Many thanks Fredo, very useful. By Carloway do you mean the bit in the inner loch where the boats are moored, I wasn't sure if there's also one at the pier or not?Carloway slip is safe to use at all stages of the tide and is in a very sheltered location.
Portnaguran can, I think, be used at all stages of the tide although it is exposed to west winds......use Brevig in a westerly!
Port of Ness can be used at all times aside from low water, but it is very exposed to south or east winds and it is unusable in any swell (which may be coming round the island from the west)
No idea about Skigersta.
That Bragar slip looks excellent, though a bit of a steam to the Carloway fishings. Are there any decent marks nearer Bragar? - not looking for any state secrets on the forum, just pointers in the right direction.I think Brevig is useable at all stages of the tide, and getting in and out of the harbour is ok except in a strong SE wind.