Granted Patent
Utility
US 4,646,672 · App. 06/567,228
Semi-subersible vessel
Inventors:
William Duffy Bennett, Walter Michel
Patented Case
View Patent ↗
Granted: Mar 3, 1987
Filed: Dec 30, 1983
Inventors
William Duffy Bennett
Walter Michel
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.