I think it does provide some bracing for the hull, but it also supports the maststep and centerboard rigging. I cut a couple of access openings in the cuddy floor of my DS II to rebuild the maststep area and then made the openings into covered access/stowage hatches (I have one just ahead of the mast that includes a shelf resting on a box beam that runs from the forward bulkhead to the mast, that keeps the baskets of iteams stowed there up out of hte bilge. Under hte cuddy floor there is a plastic pipe that is supposed to be directly under hte maststep..... mine was just forward of the step and so the cuddy floor broke allowing hte mast step to drop a few inches. I originally installed a 1/4" aluminum plate under the step (about 9" x 12") and also replaced the rotten 3/4" plywood under the floor (about 8" square) that originally backed up hte maststep under the floor, step and CB blocks were screwed into that and after 17 years had rotted out. The last time I rebuilt the mast step (2006?) I moved the pipe to line up with the maststep, and again replaced the plywood (I had not sealed it properly the first time). Boat is rock-solid now! I can tel lyou more or take more pictures if it will help!