Finally got the rubbing strip back on. All the existing screw holes were ok but I did buy new screws as the old ones were mashed up from rubbing on the ground.
I used butyl tape to seal the holes – a strip under the head to help avoid electrolytic corrosion and another strip wrapped around the screw to seal the hole in the boat. This meant that I had to put all the screws into the strip before fixing to the boat but that worked out ok.
Hopefully this will keep the water out – we’ll see…
I also started playing with ballast. I’ve been saving milk cartons and I can get 6 or 7 in the right location under the floorboards. I think I can get them watertight with the aid of PTFE plumbing tape under the cap.
I’d really like around 40kg in total but these cartons only hold 14l each side or around 28kg total when filled with water. Can have a play and see if it makes a noticable difference.