Tips on how to make surface-mounted windows look good?

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WiginAesthetic

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Hello,

I have a cobra 850 and want to replace the windows as the existing acrylic has faded and yellowed. The windows currently are surface mounted, screwed straight onto the hull.

I have investigated having frames made for them, as I hate how they look. However, all practical considerations (ease of installation / maintenance, cost, not having to have frames made, etc.) point to just replacing like-for-like with a new piece of acrylic.

I don't want to make my life 10x harder than it needs to be for the sake of aesthetic so as a compromise, I thought I'd reach out to see if there are any tips on how to get the most out of surface-mounted windows?

Thank you,
Eddie

In case anyone wants to see what I'm working with:

IMG-20250422-185238 hosted at ImgBB
 
For a start I'd go for grey tinted windows, they cut down very little light from the inside, but hide the 'frame' from outside. I see it is also possible to get black stainless steel machine screws which should make it look sleeker.
 
I think they look ok.

Acrylic is cheap, especially if you cut it yourself.

I would simply replace them and do a tidy job.

Keep them washed and they should last. Polycarbonate is stronger but scratches more easily I think. Unless I have that in reverse.
 
On a previous boat, a Jeanneau Sun Odyssey 29.2, the borders/edges of the acrylic windows were painted silver.

This hid whatever sealant was there from sight, protected the sealant from sunlight/UV (which degrades certain sealants) and to be honest, made the windows look like they were framed..

The silver never seemed to wear off..

Photo example below from the internet..

Screenshot_20250518-221827_Samsung Internet.jpg
 
Last edited:
I've seen silver painting as well and as pointed out above is hardly distinguishable from aluminium frames, certainly not from a distance.
 
Martin_J said:
On a previous boat, a Jeanneau Sun Odyssey 29.2, the borders/edges of the acrylic windows were painted silver.

This hid whatever sealant was there from sight, protected the sealant from sunlight/UV (which degrades certain sealants) and to be honest, made the windows look like they were framed..

The silver never seemed to wear off..

Photo example below from the internet..

View attachment 193612
Click to expand...
Plus its rounded off, which IMO looks better than the sharp but slightly irregular corners on your original.
Though eye-of-the-beholder of course.
 
With modern sealants you don't need screws into the coach roof.

Many yachts, much bigger than yours, use 'glued in' windows.

Make paper patterns of the windows and take to an acrylic supplier. Have them cut and the edges rounded off and polished. Abrade the overlap of the acrylic where you will apply the adhesive/sealant. Mask the windows. Clean up the old covered surface.
Apply the sealant to the coach roof, plonk the new windows onto the sealant (this takes two people one inside and one out. Apply pressure to squeeze the sealant out - have weights handy to keep the windows in place and to follow any bend of the acrylic.

If this concept cuts the mustard I have pictures of when we did ours.

Jonathan
 
Mine are just darkened acrylic screwed and sealed to outside the cabin side. The edges are chamferred to ease the sharp edge. The sealant can be seen form outside but ok by me. Perhaps I am just not so fussy. I have replaced original windows then later one window and one now really needs replacing due to crazing. ol'will
 
Neeves said:
With modern sealants you don't need screws into the coach roof.

Many yachts, much bigger than yours, use 'glued in' windows.

Make paper patterns of the windows and take to an acrylic supplier. Have them cut and the edges rounded off and polished. Abrade the overlap of the acrylic where you will apply the adhesive/sealant. Mask the windows. Clean up the old covered surface.
Apply the sealant to the coach roof, plonk the new windows onto the sealant (this takes two people one inside and one out. Apply pressure to squeeze the sealant out - have weights handy to keep the windows in place and to follow any bend of the acrylic.

If this concept cuts the mustard I have pictures of when we did ours.

Jonathan
Click to expand...

An important detail. There are only a few sealants that can stay bonded when hit by UV from the bond side. Sika 295 with the correct opaque primer. Dow 795 (no primer) is probably more popular, certainly in the US. Most sealants, even UV resistant, will fail when the UV hits them right on the bond side. Make sure that your choice is rated for bonding glazing.

Most common sealants will be great for 5-10 years ... and then will start to fail. Sika 295 with primer and Dow 795 are good for the life of the window.
 
