubt, fly light, 'till you're really sure....