Sub tid bits ...

[MarkShot]

I am reading two volumes on use sub design history. So, I am going to throw out a few interesting things here and there from time to time as I read. Here goes:

The very earliest designs called for depth control by use of a vertical screw. Problems with this approach included safety. (a good design should result in a sub rising to the surface if systems fail) It resulted in a fair amount of instability as diving was done with partially flooded main ballasts which led to lots of water sloshing around.

The above was ultimately abandoned in favor of fully flooded main ballast tanks and using trim tanks to maintain fine buoancy trim. Hydroplanes and forward motion was elected as the means to hold a sub down with slightly positive buoancy.

Early subs around 1900 sported some interesting features. Underwater bells for signaling. And designs by Lake which had retractable wheels for running on the bottom and a divers hatch (for work on underwater cables and mines). The early subs were initially intended for Harbor defense.

Early designs lacked periscopes and navigated by porposing (periodically breaching) to correct bearing. Early periscopes were fixed structures which did not even rotate.

Various hull configurations were tried, but ultimately ballast and fuel stores were moved outside the pressure hull.

Bulkheads were initially introduced partly to prevent flooding in case of collision, but more so as initial means to strengthen the pressure hull.

Around the 1900s, the USN began taking a greater role in developing RFPs and involvement as opposed to the earliest submarines were totally under the design control of the private builders. The two around this period were Lake and Electric Boat (Holland one of the founders left/driven out around the beginning of the decade).