Need help on translation

It's a tricky one. I'm guessing this is a nod to the idiom 'Sink or swim'? The problem is, you can't really translate an idiom well for one language to another.. especially in Japanese. So you have two options,
- find the direct equivalent saying in Japanese - like a good "yon moji jukugo" (4 character idiom).. which for eg could be something like "Ichi ka bachi ka" (meaning all or nothing)... but you can see that's not a direct translation.
- or translate the phrase directly.. which you could say in a fair few different ways.. there probably isn't one 'correct' one. This is because you are going to lose the connotations of the idiom no matter what and be left with context free sentence in Japanese.

So to have a shot at answering your question.. you could possibly say:
- 沈まない - Shizumanai - Will not sink/I will not sink/I won't sink/I refuse to sink
- 沈下禁止- Chinka kinshi - Sinking not permitted - Sounds awful to be honest..
- 沈むのを拒否する - Shizumu no wo kyohi suru - I refuse to sink - Doesn't sound great either, but a very direct translation.