Hatch acrylic thickness

[Tim O]

I've just taken the old cracked acrylic out of my Gebo hatch to find it is 8mm thick.

Is there any reason not to replace it with 10mm acrylic which I presume is stronger.

There seems to be sufficient adjustment room in the inner and outer part of the handles to cope with this.

The surface will be slightly proud of the aluminium frame but is this a problem?

 

[bluerm166]

It will make it harder to tool off the sealant which is easy to knife off flush when it has gone off.
But I have decided that deflection in the acrylic of typical 8mm thickness when people stand or sit on it makes it prone to leakage of the perimeter seal.

 

[Plum]

I've just taken the old cracked acrylic out of my Gebo hatch to find it is 8mm thick.

Is there any reason not to replace it with 10mm acrylic which I presume is stronger.

There seems to be sufficient adjustment room in the inner and outer part of the handles to cope with this.

The surface will be slightly proud of the aluminium frame but is this a problem?

I recently replaced the acrylic in two Lewmar hatches. The larger one was 10mm and the smaller 8mm but i replaced both with 10mm without a problem.

Www.solocoastalsailing.co.uk

 

[Tranona]

8mm is more than strong enough, which is why it is fitted originally. Polycarbonate is stronger for a given thickness if you are really worried!

 

[Aja]

8mm is more than strong enough, which is why it is fitted originally. Polycarbonate is stronger for a given thickness if you are really worried!

But polycarbonate doesn't have the same UV protection as acrylic and will go opaque quickly. That's why Lewmar et al use acrylic.

Donald

 

[Tranona]

But polycarbonate doesn't have the same UV protection as acrylic and will go opaque quickly. That's why Lewmar et al use acrylic.

Donald

It is still stronger which is what the OP is concerned about. UV damage can be significantly reduced for both acrylic and polycarbonate by having canvas covers over hatches. Useful if sailing the tropics or Med.

 

[Tim O]

How quickly does polycarbonate go opaque? Are we talking years? It will be in the UK, and I plan to get a cover for it

The plastic suppliers I took the old acrylic in said they might have an offcut of 8mm tinted polycarbonate big enough to do the job, and cheap cause it's an offcut...... or they have 8mm or 10mm acrylic.

If 8mm acrylic is strong enough maybe I'll stick with that....

 

[Tranona]

If you have a cover it will probably outlast your ownership. I have found acrylic crazes and goes dull as quickly as polycarbonate and only use the latter now. So my advice is go for poly.

 

[alahol2]

If you are at all worried about the strength of 8mm try and smash what you've taken out. I suspect you will need a sledge hammer to do it.

 

[Tim O]

I've heard its incredbly tough.....But not tough enough to withstand My Hermes couriers who cracked it in the post, hence the reason I'm having to replace it! (It was a second hand hatch... Definitely no cracks before it went in post!)

 

[alahol2]

I suspect they carry sledge hammers for just this sort of problem package.

 

[Aja]

It is still stronger which is what the OP is concerned about. UV damage can be significantly reduced for both acrylic and polycarbonate by having canvas covers over hatches. Useful if sailing the tropics or Med.

Would you like to suggest one manufacturer or supplier of yacht hatches that have polycarbonate glazing? I'm not talking about the replacement market as that is very different.

Regards
Donald

 

[Tranona]

Would you like to suggest one manufacturer or supplier of yacht hatches that have polycarbonate glazing? I'm not talking about the replacement market as that is very different.

Regards
Donald

No, but that does not mean it is not suitable. I have a companionway hatch in polycarbonate (which I made myself) that has been on the boat since 1992 and is still fine.

 

[Aja]

I agree that polycarbonate (specifically Makrolon which is polycarbonate with a special UV coating and is eye watering lay expensive at the cut sizes needed) is suitable - say if you were crossing oceans it would be my material of choice. But for coastal cruising it is overkill. Perspex (trade name for acrylic) is guaranteed UV stable for >10 years. Untreated polycarbonate would be stable for about 5 years.
I also have washboards that I fit for the winter which are plain polycarbonate, purely because it, like bus shelters and trolley bay sheds at supermarkets is almost impossible to set fire to or to smash. They do scratch very easily but I'm not too bothered about their cosmetic look.

Regards
Donald