Yes, that’s the thing, it takes a bit of courage to start taking them apart knowing that if you make a mistake, that it will cost you quite a lot of money.
I was fortunate in a way because someone, who had their boat ashore over winter in the boatyard where mine also spends the winter months, had replaced a whole deck hatch with a new one and had discarded the original complete with its entire aluminium frame. The normally transparent acrylic within the opening frame was badly crazed, but I saw this as something that I could use to practice dismantling before having a go at the hatches on my own boat. Taking the old discarded hatch apart proved reasonably easy, and that gave me the confidence to look at changing my own deck hatches.
In regard to the portlights, I purchased two new sets of brand new Lewmar portlight lenses, only to discover they would not fit my existing portlight frames because of the changes Lewmar had made to the hinge arrangements. I had to go back to the supplier and buy a set of brackets and hinge bolts etc., in order to fit the new lenses. Removing the original brackets was difficult, but I was lucky, and despite the difficulties I was able to remove each of the securing screws for the brackets on the two forward portlights within the main cabin. But I was deeply disappointed when trying to tackle the remaining four large portlights on my boat, because the securing screws, like the one marked with an arrow in an earlier reply to you, were not going to come out easily.
Being able to replace the two forward portlights in the main cabin left me with two old but intact and thoroughly crazed portlight lenses that I could have a go at trying to dismantle and remove the plastic hinges and catches. After a couple of mistakes I found that I could remove those plastic parts and then began looking at how to stick them back on and also where to get the acrylic lenses made up locally. I was lucky on both counts in that I found a compatible and superbly strong adhesive, and a plastics manufacturer with the right kind of machinery to be able to accurately cut out new lenses Including machining out those recessed areas. The rest, as they say, is now history !!
Also, although I now have two slightly tinted original Lewmar replacement portlights and two non tinted locally made portlights within the main cabin on my boat, up to now no one visiting my boat has spotted the difference. Indeed, in all honesty and despite that I know there is a difference, I’m hard pushed to notice it myself.
