Hi! This has a lot of symbolism that I'm not sure I can uncover but I'll try my best. You said you had to pass through seaweed but you hate seaweed. Maybe the seaweed represents an obstacle you have to/are going through in your waking life . Any "seaweed" in your life that you have to get through currently? I see submarines as going into the unknown, going into your subconscious. Water usually represents emotions. Also, are you having any questions about death, by any chance? Do you find yourself thinking about it? Just curious because of the dog tag part in your dream. Dog tags are used to identify others. Do you feel like you've lost a part of your identity and you're trying to find it?