A dock and dock kit suitable for shipping from a manufacturing site to an erection site where a dock can be erected having elongated dock beams with a length that is greater than the length of any of the beams in the dock kit and the mateable beams have surfaces that are mateable and securable to each other through fasteners to form elongated dock beams with each of the mateable beams having supports thereon for receiving and holding a plurality of dock planks thereon.