Should the deck of my 17' American heave up and down like it's breathing when under sail? Recently purchased this boat and the rigging seems too soft. No back stay. Double side shrouds with spreaders. The front stay seems not too tight. But under the cabintop mast step, there is no support to the keel. Anyone know how, or if I need to strengthen this situation? I've tried to tighten the side shrouds, but the front stay still seems to have a lot of give. Thanks Jeff