User:Vincecate/Models

Idea is to use about the same amount of pipe in each model so they are sort of cost comparable and then test them all in the waves at the same time. Expect to have waterproof camera around July 10th.

I am going to assume migration makes 25 foot waves the largest we have to deal with because with a 1:25 scale model that makes for a nice round 1 foot wave.

A 75 meter pipe spar is about 250 feet, so scaled down we would use 10 feet of pipe.

If I use 2 inch diameter pipe in models that is like 50 inches in the full scale version.

PVC models planned

• Tension Circle House
• Versa Buoy - maybe a triangle - 3 pieces of 3.3 feet each - simple balsa wood platform on top
• Pipe Spar - 10 feet of 2 inch pipe
• fat-short pipe spar - using 3.5 feet of 4 inch pipe instead of 10 feet of 2 inch pipe other models get
• semisubmersible - can have square of pipes underwater and legs sticking up
• semisubmersible with hanging ballast - same model as above but with 4 strings to single ballast in middle
• catamaran - 10 feet of 2 inch pipe cut and with fittings to make catamaran
• raft made by lashing pipes together - 5 pieces with 2 cross pieces underwater (120-(2*12)/5= ~19 inches for 5 pieces
• beach ball half full of water with some sand in the bottom - kind of the givens life raft design.

Video

I will put a glass of water on the model that will start the video full. During the video the motion and splashing of water, as well as how much is left at the end of the video, will give help give some idea of how stable it would feel to someone standing on the structure.

I will shoot video from the side with a horizon/beach/island in the background for a stable reference point.

I will also shoot video with the camera mounted on the structure. Slowed down the view of the glass of water, waves, and horizon should be interesting.

Still shots

Will take still shots of each model out of the water, in the water, and view from under water.

Force for Scale model speed testing

The force on a scale model should scale with the mass, which is with the cube of the scaling factor. So for a 1/25th scale model, the force should be 1/15625. So we have:

  8 ton kite -->  1 lb
  16 ton kite --> 2 lbs
  32 ton kite --> 4 lbs

Weights from a weight set or a gallon jug filled with the right amount of water could be a good weight. With a known weight being pulled down by gravity you can provide the same force to the model by connecting a rope between the model and the weight over a pulley. Just have to keep pulling the pulley forward at the right speed so that the weight stays between the pulley and the ground or water. With my Hobie pedal powered kayak I think this will be easy enough.

With speed results from this we can see how fast such a kite could pull a full sized seastead. This will tell us if the migration idea is plausible.

Problems

• normal sched-40 fittings are heavy (elbows, Ts, etc) - try to find lighter ones
• not clear 10 feet of pipe can make some of the designs clear 1 foot waves (or even 6 inches)
• what to use for ballast - washers, cement, water