We have used the Sikaflex, and it seems it works well! So thanks for the advice.

We have now however arrived at another challenging step. The boat is 20 years old, and the result of that is that the parts which were once a rough surface, bacame slippery. (like e.g. the hull covers) In rough weather conditions, this sometimes causes interestiung situations!

I remember reading something about mixturing sand / silica with gelcoat to overcome this problem. I cannot find this however here on the forum anymore.

1) Is there anybody who has done this before?
2) What "sand" did you use?
3) Can you describe how you did it?

Or is there another manner of dealing with this challeng?