There is no reason to steam any part of a cold molded boat. If the piece wont go it means that it is too thick. Cut it thinner and do a lamination of two thinner pieces. The amount of work it takes to build a steam box etc you can laminate all of the ribbands on the boat. I am not a fan of taking perfectly good and dry wood, that we pay extra for to be that way, and add water to it. A little finesse goes a long way in fitting ribbands.