My good friend Darren was in town for a few days this past weekend. Darren and I were close friends in high school, and with my baby sister tagging along the three of us escaped the clutches of small town New Brunswick at about age 21. We drove across Canada in Darren’s car stuffed with all of our worldly possessions, to build a new life in Calgary. We made it, and we never looked back.
Darren and Drew in 2007 or so
I eventually found my niche in the Linux administration world, and Darren settled into a career in the oilfields, one in which he was never really happy. He regularly spoke of quitting his job and moving somewhere warm to pursue a life less ordinary – though as his friends and family heard him say the same things year after year, each time being “just another three months” from quitting, knowing glances began to be exchanged and doubts that he’d ever take the plunge began to grow.
Well, about two years ago he proved us all wrong. After a dozen years in Calgary, Darren quit his job, rented out his house and moved to Thailand to study scuba diving. Since then he’s become a master diver, and has spent the last few months running a diving school on a tiny island in Malaysia. My favourite story from his recent visit was his explaining that just before he left the island he had spent two hours frantically searching for his shoes, which he hadn’t actually seen in two weeks or so.
I had the pleasure of having Darren out to the boat one evening – I would have liked to have him stay a night or two, but I hadn’t quite finished converting the closet back into a berth, and the furnaces are not currently working at the capacity that a visitor from the tropics would find comfortable. His comment, after seeing the boat and hearing about some of the adventures, was along the lines of “Wow, you’ve learned so much in the past year!”. I found that almost funny, considering who it was coming from!
a small selection of the books used on the boat in the past year or so - the rest are packed away...
Regardless, it got me to thinking about the future, and in particular exploring some ideas on what new education I’d like to acquire in the next few months. I think I’m kind of on a roll here for personal development, and well… why stop?
First off, I think I’d like to learn some more sailing skills, in particular I think it’d be pretty cool to know how to use a sextant to navigate. Sure, the GPS has basically made the sextant obsolete – but there’s always the possibility that the GPS won’t work, and there’s something to be said for learning an esoteric skill that requires fancy instruments. Have you seen some of the sextants out there? A cheap plastic “student” sextant actually came as part of the purchase of the boat, and it’d be nice to know how to use it.
Secondly, it seems like a wise idea to pick up a skill or two that I could use to make some money in a pinch, like say if the market for contract Linux IT mercenaries dries up. Ideally it would play off of my natural talents (heh), but even more importantly it should be something useful anywhere in the world. I have two ideas for this – bartender, or sail repair.
tending bar for a crowd of about 3000 dancing lunatics at the Deep End camp at Burning Man 2008
Tending bar is reasonably simple – at least in theory – but the real money comes from being attentive, friendly and social with the customers. I’m a pretty social guy and I seem to be able to get along with most folks, so with a short night course and an exam I could have a bartender’s license, and I could probably parlay that into a position at a vacation resort should I accidentally find myself stuck without cash off the coast of Mexico. I haven’t researched this further yet, but I know that when I spent time tending bar at Burning Man the past few years I had an absolute blast – and modesty aside, I was really good at it. The outgoing, good-spirited social side of tending bar is something that just doesn’t exist in Linux systems administration.
Sail repair is apparently a much sought-after skill in anchorages all over the world – all you need is the knowledge and know-how, and ideally an industrial-grade, manually-operated sewing machine. I’ve heard that if you can sail into a crowded anchorage anywhere, hang your “SAILS REPAIRED” sign from your boom, and you’ll never want for work. I’ve been wondering if there’s a sail loft in town that would be willing to take me on part-time as an apprentice – and for that matter, whether or not I will enjoy the work. If I spend some time learning the ropes it may turn out that I’m not interested in doing it for anyone else, but either way it seems like the sort of skill that might come in very useful someday.
Thirdly, I had wondered about maybe taking a course or two at Langara, especially given that their ‘Continuing Studies‘ program semester starts in mid-January. I poked around a bit on their website, but really didn’t see much that I was interested in. There’s a ‘Performing Arts’ program, but it seems to be exclusively for acting, not for musical performance. I had hoped that their ‘Health and Wellness’ programs might have some first aid courses, ideally of the ‘first responder’ type, but it seems more directed at folks interested in Shiatsu massage. I think I’ll have to look elsewhere to find emergency first aid training.
And lastly, I think it’s time to get back into a martial art. I’ve been skirting around this for years, several times joining a discipline and sticking with it for a few months, then growing bored and dropping it. I think it’s time to start again, and this time around I have my eyes on Krav Maga. My friend Ernst studies this in town, and from everything I’ve read it seems like the best fit. I’m in good physical shape right now, but most of that comes from cycling and rowing; it certainly wouldn’t be a bad thing to vary my routine a bit.
