The eighth paragraph of the linked document, titled
The Liberty Ship: Unique Cargo Ship of World War II,
contains statements that are at least misleading and
possibly erroneous, in the opinion of the Webmaster.
This paragraph contains information found in personal notes
provided by an individual whose knowledge or expertise with
respect to Liberty ship construction or operation is not
specified. These notes state that their slow speed made
Liberty ships "... sitting ducks for submarines. So all ships
were reinforced by concrete from [the] bottom up to three feet
above water line..." However, at least the S.S. JOHN W. BROWN
does not have such concrete reinforcement in its hull.
Additionally the Webmaster has found no evidence elsewhere in
other information sources of such reinforcement being standard
in Liberty ships. In any case it is questionable whether
concrete reinforcement of this nature would provide any
significant additional protection from submarine attack as is
implied in the linked document.
The same paragraph notes that Liberty ships were "fitted with
a degouzing (sic) cable around the inside of [the] ship. An
anti-magnetic field created by a generator current sent
through this cable caused the ship to repel magnetic mines
and torpedoes."
The correct spelling of the term in question is 'degaussing'
cable. Degaussing is the process of reducing
or eliminating an unwanted magnetic field. To oversimplify, the
effect of the current sent through a ship's degaussing cable is
to offset the change in the local magnetic field caused by the
passage of a steel ship over or near a magnetic mine. The result
is not to set up an 'anti-magnetic field' or to 'repel' a magnetic
mine but rather to render the ship undetectable by a magnetic mine
in the area. Degaussing offered little or no protection from
torpedoes, most of which during World War II relied on
contact detonators rather than on magnetic
detonators.