G'day, how much chain were you considering?
I'd think 30m of 6mm certified/rated gal chain with 50m of 12mm nylon would be great if your trying to keep weight down, I haven't looked into it, that's just off the top of my head. Look into the SWL of the certified 6mm chain.
cheers

It is not just the strength but the weight of the catenary that is important. If you are going to spend some time in chop then I would veer towards the heavier chain. Pulling chain tight is never fun and should be avoided - the 6mm has much more chance of straightening in a nasty blow, which would not be good.

If you are going to the coral you will need 30 metres of chain which weighs about 50kg (8mm). I would recommend an anchor winch and look at a way of getting the chain weight back in the boat as far as the mast bulkhead. Then you can have heavy chain and a nice sailing motion too.

On my 32 footer when heading north I have 100metres of 8mm chain. Glad I had it when caught in one of those storms two years ago . In my opinion there is no better peace of mind than to have more than enough chain on board. It may not do anything but it makes you feel better when that wind blows.

Thanks everyone, I normally have 30mtr of 8mm chain plus around 40mtr of nylon. However as my back is not what it was I was thinking of running 6mm all chain to avoid chafing . I would never tie off hard on chain(great way to damage things) and always use a nylon snubber. I could run an anchor weight down the cable to help with the lay of the chain. Its just that an all 6mm chain is lighter than an all 8mm chain on a small boat.
Thanks
Winkali