# Light coming through fiberglass



## labestia (Dec 24, 2008)

Recently when evaluating a sailboat for purchase I noticed that when inside the forward cabin there was light visible coming through the fiberglass on the ceiling angle to the port side. It doesn’t seem that any damage or repairs have been done to the area. Should this be of concern?


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## merc2dogs (Jun 5, 2004)

It's pretty common on boats without a liner or nothing on the inside, Most likely the gel coat or paint is thin on the boat.

I wouldn't say it was anything to be concerned with.

The gel coat on my old portager 22 had a few scratches and scuffs, but was in overall decent shape when I got it, but after pulling the carpet out of the interior it 'glowed' inside, so I decided to go ahead and paint it.

if the exterior is nice, you can paint the interior if it bothers you.

Ken.

EDIT: Many boat builders used the translucent characteristics of fiberglass to provide light, cape cod marlin for one a few pics shown in the thread here:

The Plastic Classic Forum :: View topic - Cape Cod Marlin

It actually depends on the boat itself as to whether it's unusual, some companies went thin on the gel coat intentionally , so it's 100% normal, others went with a thick layer of gel, so seeing light would be unusual. it does not mean that the boat is bad, it is either normal for that boat, or just means that a PO may have sanded out some minor scratches on the gel coat. 
Gel coat is often applied with a spray gun, so it's normal to see a wide variation even on the same boat.

Ken.


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## NOLAsailing (Sep 10, 2006)

Nope - it's normal. Fiberglass is translucent and you often see what you're describing anywhere the paint or gelcoat is off or very thin. It can be a little disconcerting though!


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## ahab211 (Jan 6, 2008)

If you are interested get a survey. There was not enough glass laid down or it wore away. Either is a bad sign.


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## sailingdog (Mar 19, 2006)

Most boats aren't technically sprayed with gelcoat, as that is usually done for repairs... the gelcoat is sprayed into a mold, and the fiberglass laid up over the gelcoat, inside the mold. Gelcoat that is too thick tends to crack and craze as it doesn't flex as much as the underlying fiberglass. 

Fiberglass is normally fairly translucent, unless it is very thick or cored.


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## boatpoker (Jul 21, 2008)

Gelcoat should be about 22 thousands of an inch thick. The resin is translucent as are the glass fibers ...... no problem !


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## Coreyboy18 (Jun 2, 2008)

Well I am certainly glad I stumbled on this thread. While in my Ranger 23 the other day, I pulled the front locker in the v-berth and noticed one little area where light was glowing through the hull. It scared me. I went outside to look at the front of the hull and no sign of repair or anything. So I asked a friend and he said it was normal on the Rangers of that time, and other boats too and nothing to be concerned with. Glad to see this thread to further substantiate that claim.


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## SOUNDBOUNDER (Dec 16, 2008)

I have seen that even on a new Grand Banks. In the engine room, you could see light coming through the side of the hull.


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## Faster (Sep 13, 2005)

This is particularly noticable when the side of the boat you're looking at is in direct sunlight.. On a solid-skinned (uncored) boat with white/light gel coat it's of no concern - as many have already indicated.


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## sahara (Dec 15, 2006)

It's actually probably better if the laminate is translucent - especially below the waterline. Some people think that pigments added to the resin may exacerbate blistering.


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## NOLAsailing (Sep 10, 2006)

ahab211 said:


> If you are interested get a survey. There was not enough glass laid down or it wore away. Either is a bad sign.


WHAT???


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## eMKay (Aug 18, 2007)

NOLAsailing said:


> WHAT???


Don't listen to him, people need to learn not to post when they do not know what they are talking about, it just makes things worse.

Anyway, yeah, normal. Mt Siren was like that, My O'day however has grey gelcoat and I have not noticed it.


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## MarthaT (Jan 13, 2009)

NOLAsailing said:


> WHAT???


wow


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## kaluvic (Jan 14, 2009)

Even with a very heavy lay-up over 3/4" you will see light.
I've often thought it's an opportunity for manufacturers to lighten the interiors by having outside areas with clear finishes instead of paint or gel coat.


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## Cruisingdad (Jul 21, 2006)

It is when you see light from THE BOTTOM of the hull there is a problem!!!! 

(HEHE!)

- CD


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## TSOJOURNER (Dec 16, 1999)

*"see-thru" hull*

Thank you all for your comments; they educated and relieved me as I found this site when searching for answers to the concern I had after inspecting, and before buying, a '79 Catalina 27 where I could see a bluish/green translucent light shining thru the hull fore of the head holding tank area. This won't be my first sailboat, nor, do I suspect, will it be my last!


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