I don’t know where this newfound drive to learn is coming from, but I’m not going to argue with it – nothing bad can come from furthering my education, regardless of what direction I choose to travel. Maybe it’s the winter cold, forcing me into a hibernation mode – or more likely making me want to spend more time away from the boat in a heated classroom. Maybe it’s the dawning realization that I don’t really want to be a sysadmin for the rest of my life.
Or maybe it’s just simple frugality – Benjamin Franklin was once quoted as saying “If a man empties his purse into his head, no one can take it from him“, and I definitely believe this to be true. Spending $400 on the diesel class has already saved me hundreds of dollars that I’d have spent on a mechanic, and I’m sure it will continue to save me money moving forward.
Whatever the cause, I haven’t felt the urge to learn in a while – and I’m going to take advantage of it while I can.
I may not be warm, but at least I have an engine that starts.
Ok seriously, it’s fracking cold out here. The past few days the temperature has dropped further and further, and as I write this it is 6pm, pitch dark outside and -6°C. I know some of you are reading this from the Prairies or the Maritimes, where the ambient temperature has been hovering around -20°C, but I’m going to go ahead and assume that you also have furnaces and insulation and such. Tie Fighter is made of 3/8″ marine-grade plywood over cedar stringers, with an R-value of… god, I have no idea. Not enough, anyway. It’s COLD.
click to view larger - can you spot the outline of the (heated) cabin vs. the outline of the (unheated) closet?
I’ve had some questions posed about insulating the boat, and the short answer is: I’m still researching. One school of thought says that the only way to insulate a wooden boat is to use foam rubber, and bond the foam directly to the wood, being careful not to leave any air gaps between the wood and the foam. The reasoning is that if you leave air gaps, you’re inviting condensation, which to wood means mildew or eventually rot.
The other school says that you should never bond anything to the wood, because that makes it much more difficult to notice problems, and a helluva mess to work with. They say to rather allow it to breathe and stack insulation over top that can have air forced in behind it via fans or blowers, so that the condensation can dry up on its own.
What am I going to do? I have no idea. I’m still soliciting opinions from various liveaboard forums and fellow False Creek denizens. For now, I’m toughing it out and burning several different forms of fossil fuels at the same time trying to stay warm. When I woke up this morning I had to break up the ice in the sink dishes before I could make breakfast.
Cold aside, I HAVE A WORKING ENGINE AGAIN! The diesel engine theory class paid off in spades, and I was able to diagnose the problem, correct the situation, and get Maude started. This was a huge boost to my confidence and self-esteem, especially given the nature of the problem and my previous (complete lack of) experience with engines.
To recap; Maude had started to lose power at some point during my last run up to fill my water tanks. The change was gradual but immediately noticible; the engine dropped in power without my touching the throttle, which is up there with “sounds different” or “emitting smoke” or “smells funny” on the diesel engine scale of uh-ohs. Not quite ‘explosion’, but definitely not good.
The most immediate difference between my response to this problem after having completed the diesel theory class vs. my response before the diesel class is that I now have any response at all other than ignoring the problem and hoping that it will resolve itself. Carrie once said to me “I don’t deal with little problems anymore. Little problems either go away on their own, or they become big problems. I deal with big problems.”. I took this somewhat to heart, but I have come to realize that that philosophy can only apply to some aspects of life; in other situations – diesel engines being a noteworthy example – it’s best to deal with little problems immediately and with extreme prejudice. Don’t just solve problems, smash them out of existence with the largest hammer you can find.
the fuel lift pump, source of my woes
Maude had started to lose power, and I ignored it. The next time I tried to go for water, Maude died about four minutes into the voyage. Fortunately the incoming tide pushed me directly back over my anchoring spot, or I would have had to radio the Coast Guard for assistance. Attempting to restart her seemed to work intermittently, she’d start but die as soon as I applied any throttle, which is exactly the behavior one would expect from water in the fuel lines. The answer there would be to drain the water from the fuel lines, bleed the lines of any newly-introduced air, and then restart the engine – bearing in mind that the “bleed the lines” portion of that answer is an eleven-step procedure requiring three different sizes of wrench.
Needless to say, I was unsuccessful with the bleeding of the lines. For the life of me, I could not seem to get the air out of the lines; I must have pushed that little fuel lift pump lever tens of thousands of times, blistering and scraping my hands in the process. Nothing seemed to work!
Fortunately I had signed up weeks before for the Cooper Boating ‘Advanced Diesel Theory’ class, and so I went to class and paid close attention, asking so many questions that I’m sure the teacher is glad to be rid of me. Each week I returned from class with fresh resolve and a new set of hints, and spent a few hours poking at the engine trying to figure out what part of the bleeding process I was doing wrong. Each week I was unsuccessful.
