Yesterday I received an e-mail from a friend who reads the blog, very politely asking if, with all these thoughts of drogues and junk rig, and sailing far enough out to make these things relevant, WHAT ABOUT THE WINDOWS?? He was much more delicate than that…
It is not, indeed, that I have neglected to think about this! Here is what I have learned, over time, and my process on the subject:
The windows are, almost for sure, made of Lexan. That’s the trade name; the actual material is polycarbonate. This is a lot stronger than Plexiglas (acrylic), and Plexiglas is a whole lot stronger than glass. A small test to confirm that the windows are actually polycarbonate has been in the works for a while – because just like my friend, I do indeed have concerns about the window issue. This test will likely be happening on Tuesday when Theo is here. (For information on determining the identity of plastic, see here: http://www.consultekusa.com/plasticidentificationchart.html ) The bottom line is, if you burn it, Plexiglas smells fruity, and Lexan smells like phenol, which is the smell of hot electronics, more or less. If you burn a known sample for comparison, it’s better – last week we got a piece of factory-labeled Lexan from the hardware store, and are looking forward to trying it out. We’ll be shaving a little curl off one of the boat windows to burn, for comparison to a curl off of the Lexan from the store, and then to a curl from a piece of Plexiglas. Ten minutes of high entertainment, getting to play with fire!
Earlier in my thinking about the window question, I was considering storm boards – plywood inserts to cover the windows in case of being caught out in a serious storm. I have been told by two different boat designers that with windows of this size made of a reasonable thickness of Lexan – 1/4 inch in this case – storm boards are really not necessary. One of the boat designers said, “to demonstrate this to yourself, you could take a hammer…” Seeing the look of alarm on my face, as I contemplated anybody taking a hammer to one of the windows of the boat, she said something about using a sample of Lexan in a frame. But the whole suggestion did make the point. She was quite confident that the result of such a test would be completely reassuring.
Another individual, who designs sailboats with large windows, said roughly the same thing, as far as the strength of Lexan, and talked about commercial fishing boats in Southeast Alaska. Those boats have windows bigger than AUKLET’s, and work in a region where fast-developing storms often have winds of hurricane force. Some of the folks up there laugh that farther south, storms like the ones that they have routinely are here given names… Their boat windows are frequently made of glass, and still, waves smashing out windows is not the problem that you hear about. A couple of friends who sail up that way, and whose boat has Lexan windows larger and closer to the water than AUKLET’s, have indeed had no problem (knock wood!) in many years of Southeast Alaska sailing, williwaws and all.
And then here, in the Northeast, there are all the powerboat folks, commercial and recreational, some of whom are out in very wild weather, with large-area windows. Actually, none of this serves to make me feel completely, totally relaxed about it – but it has done quite a bit to calm my concerns. Writing this does make me think that it would be interesting to get a piece of known Lexan, put it in a frame, and invite folks to take a sledgehammer to it. Like after seeing the video of a family going to great effort to capsize a Peep Hen (which required an adult hanging on the end of the mast to do it, and when finally achieved, the boat floated high on its side, taking on almost no water, and none through the open companionway) I would probably feel a lot better after watching Lexan stand up to the test. Maybe we could make a video, and post it here!
My friend who wrote yesterday also mentioned the concern of the large deck house – another issue that has also given me pause. Because, following the general rule, the best oceangoing sailboats have low deck houses to go with their tiny portholes. The boat designers I’ve talked with have been unconcerned about this as well, referring to both the sturdy construction in AUKLET, with the sides of the deck house extending down into the interior of the boat, as well as to the curved shape of the deck house (in plan view as well as the crowned top) and the small size of the boat. The small size of the boat has the effect of making it overall far sturdier than larger boats that are built with the same half-inch plywood materials. From an engineering perspective, it is my understanding that the small size advantage also draws on the same physics as the strength of an eggshell, having to do with the curves relative to the size of the object – eggshell or boat. At any rate, it was comforting to hear their perspectives.
Where deck house size and height really do make a significant difference is in upwind sailing ability. AUKLET is really the design of a “motor sailer,” in spite of the fact that I am using the boat primarily motorless. For beautiful upwind sailing you want much less wind resistance on deck, like so many of the lovely traditional sailboat designs. I should also note that the Glasshouse Chebacco does indeed sail upwind – not as perfectly as it might with a lower deck house, but making headway against both wind and seas. And does that with my less than perfect upwind rig… The difference is mainly noticeable sailing alongside elegant traditional Maine racers, who pass by in two tacks out of a harbor, when it takes me a few more. Still, the trade-off with the Glasshouse Chebacco is fine with me: giving up some upwind sailing ability, in exchange for comfort, interior light, solar heating, and good visibility for sailing from within the cabin, all feel well worth the exchange. With some extra time, and attention to working with the weather (along with staying well away from lee shores), regardless of the upwind abilities issue you can still sail quite a ways!
I know that there are stories out there about deck house failure, and window failure, in heavy seas. I am curious as to details, and my process of picking up relevant information is ongoing. In the meantime, the arguments that have been made by folks who are way more knowledgeable than myself, about both the windows and the deck house on AUKLET being up to the task, have felt like enough to make me feel okay about proceeding with this boat, including somewhat offshore.
However, it does remain an intriguing question. If evidence comes along that this should be rethought, I will most certainly be doing that, and adjusting plans accordingly. WRC, thanks for the question!
Some people have all the fun.
Polycarbonate Window Impact Testing 001:
Thanks! That’s a great video. Pretty encouraging about acrylic, too. We still haven’t gotten to do our burn test (reassembling the tabernacle did seem like a higher priority :-) but with this information in hand, and getting to watch that bowling ball bounce, even if our windows are acrylic it doesn’t seem so bad for now. Still contemplating the sledgehammer fun, just to see it for ourselves…