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Armchair Horn Sailor
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Discussion Starter #1
I see Lexan marketed for use in deck hatch replacement with a thickness of .118". This seems incredibly thin and flismy to to me for a piece of hardware that could be stepped on. Is this the standard based on the strength of the material or am I looking at the wrong product for this application?
 

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Alden68-

I guess it depends on how big the hatch is. If the port is 3" x 10", like some of the opening ports you see on boats for ventilation purposes, then that might just be okay. If it is for a 23" x 23" hatch, ummm... you're gonna probably step through it.

Size matters when it comes to deck hatch glazing thickness. The larger the opening, the thicker the glazing needs to be. Of course, some hatches have ribs or bars going across them and can get away with slightly lighter glazing materials, but that's an exception.
 

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Alden-
The key word is "marketed". Those guys will try to sell you anything. Like SD says, you've got to run some numbers, the size of the hatch, the loads you expect on it, etc. If the Lexan flexes every time you step on it, it probably will craze eventually. If the purpose is to have the lightest possible hatch glazing that will work for a couple of seasons of racing--it might be fine. If the purpose is to make sure a mast-mounted 20 foot spinnaker pole can't drop through...Maybe not.<G>
 

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Might want to check with the folks at Select Plastics in Norwalk, CT. They do great work at a premium price......and they give free advice! :D
Regards,
Red
 

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Armchair Horn Sailor
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Discussion Starter #5
The hatch has two panels roughly 10 x 21 so they are fairly good size. Definitely not looking for weight reduction as my boat is essentially a sailing cow and I'm sure lexan won't speed her up!

Loewe - I'll look them up....they might be just the ticket.

Thanks.
 

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Given that Lewmar uses 3/8" plexiglass on their ports, which measure 20.5" x 15.375", as seen here. I would suggest that as a minimum thickness for your ports, which are roughly comparable in size.

I hope that helps... :) BTW, that is from their Ocean series of hatches, which I believe are slightly lighter construction than their other hatches. Their Medium profile hatch has a glazing thickness of 1/2".
 

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Glad to help... :D That should give you a good ballpark of how thick a piece of Lexan you'll need. Lexan, IIRC, is a bit stronger than plexiglass or acrylic, so you should be pretty good with 3/8" Lexan... gives you a bit of extra strength. :D
 

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I have 1/2" lexan throughbolted through steel frames on all my fixed ports and 1/4" tempered glass on the opening ports, which will take storm shutters. My forward hatch looks like it came off a tank. 0.118" or less than 1/8th of an inch is a bad joke I wouldn't expect to see on a lake daysailer, never mind a forward hatch. A dropped can of beer from mouth level could conceivably take it out.
 

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Valiente-

Your boat is a tank.. so I'm not surprised... it is a steel boat as I recall... :D
 

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Sailormann said:
Alden - were you looking at the Hunter replacement parts catalogue perchance ???
Ooooh... so mean... funny... but mean... :rolleyes:
 

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sailingdog said:
Valiente-

Your boat is a tank.. so I'm not surprised... it is a steel boat as I recall... :D
Yes, but my '70s racer (the boat I'm loaning out while we cruise) has 1/4" Lexan in the 19 x 19" Atkins and Hoyle fore hatch and 3/8" Lexan drop boards and 1/4" fixed portlights. 1/8" is fine for the glass over my knotmeter, but anywhere else? Not the way I sail.;)
 

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Armchair Horn Sailor
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Discussion Starter #14
Who said anything about dropping a beer? That will get you keel-haued on my boat :) Actually, the spongy core material will probably bounce the can right back into your hand....

West Marine and Defender both carry the .118" lexan marketed as hatch replacement material. Maybe they're in cahoots with Hunter....
 

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I think that material would work nicely for an instrument panel splash guard.. that's about it though... no point on using anything less than 1/4" if the hatch is in a place feet can stand on it... :D

Valiente- 1/4" lexan sounds a bit light for a 19" x 19" hatch, but that's just me...
 

