Port lite material

[over40pirate]

Just wondering how many other boats out there have glass ports?

My 1973 sloop That I've had for 20 years has glass ports. I believe it's safety glass. It has been 18 years since I rebedded the one that was leaking, and the memory is a litle fuzzy on that point.

After having a few boats with "plastic" ports, then having these, it would be hard to think of anything else. They are still as clear as they were when I bought the boat 20 years ago.

I'm sure the theoretical sailors out there would have something to say about them.
Yeah, yeah, I know if I was sailing to hell and back and the boat was hit by a sunami, etc, etc. I don't drive a tank on the street either! Or wear a helmit when out walking somewhere. Guess I'm living on the edge!


Anyone else have glass on their boat?

[Benjamaphone]

Although I can't speak to the rebedding of your glass ports, "plastic" materials have come a long way in 20 years. Not only are they stronger but they are also much easier to work with and I would imagine that they're also cheaper than safety glass.

[Roy M]

I have just completed a complete reinstall of my fixed ports, all with acrylic plastic, 3/8" thick. Previously, they were 1/4", and held up for over thirty years, and though they had crazed a bit, they were all still structurally sound. I anguished over the same question you asked. I calculated that one glass window (safety laminate) would cost me as much as the entire sheet of acrylic for the whole boat, would weigh four times more, cost six times more, and still not be as strong as the acrylic, would be a nightmare to replace in a foreign port, and wasn't as dark a tint as the bronze acrylic. I didn't want polycarbonate, primarily because it begins to cloud over in about five years, the acrylic remained transparent for its entire life. So, in the end, the decision, for me, was pretty simple and satisfying. I cut the new ports out with a special blade on the sabresaw, filed the edges, then flame-polished with a small torch to remove stresses. I bedded them in 3M 4000 UV, covered with a finishing ring to protect the seal from UV. The screws holding the finishing ring are later removed and filled. Now, I just have to get the cabinsides painted to finish the whole job.

[Benjamaphone]

Roy, those are all great points that your bring up. Acrylic is, in my opinion, the best choice.

And by the way, those fixed ports look great, Nice Job!

[Feetup]

Looks good.
What material did you use for the trim rings?

Tim

[AnchorageGuy]

There are places that will be able to custom make you new glass ports but very very expensive. Do some research on the plastic and you will find it can last for many years if properly cared for.

[Southern Star]

They do look great. As to the original posting, I too am a big fan of tempered glass portlights. In my last boat, I replaced all portlights with cast bronze with tempered glass. In my current cat, the fixed portlights are all tempered glass with aluminum frames. Despite the passage of 14 years since her construction, there is no crazing, distortion or scratches. I was able to solve all leaks by simply re-bedding the original glass.

On the other hand, all of the Lewmar and Moonlight opening hatches/ports on the boat had to be replaced due to extensive crazing to the lenses (and in the case of the Moonlight hatches/ports, broken hardware). The only knock I have on tempered glass is weight, but as for strength, durability and serviceability, there is no contest (ask the Naval Architects who design, and the yards that build ocean liners/cargo vessels/destroyers etc., etc.).

Brad

[mikereed100]

There is some discussion concerning relative merits of glass vs acrylic on this thread.

http://www.cruisersforum.com/forums/...tion-6888.html

When I aquired my current project the windows were made of 1/2" heat formed acrylic and were badly crazed after only 8 years. I imagine the crazing began some time before that. The hatches too were pretty bad. In contrast, La Princessa used to have a Nauticat with tempered glass windows which, despite bearing windshield wipers, were beautifull after 20 years service.

For myself, having a clear view of the world outside through the deckhouse windows rates in priority just ahead of having a working rudder, and for this I believe nothing beats glass in the long haul. It seems that others have had better luck with acrylic. A friend has small acrylic portlights that are beautifull after 17 years. Maybe they used inferior stuff in my boat. Don't know, but I would hate to have to replace again after only a few years.

I will be replacing the acrylic in the hatches with acrylic, but the house will likely have glass. Not saying it's the best for everyone, most cat manufacturers use acrylic or (gasp) polycarbonate, but it's something to consider.

