Amoni (my 7 year old) and I built a couple models. We glued together 3 or 4 layers of 2 inch thick styrofoam with Gorilla Glue.
Then carved this into the shape we wanted with hot wire.
Then sanded. Then pained on StyroSpray 1000 which gives it a nice tough finish. Used a 1/8th inch plywood in the center of the floats and a piece glued under corners with metal brackets connecting these together. I really like making models this way.
Ethan (now a teenager at 13) and I tested these models.
These models are 4 feet long and 2 feet wide. They are 1:16 scale, so full sized would be 32 feet by 64 feet. Loaded this model is about 10 lbs, so full scale loaded would be about 16*16*16*10 = 40,960 lbs. You could clearly do other sizes.
We are testing where the biggest waves are about 1 foot. At 1:16 scale that means we are simulating 16 foot waves. In the Caribbean we only see waves like that during hurricanes. Normal waves seems more like 3 to 8 foot.
The video needs to be slowed down by the square root of the scaling factor to show you what it would look like at full scale. I think my video is slowed by a factor of 4, which is correct for a factor of 16 scaling.
I would really like to be able to connect several of these together to make a train in the water. It would let you travel in larger groups. You would only need one captain at a time. You could trade things between the boats. Attaching the boats together will also make them more stable. And boats following behind will go over a bit smoother water as they are in the wake of the boat in front of them.
The video below is looking at how these two different designs are moving relative to each other in hurricane conditions. At least at first we probably want to connect in harbors or at least in much calmer weather.
Note also that the 3 float version on the right rolls much more than the 4 float version on the left. I like the 4 float version much better.
The quadmaran has a very smooth ride for waves this big. In small waves it will be much more stable. The shape of the floats (two sections of a sphere glued together) makes the waves just go around it and not splash. This boat will not get spray on it like most.
When the models are connected together rubber bands on the sides keep them lined up straight in video below. This video was not from my slow motion camera but just slowed down for scaling effect, so it is not so smooth. In the full scale there would be bother computer control to keep them lined up and some stretchy rope as backup. Because they are much more stable than a normal boat I think connecting them together will be possible.
In the full scale version the weight of the batteries would be placed in the corners, making it a bit more stable than the model is. Also, the part connecting the center to the floats would probably be open to minimize wind resistance.
The hope is that a normal boat is affordable by the upper middle class American. If someone had more money they could get more than one and link them up for more space.
If you have a group of boats chained together it would be possible to split up and have some visit an island while some stayed in international waters. This way weapons could be kept in international waters.
Next I would like to build models at half scale using aluminum truss sections. Some of the truss sections would be inside the floats, with foam pored in a mold around them and then styrospray and fiberglass/apoxy on the outside. First I would build one and if that works then build a second to test connecting together. These would be plenty big enough to day cruise around on. Could put on the solar and electric.
Assuming the half scale tests work out well, the finals step would be to build a full scale with professional aluminum boat designers and builders.