Do I need breathing aparatus for the Collasium?.
If so where do all the crabs hang out?.
Just completed Anephas Shrine and only have one character with full breathing kit.

its been a while since i've played but i do believe you need the underwater breathers in the Collesium (unless you have the Breath of Air spell and a few good healing spells) and in order to find crabs, just but your monster spawn to often and "steal" the shells from the crabs...

It is possible to do the Cooooollasium with out breathers...but it's rather difficult. You have to find all the little air pockets...and Save alot. The rotating room...can be especially tricky.

Tis is one of the times when the scout skill comes in handy. Nothing like cruising around the lost sea, surfing the waves, when suddenly, someone says, "Hey! I think I smell some crab!"

That's all it takes for everyone to jump overboard and head for a crab cookout.

And stealing is a much better way of getting the shells, too. Every time you steal, you have a chance to get a shell. If you kill a crab, you get one chance for a shell. So keep stealing until you get one, and then kill it.

Seems to me the boatmaster can make a breather and helmet from a single shell, so you'll probably need to do the shell thing twice.

Damn I never collected those crap shells! Thay jsut too so much 'room' from my back...
How to make those breathing aparatus?

You do not need the undewater breathers - if you have Athletics high (preferably 12), the Breath of Air spell and the Restore Health spell. Also, the Irong Lung trait is extra helpful in Collasium (Thief guild level 5 trait but only for some thief classes. Barbarians can buy the trait. Perhaps, bards can buy it, too. Assassins cannot buy the trait. Another source of the trait is the Ring of Neptune, which you find in Collasium.) I am always doing Collasium without the breather.
If you want the breathers then you need 3 shells for each breather. Take the "quest" in the Docks of Brimloch Roon and sell the shells there. Every time you bring 3 shells you get (can buy? I am not sure now.) one underwater set, i.e., a helm and the breather itself. The breather looks like the shell.
If you plan to go though Collasium without the breathers then test the idea first: swim underwater around in the sea and see whether you are able to restore your air supply efficiently. This might be a problem for big parties. I am always going solo so that I have to heal only one character. Therefore, I am always enough efficient even without the Iron Lung trait.

Personally, I prefer using the breathers than trying to do Collasium without them. Far less concern about your characters drowning.

The scout skill is, as mentioned, very useful to locate crabs. I just sailed around in my ship until my scout said there were crabs nearby. Then I would jump overboard and find them. You can pickpocket shells from crabs sometimes so that's worth a try.

You don't have to take your whole party with you to Collasium. Many players have gone with only 3 members of their party to avoid having to collect shells for all. I like taking everyone! ;)

Wyv

To convert the shells to breathers and helms, take them back to the shipyard and sell them to the shipmaster. You can then buy back breathers and helms.

You have to sell them in threes, so be sure to collect three shells before heading back.

Thanks guys, none of my team can get Iron lung sadly so it was the Crab Cookout option I used.
My 1st guy has Scout at 9 so he was able to pick up when there were crabs about, the pickpocket option on the crabs worked really well, I now have full kit for all.
I guess I've nearly finished this game now?.

Yep. You're getting really close... the pyramid is the last dungeon you will do to complete the game.

And congrats on getting all the breather equipment. Makes life easier, doesn't it?