Window Replacement
My Cat 25 has screws in the acrylic. Sealant was then used to seal the window. Later Cat 25s did away with the screws because the sealant had such a tight bond the screws were not needed.  The screws could also be a source of stress fractures and so eliminating the screws during replacement of the window not only cuts down the installation burden but may reduce any possible need for rework.  (Catalina Yacht's Parts Department can provide the acrylic window replacment but not for Catalina 25s that also have the aluminum frame.  An exact pattern must be taken of the window to be replaced and mailed to their Parts Dept.  I taped 8 1/2 X 11 sheets together and then taped it over the old window that had a crack in it - traced the pattern and mailed that to them.  The Parts Dept will then call you to finalize/process the order.)

Catalina Yachts indicated that the sealant used for the windows is:
Dow #795, Catalina Part #24605 and the cost on 3/19/08 was  $10.10 per tube - 1 tube per window which can be ordered from their Parts Department.

In regards to the second drawing below, Catalina Yacht's Technical Deptment offered the following information:
"When they have done it here I have not seen them need the weight fixture, so that might just be for smaller boats with more curve in the deck. "
My own spin on this is to consider something to put pressure on the window until the sealant cures.  Perhaps the use of a pad resting along the full length and width of the window and held in place by wood slats wedged between the fiberglass deck lip and the pad . Mid-way up the wood slats, some weights could be tied to apply some force to the window and aid in attaining a good seal/bond.