Gene,

Your smily face there is confusing me, but your comment without it:

"Did you know most of the offshore CA gambling ships did not float?
They were on huge concret blocks layed and chained to the ocean floor.
In effect that had concrete hulls."

Is incorrect, to my knowledge. To my awareness, ships with concrete hulls (that float) are very common, then and now. (It seems that the huge pier that just washed ashore in Washington State (from the Tsunami in Japan) is a floating concrete form that doesn't need a cover to float.

Perhaps you meant that most of the offshore CA gambling ships did not have operating engines and needed to be towed from location to location, which was the case.

Jim