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Over the years I have replaced one traditional hatch , a traditional sliding companion way hatch and a butterfly hatch on my Fraser 36 . They were all well made , mainly wood and were works of art when freshly varnished . I truly admired the craftspeople that made them . They also all leaked , let in little , or no light in the case of the companion way hatch and were a maintenance nightmare . I replace them one by one over the years with 1/2″ acrylic sheet . I copyed the thickness of similar sized offshore commercial hatches to come up with the acrylic thickness . Hope I got it right . These hatches have changed what was a adequately bright boat below decks to a wonderfully lit boat below decks . Even on our overcast northern Pacific days . And they require little maintenance and they do not leak . Another big plus up here in Vancouver.
Your article on replacing windows has me puzzled though . I contacted the local Sika dealer rep when I started these projects . He pointed me to numerous Sika bulletins on glasing . Sika is big into this . Plus information from the acrylic manufacturers. What they said comes down to something like this .
– Do your proper surface prep .
– You need a 1/2″ deep bead of the proper Sika product of around 1″ width , for a 2′ to 3′ span of acrylic to allow for sufficient movement of the acrylic to avoid overstressing anything and or breaking the seal .
– You need a strip of uv blocking paint , I think mine was two inches, to prevent uv induced failure of the seal .
– I added a series of screws or bolts , with oversized holes through the acrylicfor expansion, to prevent an unexpected catastrophic failure of the hatches in case I got something wrong .
What you did not do was to rigidly bond the acrylic in place .
Maybe I misunderstood, but is what your adhesive tape does?
So far so good in the northwest.

1 COMMENT

Joe Easton October 27, 2023 At 3:19 am

Over the years I have replaced one traditional hatch , a traditional sliding companion way hatch and a butterfly hatch on my Fraser 36 . They were all well made , mainly wood and were works of art when freshly varnished . I truly admired the craftspeople that made them . They also all leaked , let in little , or no light in the case of the companion way hatch and were a maintenance nightmare . I replace them one by one over the years with 1/2″ acrylic sheet . I copyed the thickness of similar sized offshore commercial hatches to come up with the acrylic thickness . Hope I got it right . These hatches have changed what was a adequately bright boat below decks to a wonderfully lit boat below decks . Even on our overcast northern Pacific days . And they require little maintenance and they do not leak . Another big plus up here in Vancouver.
Your article on replacing windows has me puzzled though . I contacted the local Sika dealer rep when I started these projects . He pointed me to numerous Sika bulletins on glasing . Sika is big into this . Plus information from the acrylic manufacturers. What they said comes down to something like this .
– Do your proper surface prep .
– You need a 1/2″ deep bead of the proper Sika product of around 1″ width , for a 2′ to 3′ span of acrylic to allow for sufficient movement of the acrylic to avoid overstressing anything and or breaking the seal .
– You need a strip of uv blocking paint , I think mine was two inches, to prevent uv induced failure of the seal .
– I added a series of screws or bolts , with oversized holes through the acrylicfor expansion, to prevent an unexpected catastrophic failure of the hatches in case I got something wrong .
What you did not do was to rigidly bond the acrylic in place .
Maybe I misunderstood, but is what your adhesive tape does?
So far so good in the northwest.

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