Zathabar's advice to have a stamina pot in your hotbar whenever you're at sea is spot on. Always having a stam pot handy when doing anything that includes large bodies of water is a lifesaver for sure. The odd Leviathan have very slippery backs, and trying to stay in one spot while swinging a pickaxe quickly drains one's stamina. I have had quite a few close calls while harvesting chitin through neglecting to manage my stamina wisely. Logging off quickly when stamina is gone while asea, is a cheezy way to get back a full stamina bar. Everyone loves a little cheeze now and then.