Green’s Dictionary of Slang

steamboat v.

1. (US) to cheat, to defraud.

Reno Gaz.-Jrnl (NV) 13 Mar. 1/5: [headline] An Intelligent Man ‘Steamboated’ by a Soldier boy who Gave him a Great ‘Fill up’.
News-Review (Roseburg, OR) 1 Aug. 4/7: As they left they complained of being ‘steam-boated’ out.

2. (drugs) see cit. 1969.

[US]R.R. Lingeman Drugs from A to Z (1970) 233: steamboat [from the resemblance to a steamboat smokestack] To inhale the butt of a marijuana cigarette stuck in a hole in a toilet roll, the hand enclosing one end, the mouth on the other end. Since the butt is too short and hot to hold in the fingers, it is inserted in the roll, which traps the smoke to be inhaled. Thus none of the smoke escapes, and it is cooled. Marijuana users believe that the concentration inhaled mixed with air, or ‘hyperventilated,’ is greater in potency.