capn billl,
Wow, I didn't know it was that bad with failing acrylic! I wonder if the cracking issue is the same for other brands of catamarans with large
saloon windows? This discussion might be worth taking to a broader forum to include all large catamarans with big windows.
The combination of the brittleness of acrylic, the very large thermal expansion rate of acrylic and the huge windows used in a Cat with the twisting action between the two hulls may all be combining to simply be an unresolvable issue. This is more reason to consider changing away from acrylic to glass or polycarbonate.
Polycarbonate is extremely strong, but also very vulnerable to both UV and scratching, so if anyone goes that direction, be certain the polycarbonate has both sides covered with a UV / scratch resistant film. The upside is that polycarbonate is so strong, it can be thinner.
Glass must be laminated and possibly tempered as well and fairly thick to have adequate strength, but still there is the potential risk for breakage. Laminated
safety glass is the way to go, because its much stronger than a monolithic panel and it will stay together when broken, but glass is heavy. Two 1/4" laminated
panels are slightly more than twice as heavy as 1/2" thick acrylic. Do not use the standard PVB interlayer for lamination, because it is vulnerable to
delamination in wet environments. Use EVA at a minimum, but by far the best is an SGP interlayer (ionoplast) to make SentryGlas.
All window choices have tradeoffs in cost / performance / weight / scratch & UV resistance. Choose wisely and also choose your sealants wisely.