September 30th 2003 - I chose channel over square tubing for several reasons. There is no place for moisture/water to settle and with tubing there is no way to seal the inside. Might be one of the reasons that almost all boat trailers are made from channel. In any event it's just a matter of preference and channel will be very strong in this application. Here the two inch channel is cut to length and is being clamped and squared up prior to welding. I clamped quarter inch steel plates at joints to line up rails prior to welding.