More then any other service a Navy REALLY has to stress teamwork and looking out for each other. Ships are very dangerous places by virtue of the machinery and many tasks necessary to keep them operational. Many of the rules exist for the sake of safety. Also, most Naval Services are very big on tradition, much of which dates back to the age of sail. While extremely outdated they do create a feeling of comradery with between sailors, you share a unique "culture" with them and are part of a select and highly skilled group. A good many naval traditions are internationally recognized and create a kinship with other sailors from anywhere in the world. Even in wartime most sailors look out for each other because the sea has no mercy.
So yeah, a good many of the rules, as ridiculous as some may seem, do have a purpose. Talk to any old Chief Petty Officer (or the equivalent in your Navy) sometime, and while he may chuckle a bit I assure you he'll remember that at one time it all seemed just as stupid to him and he'll explain "why" things are done the way they are.
And believe me if you think the petty rules are bad aboard a surface vessel talk to a submarine sailor sometime.
And if you think the normal traditions are ridiculous just hope you never cross the International Date Line or Equator. While I can't be 100% certain I'd bet your navy has a "ceremony" you'll remember for the rest of your life!
As to the cell phones and computers I can think of two very good reasons for restricting their use aboard ship.
1) Security - While no doubt 99.99% of your shipmates are loyal it only takes one to pass along info about munitions aboard, sailing schedules, or missions.
2) More importantly, electronic interference. Modern ships have more sophisticated and extensive electronics than anything else, except aircraft, in a confined space. The last thing anyone aboard needs is a random electronic signal from a cell phone or computer throwing off the navigational guidance equipment and causing the ship to run aground because the equipment said you were one place and you were really in another.
