Gday Marmca, I have gone through the process on our old Lagoon
410. Some of the work
we did ourselves and the other we had done by Shipwrights. Our front window were starting to come away from the sealant
. The shipwrights slowing and carefully used a thin wedge slowing cutting through the sealant
. When they had a enough room the placed a thick fishing
line through the sealing and then wrapped each end on a round dowel. With a person on the inside and one of the outside they started to pull on the seal with the fishing
line and gradually pulled though the sealant and moved the wedge as they went. When the windows were removed we then removed all the sealant still around the window frames.
We chose to go with standard poly carbonate as it does not scratch or mark as Lexican does. We just took it to a Plastic cutter
and he was able to bend and cut it to shape then drill out the required holes.
The shipwrights fitted the new plexiglass and I refitted the hatches. To hold the plexiglass in place the shipwright cut several elongated pieces of timber approixmate 150mm long and 25mm about 12mm thick. A small hole that fitted a large screw was drill in the centre of the timber. Its then a case of once fitted on the sealant place the timber equally on either edge of the frame and plexiglass and screw into the space between the frame and the plexiglass. Do this for the 8 or so timber supports around each window. Leave for a couple of days then remove the screw and timber. The adhesive
should then be cured at this stage and hold everything in place.
Make sure you tape around the frame and the plexiglass to stop sealant spreading on the new window and frames fo the boat