For the past 3 or 4 years students have been helping to build a wooden rowing boat. It's taken so long because they only work sporadically, during project weeks and when the expert boat builder (the one who is really building it) has time to visit. Its all part of the Creating A Small boat programme. The boat in the picture is similar but no where near as fine as the one in question which is housed in the turf roofed boathouse in the background. The green building is where the physics lab is by the way. The other day I went down to  the college to check on a few things and was press ganged into helping to lift the boat to the other side of the boat house, well it looked heavy and I was a bit sceptical as to whether the four of us would lift it, then four more arrived, and another two. So here comes the physics, when we started lifting I was expecting it to be heavy, actually it was heavy, so I exerted a big force. As I got tired I relaxed a bit and eventually found that I could just pretend to lift it and no one seemed to notice. What if everyone had done the same thing? Afterwards I asked if everyone had found it surprisingly light and they had. 10 people lifting a 200kg boat so each is holding 20kg, I decide to take a rest and everyone is left holding 2.2kg extra. Its actually a bit more complicated as it depends on how the weight is distributed and the angle of the boat.Maybe its also something to do with perception, expecting the biat to be really heavy so anything less seems light.