Thank you, point taken. Speaking of constraints, the concrete canoe competition held by the American Society of Civil Engineers shows that concrete is not really a constraint. Also, it would be interesting to see if you could repurpose Ikea furniture and make a boat.
I have always had a fascination with the concrete canoe competitions.
Looking at the 1st place PDF for the UNR team, and the admixture they have come up with; I have always wondered if AeroGel would be a suitable additive to the mixture in place of some of the other components.
AeroGel would additionally replace the glass aggregates mentioned in the PDF as well.
For example, they use polyvinyl fibers to add durability and flexibility to the mixture, as well as some other pre-stressing substance known as Komponent, which I am not familiar with.
I have always thought that it would be interesting to add powdered, or fibrous (if it exists) AeroGel to concrete for both insulating purposes (in the non-concrete-canoe use case) and weight reduction (canoe centric).
Additionally, once a fairly cheap, abundant source of carbon nanotube fibers could be procured - adding this to the mix as admixture to provide for strength and flexibility would be great. (I don't have access to either materials - so this is all speculative with respect to practicality.)
It is not that contrived of a constraint. My dad built two rowboats for my brother and I when we were young kids. Each one was built out of a single piece of plywood. Marine grade plywood is expensive, $40 a sheet I think, so the difference between one sheet and two sheets is significant.
http://www.jimluton.com/boats.php