What makes the hatch acrylic go crazed?

[tudorsailor]

I am thinking of getting new hatches (long story). Mine are from 2001 and severely crazed. Here in the Med I see lots of lots of yachts with fabric covers over their hatches. Do fabric covers really works in preventing the acrylic going crazy? Is it the UV that does the damage or the heat or a combination of the two? Is fabric sufficient? I also wonder about more modern boats with flush hatches how they would keep protection in place

TS

 

[Sianna]

UV causes the problem, you can replace just the acrylic, my brother replaced 5 of his using Eagle Boat Windows:

Boat window & hatch refurbishment | Eagle Boat Windows | England

Apparently they were very easy to replace, on the acrylic, usually under the rubber gasket there is a serial number which Eagle can match to pre drill hinge holes / handle holes etc. The hardest job was cleaning the frame once the acrylic came out, but all materials needed, acrylic, adhesive etc were supplied for around £100 per hatch

I'm just about to replace my acrylic on my lewmar 44 as mine is a 2003 boat that only been in the UK and is still very crazed.

 

[HughClayton]

Acetone will also craze polycarbonate.

 

[Sandy]

I use fabric covers on my hatches in order to sleep during daylight hours. On the odd day when we have some sunshine they keep the cabins cool.

 

[tudorsailor]

UV causes the problem, you can replace just the acrylic, my brother replaced 5 of his using Eagle Boat Windows:

Boat window & hatch refurbishment | Eagle Boat Windows | England

Apparently they were very easy to replace, on the acrylic, usually under the rubber gasket there is a serial number which Eagle can match to pre drill hinge holes / handle holes etc. The hardest job was cleaning the frame once the acrylic came out, but all materials needed, acrylic, adhesive etc were supplied for around £100 per hatch

I'm just about to replace my acrylic on my lewmar 44 as mine is a 2003 boat that only been in the UK and is still very crazed.

I had a seal on one hatch replaced last summer. Nightmare getting the frame off the seal. The screws that hold the frame connected had corroded into the frame and had to be drilled out. Then a new plate fashioned to take new screws.
As with all things on an older boat, not as straight forwards as I initially thought. Oh and it still leaked in the next rain storm.
TS

 

[europe172]

I am thinking of getting new hatches (long story). Mine are from 2001 and severely crazed. Here in the Med I see lots of lots of yachts with fabric covers over their hatches. Do fabric covers really works in preventing the acrylic going crazy? Is it the UV that does the damage or the heat or a combination of the two? Is fabric sufficient? I also wonder about more modern boats with flush hatches how they would keep protection in place

TS

I believe cast acrylic is less sensitive to uv than rolled acrylic, if specifying new hatches go for cast

 

[Iliade]

...And don't leave the protective film on in the hope that it will help.

You can guess how I know and if anyone has any better ideas than just letting it degrade to the point at which it all falls off, do let me know.

 

[thinwater]

You can secure fabric covers using SNADs without drilling. They are surprisingly good, for something light duty like covers. I keep my windows covered. When I sold my boat (20 years) I had vinyl windows that had always been covered (sunroof) and they were still soft and like new.

https://www.ykkfastening.com/products/search/detail.html?pdid1=SNAD(R)

 

[Neeves]

We made covers for all the windows on Josepheline. Not to reduce UV damage but simply to reduce the impact of sunlight, reduce the brightness and heat.

We did not have crazing but windows cracked (after 25 years)

We know of one catamaran, again in Australia, owner built that had no saloon windows (for the same reason) reduce brightness and heat.

I don't know what SNADS are - press studs or sail track (plastic) works very well.

Jonathan

 

[trbt]

Often the crazing is caused by using alcohol-based cleaning products.
Here's and answer that explains it: Why does alcohol crack acrylic (plexiglass)?
And some more links to see the effects:
Do not clean Plexi glass or Acrylic with alcohol
How to NOT destroy your acrylic!
DON'T Clean Acrylic With Alcohol!! (Methyl, Ethyl, Isopropyl, or Acetone.) This includes VR Lenses!!