In many family yachts if a person falls overboard there is nearly a 50% chance
it results in death.  It can take a long time to turn a sailboat and get back
to the spot where the person was and it can be hard to find them in the waves.

The seastead is far more stable than a normal family yacht, so the chance of
falling over is greatly reduced.

The seastead will be going on the order of 1 MPH and most people can swim 
faster than this for a short period.  There will be ladders on each leg, so 
someone just needs to swim to the nearest leg and they should be ok.

To make it even safer we will drag a float on a line like 200 feet behind
the seastead.  This float can have a solar light and an alarm button (also solar
powered) to alert the crew on-board.  And straps so the person in the water 
can be secured to the float.  Then if someone falls in they just have to
get over to the line before it passes all, which is even easier than catching
up to the seastead.

Once strapped into the float the person could pull on the rope to get back
to the seastead or wait for help.

The alarm could even cause the seastead to stop.

Man overboard should be far less dangerous for this seastead than a
typical family yacht.

Please do a clean write up the above and expand the ideas.  

Also try to locate examples of each of these and the approximate cost:
   0) Rope that floats, is highly visible, and thick enough to be easy for a person to hold onto.
      Also want something on the both ends so it does not chafe against either the seastead or the float.
   1) Float that could be trailed behind seastead and easy for swimmer to get onto.
      Seems like there should be something more modern than just a ring.
      Something large enough that a solar light and alarm can attach to.
      Something strong enough to last months and maybe of being towed in the Caribbean.
      Would a dinghy with a dinghy ladder be a good float?
      Maybe a small Rotomolded Polyethylene Hard Dinghy that would last a long time?
      There are "rescue sleds" towed by Jet Skis that might work.
      There are "rescue sleds" used by white water rafters that might work.
      Rescue sleds are designed to be easy to slide onto from the back, which is good.
      Are there rescue sleds that aer rotomolded and foam filled?
      The  Bic Sportyak 213 dinghy is small and has lower edges so boarding should be ok even without a ladder.  
                It is rotomolded and filled with foam so it should last well.
   2) Solar powered marine light for the float.
   3) Solar powered marine alarm button that can wirelessly send a message to the seastead.