I have a late 70's Javelin under repair. The plywood under the foredeck is completely rotted away. I am unable to determine how the mast step was or should be configured. Does it sit on top of the plywood or does it extend through the plywood to the centerboard trunk below? I have what appears to be the cast aluminum step and this has two holes in the center that I assume would be used to mount the step to a surface. What type and size of fastener is used here? Are there any measurements available for accurate placement? Greatly appreciated… JBB