In the days before fiberglass most, but not all boats had a long keel with attached rudder. This was to a great extent due to the limits of plank on frame wood construction. A more efficient fin keel wasn't a good match for the construction method. The full keel was shortened over the years to reduce wetted surface, improving light air performance. In the process the rudder was moved farther forward, reducing its effect. The earlier fiberglass boats were for the most part a copy of this design type with a different material.
As designers and builders became more experienced with the material design improved, leading to easier to handle more nimble boats with rudders aft, making the boats easier to handle.
I am not suggesting that any fin keel spade rudder boat is the best choice for offshore use, but modern designs can sail well in both light and heavy conditions and can be very suitable for ocean crossing.
Here's an old but fairly successful fiberglass design.