Shattered Portlight Glass

[Jeff and Sarah]

Today was one of those rare days in the boat yard where I accomplished everything I had on my list and I didn't need to make a single trip back home or to a parts supply store to pick up a missing tool or part. I got a full coat of bottom paint rolled and two coats of wax applied on the hull along with a few other minor things. No boat day can be 100% without its challenges though! I noticed one of the portlights is shattered. I have no idea how or when this happened. I mentioned it to someone in the yard and he hypothesized a bird dropped something that hit the glass and shattered it. At first that sounded ridiculous- but given that I have no other theory, I'm on the hunt for an inconsiderate bird with impressive aim. I guess I'll start the repair by visiting a local glass shop. Has anyone had to replace your portlight glass before?

[Jim Davis]

No thought on what busted the glass, but I've had good luck with American Glass on Legion Avenue in Annapolis.

[Jeff and Sarah]

Thanks, Jim. I'll give them a call this week.

[Vincent]

Is that safety glass like a car windshield? Would something like Lexan be a better option? If that was a bird, it was doing a pretty impressive strafing run. Kind of like that WW2 movie where the bombers skipped the bombs along the water to hit the dam.
This has me wondering if some Lexan covers would be a good idea for ocean sailing? When we raced my dads boat to Bermuda, any windows of a certain size had to be protected, and we added Lexanto the outside of the large cabin windows. His boat was a Bounty ll

[Frenchy]

At Wikipedia, under spontaneous glass breakage, there are listed several causes for the shattering of tempered glass
including thermal stresses, a hidden defect that grows over time, mounting stresses, etc. I think it's pretty rare.
Tempered glass is strong and doesn't scratch easily. I would replace with what Spartan originally installed. - Jean

[Jim Walsh]

At Wikipedia, under spontaneous glass breakage, there are listed several causes for the shattering of tempered glass
including thermal stresses, a hidden defect that grows over time, mounting stresses, etc. I think it's pretty rare.
Tempered glass is strong and doesn't scratch easily. I would replace with what Spartan originally installed. - Jean

I'm with Jean on this one. Replace it with 1/4" tempered glass. No storm shutters required.

[Steve Laume]

I know from a long ago experience that tempered glass is tough enough to hit on the face with a hammer. No bird wielding clams would be able to break it. That is the good news and it is great stuff. However, even a slight nick to the edge will cause the entire piece to crack and craze just like yours has done. In residential construction the glass rests on little rubber settling blocks to keep this from happening. I am not sure how the edges are protected in our ports but I would take a good look and then replace the glass with another piece, properly bedded in place. You can not improve on the design or materials of those Spartan ports. Those things are bomb proof, Steve.

[Jeff and Sarah]

All good thoughts. I agree with replacing with the same material. It seems like such a strange occurrence! My first thought was some type of temperature issue, but we had such a mild winter that I don't see how any amount of temperature swing would have done it. It's hardly worth worrying about I guess as the glass needs to be fixed with or without discovering the cause. It does still seem watertight- at least through rain storms, so I'm going to leave it be until we have a clear forecast for a few days (which is not this week). Better to have a shattered but sealed portlight than remove it for repair and also have water intrusion!

[Bill Goldsmith]

I've been reading and contributing to the CD Board for over 19 years and this is a new one! A rare occurrence indeed. Any evidence of tampering or vandalism?

[Jeff and Sarah]

I've been reading and contributing to the CD Board for over 19 years and this is a new one! A rare occurrence indeed. Any evidence of tampering or vandalism?

I doubt there was any foul play. The boat yard is very secure as it is on Naval Academy property. It wouldn't be worth the effort to climb on board to break a single pane of glass anyway. It's more of a nuisance than anything and I'll fix it after I launch. I'm already late getting in the water this year because we just had our third child on 4/17 and I didn't get Prereq launched before family came to town.

It is always something!

[gates_cliff]

I've been reading and contributing to the CD Board for over 19 years and this is a new one! A rare occurrence indeed. Any evidence of tampering or vandalism?

I doubt there was any foul play. The boat yard is very secure as it is on Naval Academy property. It wouldn't be worth the effort to climb on board to break a single pane of glass anyway. It's more of a nuisance than anything and I'll fix it after I launch. I'm already late getting in the water this year because we just had our third child on 4/17 and I didn't get Prereq launched before family came to town.

It is always something!

Or, as mentioned earlier, possibly "Fowl play"!!!!!!

sorry, couldn't help myself

[Paul D.]

Congrats on your third child! You are now officially outnumbered and need to move to a zone defense from man to man.

I would agree to replace with the original material. In all my years with Cape Dories I've not seen this one either. Perhaps a call into Spartan would be worth while and maybe find them amenable to sending you a replacement glass?

My guess on the cause, as long as no evidence of impact exists, is the glass was originally cut little oversized or the frame wound up a bit too small and finally some temp change or cradle pressure squeezing the deck structure ever so glacially put it up against the hard edge of the port light frame and "crack". This happens often in auto glass windscreens. My old Camry had some rust on the top of the car just aft the windscreen glass and that pressured the glass just enough to crack it there. The insurance dude replacing it said it will eventually happen again due to the same cause. No warrantee as you might guess.

Good luck,

ps. I have a child's safety harness I sewed up for my kids when they were quite young. It worked rather well as I did several Lake Superior crossings with them when they were 2 - 6 years old. It is made of climbing spec 1" tubular webbing with bomber thread so it probably would not be the weak link in your chain connecting your child to the boat. If you would like it, send me a PM with your address and I'll post it right away.

[Jeff and Sarah]

Paul,
Thanks for the generous offer! I'll send you a PM.
Jeff