Mike

[Benjamaphone]

Originally Posted by Southern Star

ask the Naval Architects who design, and the yards that build ocean liners/cargo vessels/destroyers etc.

Brad

Brad, its true that tempered glass is better for pilot houses and in areas where you need good visibility or a scratch free surface, however... For these large ships the glass can be 2"-3" thick! For most of our purposes on the cruisers forum, cast acrylic is much more readily available, cheaper, lighter and easier to work with. The original post was about fixed ports where visibility and scratch free isn't tantamount.

Mike, I don't quite know what you mean by heat formed acrylic. Do you mean acrylic that was heated in order to be bent to shape? In any case, a good piece of cast acrylic should not begin crazing until 12-15 years into its life aboard the boat. This is of course assuming that no harsh chemicals (or even some so-called "mild" soaps) were applied. A lot of people don't know that the microscopic etches that soap craves out of a piece of acrylic will lead to accelerated crazing and breakdown.

[Feetup]

I recently purchased some acrylic sheet, and the man who cut it for me warned me that if I used "Windex" to clean it it would craze for sure.
Not sure if this is fact, have not heard it elsewhere, but it could be. He also said a good coating of simonize wax yearly would go a long way toward keeping it clear.
Just for info, I have not been able to verify.

Tim J

[Benjamaphone]

Tim, Windex is definitely a good way to accelerate acrylic crazing. The ammonia leaves tiny little etches that breakdown any of the protection that may be present. I have not tried, and therefore would not personally recommend, using simonize wax. Rather, there are specific acrylic waxes that are made for this purpose.

[Roy M]

Feetup, I built the rims for my fixed ports out of 1/2" Baltic birch plywood, having about 8 layers of void-free birch as the plys. It doesn't really matter what the glue is, since everything was sealed in West System epoxy, then epoxy primer, then (when I finish painting) linear polyurethane paint. The exterior surface of the rim is glassed with 6 oz. fiberglass, as well, to give the surface all the help it can get against abrasion, bashing, UV and general abuse. Since the 3M 4000 sealant is UV stable, the rims may be redundant, but the expansion and contraction of materials could still lead to a leak, so I gave the installation every opportunity I could to make it endure. The last set did quite well. The rims are temporarily held in place by screws, acting as clamps until the sealant cures (I gave it a week). Replacement can be done with a stiff putty knife to remove the rims, a razor knife to cut the interior bead, and patience to extract the acrylic, although you could just cut it out with a sabersaw and pry the remaining pieces. I carry one piece of acrylic, with its protective paper, and the patterns of all the ports scribed and labeled, in case it needs replacement.

[Southern Star]

Ben, the fixed portlights on my cat do not require anything close to the thickness used in the bridge of destroyers etc., because they are much smaller. Further, the fixed bridgedeck portlights in my cat do tend to function as windows in a pilothouse - the navigation station is located there, and with use of a remote for the autopilot, it also becomes an inside steering station. This is not at all uncommon in a cruising cat.

I would also point out that my companionway door is also made out of tempered glass with an aluminum frame. This is also preferable, in my opinion, for the reasons already advanced.

Brad

Brad

[roverhi]

I wouldn't use tempered glass for ports. Tempered glass shatters into small pebbles when it breaks. That would leave you with a gaping hole should an errant shackle or something accidentally break the glass. Could be a fatal problem if it happened in a storm. Safety glass will remain in place because of the plastic center material will hold everything together and be somewhat water tight. FWIW, the saftey glass fixed ports in my boat are going on 40 years old and still quite servicable. There is a little fogging around the edges caused by the plastic and glass delaminating a bit but, overall, they still look awfully good. Imagine plastic would be on it's 2nd or even third replacement by now.

Also, for tempered glass, non tempered glass has to be cut to size then tempered. Once glass is tempered, it cannot be cut as it will pebblize. It's not an operation that any old glass shop can do and probably way more expensive than saftey glass.

[Feetup]

Roy;

Nice work.
I've used Baltic birch for a number of projects, encased in epoxy the same as you. I never dreamed of that application though. You have broadened my horizons.
I agree that the 3M 4000 doesn't need UV protection but it would look so unfinished without the trim rings. They are nice even if only for aesthetic reasons.

Tim J