I want to build a submarine?

Other answer:

Ok, so why do you want to build a su8bmarine and what type of submarine do you want to build ?

Su7bmarines can vary from the passenger subs used for tourist trips in the Barbados to full nuclear boats in current use. So what do you want

most home built subs do NOT go down to 100' but cruise around a 10 -20 feet down. Problems with pressure at 100' are considerable & mean a sealed vessel must be constructed unless you want to follow decompression tables every time you dive. Most easily (relatively) built subs are in the form, of a self propelled diving bell.
Better & cheaper & probably safer to learn to scuba dive competently
A strange title yes but a serious title. i have heard of people building submarines in their garage and have been seriously thinking about doing it myself but i cant seem to find any online guides/references. i was thinking of using a propane tank as the body and keeping it strictly electrically powered, also only need to go about 100ft deep (i live in Hawaii all the good stuff is within 100ft) has anyone got any links to actual instructions, guides, info etc… not looking for videos unless they actually explain things. Thanks!
Who am I?:
1. buy a leak-proof boat
2. bring it to a lake/reservoir/sea
3. turn the boat upside down.
4. hold the boat over your head – place your head into the footwell
5. walk into the lake/reservoir/sea
6. congratulations, you've built a sub.
Congratulations. Have fun. Try not die in the process.
P.S. Make sure it's water proof
Building a sub is complex and expensive but enjoy yourself dude.
Just buy one, it will be safer. Nuytco were showing some at my local boat show for about $1.5M