I used Partite MA7300 which is a two part adhesive purchased through ebay or alternatively Plexus MA300 which is the same stuff. It comes in a plastic twin tube pack that needs either some careful manipulation to obtain a 50/50 mix, or the sellers may also be able to provide a dispenser gun shaped device which also comes with some mixing tubes. The dispenser costs about twice the price of the adhesive, but you can retain it for any future use. The mixing tubes have to be disposed of after use. The adhesive is very strong indeed and has a short period of working life of about 30 seconds in which you need to get the mixture in place and the catch firmly pressed onto the acrylic window. Don’t overdo the amount of adhesive you put onto the portlight catch, it only needs a thin smear, and do make sure both surfaces are clean and free from grease or water, and that the catch is put accurately into place. Then allow the adhesive plenty of time to cure before you put pressure on to it, 24 hours should do the trick. I used a small carpenters chisel to remove all traces of the original adhesive from both the hinges and catches and also from the acrylic lenses. I posted an article on this website about replacing the Lewmar crazed acrylic portlights and hatches. This was a couple of years ago and it had a heading of something like Crazed Hatches and Portlights if I remember correctly.
