Alcohol induced self-confidence

(n.) An alcoholic beverage had before an unpleasant task. The fact that britains' second empire and the Netherlands' first rose at the same time caused a great deal of tension between the two nations (though never real animosity like there was with France) and when they joined in temporary naval alliances they noted that dutch sailors took thier alcohol allowance just before battle, whereas the Royal Navymen drunk throughout the day.

drinking to have confidance

liquor, false courage from drinking liquor(this use, like many derogatory uses of dutch, comes from a time when England was at war with Holland. However, dutch also means German, which can be confusing)