What is this?  Specifically in the context of BearTrap and BoatAnchor?

Google is your friend. Type

  define: "white elephant"

and google tells you

	Something that is so costly to operate that the potential for profit is quite low:	http://www.yourinvestmentclub.com/dictionary.htm

	unwanted object, especially something that was expensive to acquire:	http://www.ivey.uwo.ca/intl_students/dictionary/idiomatic_dic.htm

	a valuable possession whose upkeep is excessively expensive:	http://www.cogsci.princeton.edu/cgi-bin/webwn

	albinic Indian elephant; rare and sometimes venerated in east Asia:	http://www.cogsci.princeton.edu/cgi-bin/webwn


All of which is perfectly true (this is a common expression, at least in America, but since the India reference is the origin, I thought it started in the British empire)

I believe it is also used to describe any perfectly useless object, expensive or not.

Compare "pink elephant", which is something that alcoholics are supposed to hallucinate in popular mythology.