Sci-fi topic: Shall we one day be growing our boats?

Can't see why... It's all a matter of materials and careful structural engineering, as demonstrated by F1 cars.

 

It won't be the most practical car in the world, but I just love these guys' fantasy.

 

I think 3D printing will be huge in the future construction of ANYTHING. All you need is a printer big enough, or an object designed to be assembled from printed parts.

Some of the materials they are using for 3D ink:
Chocolate
Bio-Ink
Bone Material
Hot Glue
Full Color Sandstone
Glass
Medication
Skin
"Rubber"

Yes, they are printing "bones" to use in reconstruction of the human body. They use the basic building blocks of bone material as the "ink", print the bone, insert into the human body in place of the bad bone, and new bone material grows around the printed bone, while the body slowly reabsorbs the printed bone, and, Voila'!, you have a brand new bone.

They are also working on printing full organs, such as kidneys, that the body likely wouldn't reject.

Skin printing is huge for burn victims.

There is also a pen that you can use to draw your design in 3D in real-time. The pen dispenses ink that solidifies almost immediately. I cannot find the link to it at the moment, but I believe it is a kickstarter project that went viral.

 

They are ready to print houses.

http://www.gizmag.com/kamermaker-3d-printed-house/26752/