After five straight weeks trying to perform the relatively simple process of bleeding the lines, I decided that I was doing it right and that there must be something actually wrong with the process. I decided to take each part in turn and track out the problem, just like I’d do with a computer issue. Eventually this led me to a conclusion: the fuel lift pump just wasn’t lifting fuel.
source of the problems, click for closeup
Long story short, I pulled the fuel lift pump off the engine and disassembled it on my kitchen table. I found that the input valve assembly was clogged in the ‘open’ position with a motley assortment of plastic scraps, gelled diesel and hair(?!), which I removed. This was clearly a result of the stock fuel filter having been removed by a previous mechanic and a third-party fuel filter installed instead, after the fuel lift pump instead of before it. I cleaned up the pump, tested and reinstalled it, changing the location of the fuel filter along the way – but still I had no fuel flow!
Finally, after putting together a bit of critical information from the instructor along with a tidbit from the guys at Stem to Stern, I realized that the copper washers in the banjo bolts connecting the fuel lift pump to the fuel lines must be letting air into the lines. I replaced the copper washers, tightened up the banjo bolts, and suddenly fuel began to flow. I performed the rest of the air-bleed procedure, cranked the engine, and low and behold Maude shuddered to life.
Anyhow. I have an engine again, though I haven’t yet installed the secondary fuel filter I purchased, nor replaced the belts, nor replaced the exhaust tank. I have yet to change the oil, either in the engine block or in the transmission. I haven’t even begun to reroute the cooling system, changing it over from raw seawater to antifreeze – but all of these projects will come. I have a working engine, and with a little luck I can keep it that way. I am no longer afraid of Maude. The engine is no longer a black box.
Just to add to the stress of the bitter cold, the police have just motored past in their ‘R.G. McBeath’ policeboat, which is the one they use to enforce the anchoring bylaws – they didn’t stop by to chat, but they’re weaving in around the anchored boats, making their presence known. I don’t have any idea what is going to happen to those of us squatting here in False Creek. I suspect we’ll all be kicked out prior to the Olympics, but I don’t have any good ideas on where to go after that – there really aren’t any other good, sheltered anchorages around Vancouver. The hard winter might shortly become much, much harder.
Nothing much to write about today. The weekend was a whirlwind of activities and too little sleep, and this morning I awoke to bitter cold, howling winds and a dragging anchor – but those sorts of things have become too common, too “baseline” to bother writing about. The winter has arrived, and I’m sure it will get even worse yet, so I’ll save my complaining for the days when things get really bad.
not a regular key in sight
Instead I’ll just talk about my keys; the small collection on a keyring that I keep on me at all times. I hadn’t put any thought into them, but then I noticed a few days ago that my keyring does not contain a single regular-sized key anymore! Every key is a mini-type; my keychain is five keys for padlocks and two keys for bicycle U-locks, and nothing more. It certainly drove home for me the idea that I’ve eschewed the ordinary life – no car keys, no house keys, no office keys. My entire life is secured with padlocks.
My keychain is a small plastic Davis “Key Buoy” keychain that contains a chemical pellet that, when immersed in water (due, say, to someone accidentally dropping their keys into the ocean), dissolves and creates carbon dioxide gas. The gas fills a small plastic balloon which unrolls as it fills, becoming a thin orange inflated tube which then hopefully floats the keys back to the surface.
I used to also have my sailing knife, a Myerchin LightKnife Crew Pro, attached to my keychain – but upon reading the specs for the Key Buoy I think the knife is a bit too heavy for that, and so I removed it and just wear it clipped to my pocket at all times. I love the knife, and recommend it even though the locking mechanism keeps breaking on me. The Myerchin lifetime warrantee covers that though, and they’ve replaced mine for free twice now.
*shrug*. I know keys are nothing exciting, but I figured what the heck, a short post about something trivial trumps no post at all.
Ok, ok. You’re right. I’m slacking and not updating the blog.
I’m not sure what the real reason is. I’ve been maddeningly busy, the kind of busy where it seems like every spare minute is taken up but nothing seems to be getting accomplished. Still, that’s not to say that life halts, and as such I’ve got a whole pile of micro-updates that I probably should have been posting all along. Nothing important or earth-shattering, no crazy adventures, just the usual day-to-day crap. Each of these stories should be its own update though, I just have to stop procrastinating and letting them pile up.
False Creek at night in the rain. admittedly gorgeous. I love my neighborhood.
To start off with, if you’re reading this from somewhere other than Vancouver, British Columbia, you might not realize that it’s been raining for something like fifteen goddamned days in a friggin’ row. I know that complaining about the rain is one of Vancouver’s favourite pastimes, and I knew getting into this that the rain would be something I’d have to face up to sooner or later. It’s not actually all that bad, once you realize that “being stylish” and “being comfortable” are mutually exclusive. I’ve gotten used to living in my tall, bright yellow rubber boots, and leaving the boat without wearing rainpants seems pretty silly these days. Wet clothes hung up to dry can take days to dry on a boat – my sweaters are still damp from laundry day, which was a week ago tomorrow.
