Although i had seen DIY ergometers before, i had completely forgoten this option. In a rowing club i was following many years ago we had one but not of this type and of course we prefered to use the Concept II. In a neighbour kayak club they had only ergometers of such type-DYI with bicycle wheels.
Wanted to bump this with a quick video of a new kind of "ski" machine setup. I actually quickly found a link to another youtube video (the 2nd one) where a guy threw together a DIY version that uses the same very basic but nice setup of the bungie cords with the bicycle gear/chain setup that allows for smooth pulls and returns on the DIY rowing machine. What I really like about this kind of machine (assuming it actually delivers a decent workout) is how TINY the footprint is in terms of floorspace. I could squeeze one of these in just about ANYWHERE. Rant over. :P Hope you guys had a good thanksgiving.