In the 16thC, most trade was transported by sea. As ships were made of wood, the hulls tended to rot and often a ship would disappear on route, simply because its bottom had fallen out. This, plus all the other hazards of early shipping, meant that you could easily lose your livelihood. The main money 'brokers' at that time were the Dutch. If you wanted a loan, thats who you went to. Anyway, they came up with this wizard wheeze; insurance. They would help finance the shipping operation, for a large share of the profits, but would reimburse you some money if the ship was lost. This early form of insurance was known as 'Going Dutch'. Someone then discovered that you could almost prevent the rotting of hulls, caused by the main culprit, the teredo worm, simply by cladding the hull in copper.(They just couldn't chew through metal!). Such a ship was of course 'copper bottomed'. Any shipowner who had this done had made a 'copper bottomed investment'. So by the end of the 16thC, the best thing you could do was 'Go Dutch with a copper bottomed investment'.