You're overthinking it because the current window itself looks manky and the sealant is a right mess.

Neatly cut light smoke acrylic, dark sealant not slapped all over the place and Bob's your mother's brother - they'll look neat as ninepence. Raised head slotted screws would also look a lot better than the current phillips - I'd use fewer than the current proliferation, and further from the edge of the fibreglass (if that doesn't affect the interior trim)
 
WiginAesthetic said:
Hello,

I have a cobra 850 and want to replace the windows as the existing acrylic has faded and yellowed. The windows currently are surface mounted, screwed straight onto the hull.

I have investigated having frames made for them, as I hate how they look. However, all practical considerations (ease of installation / maintenance, cost, not having to have frames made, etc.) point to just replacing like-for-like with a new piece of acrylic.

I don't want to make my life 10x harder than it needs to be for the sake of aesthetic so as a compromise, I thought I'd reach out to see if there are any tips on how to get the most out of surface-mounted windows?

Thank you,
Eddiewo

In case anyone wants to see what I'm working with:

IMG-20250422-185238 hosted at ImgBB
Click to expand...
Fewer screws, but with washers, would IMO also look better, mostly because they would be, form follows function stylee.
 
thinwater said:
An important detail. There are only a few sealants that can stay bonded when hit by UV from the bond side. Sika 295 with the correct opaque primer. Dow 795 (no primer) is probably more popular, certainly in the US. Most sealants, even UV resistant, will fail when the UV hits them right on the bond side. Make sure that your choice is rated for bonding glazing.

Most common sealants will be great for 5-10 years ... and then will start to fail. Sika 295 with primer and Dow 795 are good for the life of the window.
Click to expand...
In Australia we have a local sealant manufacturer - Fixtech, they make a sealant specifically for acrylic windows and bent over backwards when we were replacing ours. I know in the UK people swear by a product CT1 - within the range they might make one for acrylic windows - you need to do a little searching.

Our original windows were fitted using Dow 795, its the same sealant as used to glaze the Petronas Tower in KL. We replaced our acrylic windows because they cracked, after 20 years.

I've heard of Sika 295 but heard no reports - is it newish.

We painted the interior of the overlap, where the sealant is applied, with acrylic black paint. We had no issues but I did ponder that the attachment was to paint, not the acrylic of the windows. I did not mention in the post above - I'm still twitchy (but car windscreens are commonly edge painted (and they tend not to fall out)

You need the recommended thickness as the acrylic expands differentially from the substrate and the coating thickness needs to hold even though the acrylic expands.

Jonathan
 
Martin_J said:
On a previous boat, a Jeanneau Sun Odyssey 29.2, the borders/edges of the acrylic windows were painted silver.

This hid whatever sealant was there from sight, protected the sealant from sunlight/UV (which degrades certain sealants) and to be honest, made the windows look like they were framed..

The silver never seemed to wear off..

Photo example below from the internet..

View attachment 193612
Click to expand...
That's exactly what I did and it turned out well and longevity great.
I bought the aerosol grey paint from Halfords.
 
25 * 3mm stainless strips perhaps
 

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The answer is a method that's easy and simple to do and doesn't leak.

That's probably going to be replacing like for like using new Perspex bedded down on Scapa tape. I'd avoid painting or sticking anything around the border just in case that causes any reaction with paint solvents or adhesive affecting the Perspex.

The Hadlow Marine website is full of useful info.
 
The silver paint (or however the silver colouring is done) is on the outside, so doesn't affect the adhesive properties or the sealant... but yes, if a painted border is attempted, then worth getting a paint that's compatible with the window material.
 
thinwater said:
An important detail. There are only a few sealants that can stay bonded when hit by UV from the bond side. Sika 295 with the correct opaque primer. Dow 795 (no primer) is probably more popular, certainly in the US. Most sealants, even UV resistant, will fail when the UV hits them right on the bond side. Make sure that your choice is rated for bonding glazing.

Most common sealants will be great for 5-10 years ... and then will start to fail. Sika 295 with primer and Dow 795 are good for the life of the window.
Click to expand...
+1 to this. This is why bonded windows have a black edge, to protect the sealant from UV. There was a video done by SV Delos where they visited Rutgerson and this was confirmed.
 
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