Repairing gouge in rubbing strake

[mriley]

I have an unsightly gouge in my white, hard 'rubber'(not sure of actual composition but it is a pretty common item) D-profile rubbing strake, about 5mm deep, 5mm wide, by 30mm long. Any ideas how to fill/repair it. I have tried marine sealant, but that just peeled off after a few weeks. Any repair would ideally be self coloured (so as not to have to paint it). Thanks in advance.

 

[matthewriches]

What boat?

 

[Concerto]

It probably came from Wilks if the boat was British made. Use this link and check, then buy a new insert.
https://www.wilks.co.uk/marine/boat-fendering.html