Hello kersau,
that indeed sounds very similar to what is going on with the boat I’ve been looking at. Although there is not quite as much water entering with this one.
I am sorry, the ‘salmon’, is that the keel element? Because I only know the fish salmon, but the word also came up when translating your and others’ posts with Google Translate.
[…] reopen the joint on each side at the top of the salmon and fill it well with sikaflex then sealants?
This is what the guys wanted to do here: Sand away material so there is a good gap there and then fill that up with Sikaflex. And that’s also what the current owner of the boat ordered to be done now, as the price for that was very reasonable (150 EUR). He then wants to put it back in the water and see if that fixed the problem already. Although of course while it may slow down or stop the issue of water entering, the (substantial) structural damage done by the delamination that has already happened is not going to be addressed by that.
But I will let the guy know, that he should really do a good session, to know if this helped or not. And I can also let you know what comes of this of course!