Just to echo Mike’s comments about not walking on the hull and references to belly fluff….
Helene has 6 1/4″ boards which fit onto the stringed between ‘hog’ and bunk side, with battens to space between to space them out.
They can be seen in this photo of Helene when I bought her https://atalantaowners.org/a124-helene-broker-003/
Helene’s are actually a tight fit, particularly once they have been stood on. I like the arrangement because it maximises headroom. It would be simple to add wooden turnbuttoms to the bunk sides to keep the boards in place. They are held in place already by the ‘hog’ dues to the acute angle between hull and ‘hog’ vertical side.