Conex dumbbell

This basic idea was purposed in the structure designs book, with supplementals added here.

A single-spar column consisting of a modified CONEX shipping container. With the possible addition of a top deck, and/or expanded buoyancy at the bottom of the spar. The full google sketchup 7 model can be downloaded here

Google Sketchup model of a 40' CONEX Sea Spar

   * Safety
         o Probably only safe in fair to moderate weather as corrugated steel is not meant for high pressure.
   * Comfort
         o Cramped living conditions
         o Few amenities
         o While free-floating, the small size and few moving parts should mean that the low power draw nessisary for daily living could be sustained entirely 

from wind/solar/wave energy sources, although a desil generator remains for emergencies or high power consumtion periods.

   * Cost - cheep-ish, probably <$25,000
   * Pretty - Ugly.
   * Modular
         o CONEX units are designed to lock together during transit.  Spars made from them should be able to connect with relative ease and security 

as long as the units do not sport any top decks or other protuberances along the formerly 'top' or 'bottom' sides. However, units could only take advantage of this design feature to connect in a single line; not to make larger square areas.

         o Units with uniform decks may be connected also, though with somewhat less ease, and more flexible geometry.          
   * Cargo - As each unit is for only one (or a few) individuals the load requirements are much smaller then with larger designs.  By devoting one entire 

floor to cargo storage, and a second, smaller floor devoted to liquid tank storage, there should be enough room to supply the spar for several months worth of provisions

   * Free Floating - Yes
   * Scalable - CONEX cans are available in several sizes from 20' to 56'.  Multiple units could be welded alongside each other to increase the footprint from 

8' x 8.5' with no practical limit except cost on the number of units joined together.

   * Standards
   * Mobile - Yes.  Purpultion could come from sails 
   * Draft - Would be difficult to draft lower then ~25', but could run deeper depending on the spar configuration.