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For years in the yacht repair business I have been replacing the cracked and scratched 1/4" plexiglas in most of the popular 20 x 20 inch deck hatches with tinted 3/8" plexi. At first, I bought raw stock and cut and drilled it myself, but I soon found that I could bring the old piece to a 'GOOD' plastic shop, and they would duplicate it in whatever material at whatever thickness I wanted. It even got so I would send the skeptical customers (those who think you're ripping them off) to the plastic people themselves, then call me when it's time to install it. I never met anyone who wasn't happy to see the thicker stock, but we all felt concern about the ease of scratching. I've heard that Lexan is more resistant to scratching, but is it available in tints? I've never asked and am retired now.
 

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I'm not sure which is more scratch resistant, as both are available with and without scratch-resistant coatings, and it would depend on how the glazing is coated IMHO. They seem to be about the same to me.

The main advantage of Plexiglass over Lexan is its superior UV resistance. Lexan tends to yellow in UV more than Acrylic IIRC. However, for serious use, like voyaging offshore, I would go with polycarbonate over acrylic, due to its superior strength and impact resistance.

Yes, polycarbonate is available in tints, as well as mirrored finishes. Usually only grey and bronze colors though.
 

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Valiente-
"0.118" or less than 1/8th of an inch is a bad joke I wouldn't expect to see on a lake daysailer, never mind a forward hatch. A dropped can of beer from mouth level could conceivably take it out."
Actually? No, I doubt that. You can take a sheet of 1/4" plexiglass and literally beat on it with a baseball bat, and you'll have to mount it very tightly and whale away to break through it. Lexan typically is 10x stronger than plexi (at 7x-8x the cost) so even 1/8" Lexan should take a similar whaling with a baseball bat. You'll probably have to fire that beer can out of a spud cannon, and make sure it is properly frozen first, in order to burst 1/8" Lexan.<G>
Or at least, send someone up the mast to drop it from the masthead!<G>
 

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sailingdog said:
I think that material would work nicely for an instrument panel splash guard.. that's about it though... no point on using anything less than 1/4" if the hatch is in a place feet can stand on it... :D

Valiente- 1/4" lexan sounds a bit light for a 19" x 19" hatch, but that's just me...
It could be 3/8"... and must be as I can stand on it and am a man of some substance.

It's in this family of hatches, anyway: XR Double Frame Cast Offshore Hatch

The new boat has 1/2" acrylic in a similar hatch.
 

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hellosailor said:
Valiente-
"0.118" or less than 1/8th of an inch is a bad joke I wouldn't expect to see on a lake daysailer, never mind a forward hatch. A dropped can of beer from mouth level could conceivably take it out."
Actually? No, I doubt that. You can take a sheet of 1/4" plexiglass and literally beat on it with a baseball bat, and you'll have to mount it very tightly and whale away to break through it. Lexan typically is 10x stronger than plexi (at 7x-8x the cost) so even 1/8" Lexan should take a similar whaling with a baseball bat. You'll probably have to fire that beer can out of a spud cannon, and make sure it is properly frozen first, in order to burst 1/8" Lexan.<G>
Or at least, send someone up the mast to drop it from the masthead!<G>
Sure, I'll concede not many human-powered activities would destroy that hatch, but several tons of sea could. I have seen even Lake Ontario take out fixed portlights set into frames: the fellow in question switched to through-bolted smoked 1/2" Lexan that overlapped the old port. I have also seen a spin shackle in a strong wind crack a foredeck hatch into uselessness. It didn't penetrate, true, but just the whipping action was enough to spiderweb it.

Most of the heavy-weather books I've read have stressed that many current production boats have too large and too weak expanses of plexi/lexan/glass to stand a breaking wave, and that more and smaller portlights, fixed or opening, and provided with appropriate storm shutters, is still the way to go. But it's the rare boat that even has storm shutters, never mind a means to deploy them.
 
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