The appropriate historical reference is not to shipping but rather to Silio Gisell, Worgle, and FDR's StampScript. Also, the difficulty with exchanges is simply that they could not do the demurrage accounting. Demurrage can be looked in a number of ways:

1. in Freicoin, the demurrage pays the miners.
2. the demurrage fee is a flat rate fee for unlimited transactions (current Bitcoin fees exceed 5%).
3. it was hoped that some of this money would apply to a kind of universal basic income too but no satisfactory system was ever developed.
4. it is supposed to make money 'deteriorate' like other commodities