A 3-D printed yacht would be a dream come true for many.

This would be a huge benefit, in places where a tornado, hurricane, or other man made disaster hit. People could have temporary housing set up in no time. With them using recycle materials, I'm assuming after the need was over, they could bulldoze them down, and use the material again?

I think one could also make a 3-D printed house boat? perhaps a pontoon house boat?
I think that is neat. I think it could help people who want to live in a smaller house. There is a trend among some to live small, small houses to tiny houses.

Re-using building debris is a huge thing. Imagine the avoided impact and energy spent to gather, transport and dump what conventionally would be deemed as 'waste' somewhere unflatteringly, and use it for something constructive.

I think 3D printed houses will become the norm, but that will be several decades. This is just the beginning. These "houses" are small and ugly with no plumbing or electrical or HVAC, I would never live in one. But for 3rd world countries it's certainly better then what they are living in now.

Still pre-fabbed in a central factory? Not quite roll-up-and-print-it 3D house manufacturing then. For disaster victims, however, a good idea.

Surely the plumbing and wiring can be easily added within a second inner lining to the main structure? Can be pre-fab'd in large sheets and simply joined up on site. Similar to the plush German 'huffhaus' method.

This is great!
I'm in New Zealand and this kind of thing would be *very* useful down in Christchurch as they rebuild after the 2011 quakes. They are making progress down there but it is *slow*.
The Japanese would have got a few truckloads of these 3d printers after a quake and would have a city pretty much rebuilt in a year or so. A pity that Christchurch has been so slow with its rebuild.
I believe that the councils of every city in NZ should be required to put aside "x" thousand acres of land outside their towns for emergency housing. (This land could be used for other purposes e.g. farming - in the meantime but would be used for housing in a major emergency). If this were done (and if a few 3d printers were bought) then a place like Christchurch would be rebuilt in no time! *So what* if the hastily-built structures had a slight lean on them or whatever? They would still be functional. Simple, basic-but-effective housing for people to stay in while they got their lives back together.

I'm not sure about that 2nd paragraph. No doubt China is building at an amazing rate - but I was in Fuzhou not long ago and there are hundreds (if not thousands) of new high-rise towers of flats that are completely empty of residents. It seems they keep building them but for some reason (price, perhaps?) they aren't being occupied. It's almost creepy, passing these ghost developments one after the other along the highway like the backdrop of some distopian movie. Whatever the reason, this not capitalism as we (westerners) know it, it's something else - perhaps something unique to modern China. No banks in the USA, Europe, Singapore, Hong Kong, or Taiwan would (or would be able to) float the loans for such vast tracts of housing that is built up and then just sits there, empty.

Of course we forget we actually need the 3D printer, tons of concrete and glass, trucks to deliver them, oh and a crane that can lift them, along with an army of day laborers to put them together...all without plumbing and electricity....yup! Looks like another winner from China!