i was working in the vast seas of shadecrest and i encountered a problem, I could place blocks in me, and soon enough i was suffocating in blocks. For instance i was placing blocks in front of me moving back fast to keep up the pace, suddenly the blocks caught up and were bashing my head in like i was defecating on their floor or something. Also, before that i was placing blocks on the floor and whenever i did that they would move me and push me all over the place. aka blocks can man handle you in the ocean, even if you are a sharq i don't know if it is a server bug or a minecraft bug. http://www.minecraftforum.net/topic/781098-minecraft-bug/ ^ i posted it on the official Minecraft forum to see if Mojang can help
I had the same thing happen to me last night. I was in a tunnel that had water in it. There was enough room for me to place one block before I would be in the way, but it allowed me to place two blocks. The second block was placed where my head was and I had to log out to keep from suffocating. I thought it was odd but did not give it a second chance to suffocate me