The small LASH barges could be combined onto a big ship for efficient travel over long distances.   The idea of combining different small boats into one big one could be of interest to seastead folks.  Instead of barges with cargo imagine barges with houses built on them.

One design, a "FLASH Ship",  was to sink down in the water a bit so the barges could float into position:

http://kemahpartyboat.com/

In 1969 this type of barge seemed like a good idea:

   http://www.time.com/time/magazine/article/0,9171,901430,00.html

In 1971 it still looked good:

http://www.time.com/time/magazine/article/0,9171,904874,00.html

Except that the US longshormen got a promise to only load and unload barges at the port, which kills the main advantage.

In 2006 there is an article with a picture of a ship loaded in Holland with the barges:

http://shipoftheday.blogspot.com/2006/11/rhine-forest-spruce.html

Wiki page that seems to be translated from German:

http://en.wikipedia.org/wiki/Lighter_Aboard_Ship

 Some ships used crains to lift the barges but some had locks built into them:

http://www.globalsecurity.org/military/systems/ship/barge-carrier.htm