Hi all .
Yes I have smoked #Fish in a large Boiler I just put a riser Cross of 2" or 25 mm then I fitted a baking rack on top of that to hold the fish or what ever you wish to smoke.
Then you put the wood shavings on the bottom of the Boiler ,
place the fish on the rack .Then I just put the boiler with the lid on ,On to gas stove .Outside and in about 15 -20 min.
Wollar smoked cooked fish fillits.
It worked fine for me
Cheers Hasa