Grimrock

Hi i have two things to solve. 1) In keelbreach bog there is closed gate underwater heading to south how can i open it, is there another location to visit this way?
2) In keelbreach bog there is a rock witk "underneath" sign on it. I saw somewhere that there should be chest do you know how to get it?
3) How do i enter "SPOILER" in this forum?

Thanks

Hello

1: - no, thats the sea (apparently)
2: you should already have what you need, as its given to you pretty early on. 3: when posting theres a button that says spoiler....

Thanks for reply. I really dont know what to do in 2) How to get it.