User:Vincecate/Tension circle marina

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The idea is to use a tension circle to make a marina. This could be with boats backing up to the inside wall and attaching. Maybe we need a custom built boat for this. Or we could have slips inside that boats attached to like a normal marina. These would have to be really strong slips though.


The opening should have rolling boat bumpers on the inside. The opening should be a bit bigger. And the opening has some way of closing. Also, the marina should probably be a bit bigger for this size boat. And instead of the boat pictured, it should be more like a Hunter 49 but with solar panels instead of a sail.


Custom Boat

A boat designed for this floating marina could have something to attach to the inside of the marina on the back of the boat. The attachment and boat could be such that the boat could hinge up and down some on the attachment without damage to the boat or marina. So water going up and down some inside the marina could make boats tip some relative to the marina wall but still not hit each other. Mostly the marina should be going up and down with the water inside the marina, so boats should not tip too much relative to the marina. And a 200+ foot wide marina should have a reasonably gentle motion most of the time.

Might even make it so that two boats could attach together as they were leaving the marina so that 2 boats of 50 foot each acted like a 100 foot boat for a trip together.


  • Material issues - concrete, foam inside wall. Since it does not go far below the water foam and concrete should be ok. With foam cracks in the concrete will not be fatal. The wall could be somewhat like the one at the bottom of this page.
  • Tension members could be plastic rope or steel cable

Requirements Analysis

  • Safety
    • It is very wide compared to boats and so should be very stable
    • Wall is filled with foam so essentially unsinkable
    • No active ballast controls so no chance of that going wrong
    • Not clear how we make boats inside safe during hurricanes
  • Comfort
    • Should have a gentle motion on normal days but significant response to large waves.
  • Cost
    • Depends on size.
  • Pretty
    • Looks nice.
  • Modular
    • May be able to scale by adding wall sections. Can make multiple marinas. Different boats can come and go. In really large marinas wall sections could be living space and they might also come and go.
  • Cargo
    • Very easy for a boat to come into the marina and transfer cargo to other boats.

  • Free Floating
    • Yes
  • Scalable
    • Probably reasonable to make marinas like this from 200 foot diameter to 1,000 foot diameter.
  • Standards
  • Mobile
    • If the tension members are removed from wall it can go through the water like a snake so moving can be very economical.
  • Draft
    • Very shallow draft.

Videos of 9-foot model tests

<youtube v="oLKEpt2wAS0" /> Initial launch.

<youtube v="Qc8ok78phok" /> Small boat inside and out.

<youtube v="HxUszZyNgXs" /> Real boat in background.

<youtube v="JHWFS2fcX9E" /> In transport mode.