I don't have dimensions for you, but I will suggest you stay clear of the round boom on the N20's. The only N20's that were equiped from the factory with round booms were the Alter cup boats last year, and that (per my understanding) was due to a shortage on the ususal rectangular booms. The round booms on the 20 were too flexible and caused problems with sail shape under hard sheeting loads. Most of us have already swapped out the round booms for the rectangular. (including me)