The thing about rainpants and raincoats is that they look pretty dorky, but they really work. I have yet to find any that are waterproof, breathable, and look acceptable in public – it seems like you get your choice of any two of those features. I’m willing to pay extra for the good stuff, especially seeing as I use them pretty much every day! I have one set of Helly Hansen raingear that was quite pricy, but it has already paid for itself many times over just through regular use. The other day I caught the pantleg in the chainring of my track bike, pulling it almost the entire way around – but when I unwound myself and pulled it free, the most damage was a bit of chain grease; the rubbery material itself didn’t tear at all.
see the four or five inches of water in there? that's probably a hundred liters overall.
Every day that I go ashore – which isn’t every day, mind you – I have to climb down into my rowboat and bail out the rainwater. I use a plastic bucket made from a cut-off 1.89l bottle of blueberry cocktail, which I assume to be roughly 1l in size, and to stave off the bitter cold and monotony of bailing, I count the buckets as I empty them over the side. My record to date is 120l of water in the rowboat from one night of rain. Seriously! I need to track down and cut up a bleach jug or something similar, bailing at 1l per stroke isn’t the most efficient solution.
One nice thing about my rowboat is that there are large chunks of foam rubber bolted to the inside of the gunwales, which I’m guessing are supposed to keep the boat afloat and upright even if it fills completely with water. This is reassuring – there are a bunch of other boats in False Creek, many of which aren’t liveaboards and the owners don’t come down very often to check on them. Those folks have dinghies locked to the nearby dock, but the rain tends to fill the dinghies up and sink them ever few weeks. Last week, one such boat belonging to my friend Eric had sunk in this manner. When I returned home from a night on the town, I heard strange splintering, cracking noises from the dock as I came down the ramp – it turned out to be Eric’s dinghy, sunken and trapped lengthwise between the heavy wooden dock and the rocky bottom. The tide was almost all the way out, but it still had a foot or so to go… and the noise was Eric’s little fiberglass rowboat, cracking and folding under the massive weight of the dock. Sad, but there was nothing I could do to help.
mmmm, hot cast iron
It has also been cold lately, and as you’ve probably guessed from my last post, I’ve been fighting with my furnaces again. The warmth from a diesel stove is delightful… when it works. I heard someone on another forum describe diesel stoves as “more of a hobby than an appliance”, and that pretty much sums it up. Twitchy things, these machines, and at times it almost feels more like I’m learning to play a new musical instrument than trying to heat a boat. They constantly remind me that they must be treated with respect – as I type this I have yet another slowly-blistering burn on my forearm from touching the wrong part of the oven door while toasting a bagel in the stove an hour or so ago.
When diesel stoves and heaters are working perfectly they’re lovely, but when they start to work badly it’s a slippery slope… give them a bit too much or a bit too little fuel and they’re inefficient, dirty, smelly and can even be dangerous. I’d been feeding the main stove a bit too much fuel, and it responded by filling up with soot. The last time I had an overabundance of soot, I used my little wet/dry shop-vac to clean it out. I was absolutely pleased as punch with the results – until I noticed that every bit of soot that I’d removed from the stove had been blown straight out the back of the shop-vac and all over the cabin, creating a nightmare of a mess to try to clean up. It was literally weeks before I got the last of it – and actually, from where I sit in the aft cabin right now I can see at least two spots where there is still soot from that fiasco.
This time I did not intend to make the same mistake – I researched shop-vacs and soot on the internet, and came to the realization that the root of my problem was simply a lack of a filter device on the shop-vac. Since I could not find any information about my ‘Stinger’ shop-vac on the internet, I made a plan to purchase a newer, more appropriate shop-vac – but when I went to the Home Depot to pick one out, I found that my ‘Stinger’ had merely been renamed to ‘Husky’, and the colours changed. This certainly wasn’t obvious from their website! Fortunately, the Husky model had filters available, and for a whopping $6.99 I left the Home Depot with a filter and a vision of a clean stove.
And it worked! Well, mostly anyway – the stove is now clean and there wasn’t a major mess to clean up afterwards. It still wasn’t a simple or tidy job, and all of my cuticles are still as black as night, but the stove is once again safe and clean-burning. The only real downside is that the filter didn’t seem to get *all* of the soot – I didn’t notice any in the air, but when I blew my nose later on I was startled by a pair of jet-black spots on the tissue. *sigh*.
In other news, I’ve been spending my quieter evenings watching movies I’ve purchased from The Sailing Channel – and actually, I’m really torn here. The Sailing Channel has made their DVD movies available for $29.99 USD plus shipping, or you can download them for $12.99. Wow! That is some seriously forward thinking for a niche video company, and I’m very happy to help support them; I have purchased four downloaded movies so far and will likely purchase more. The part that tears me a little is that for such a forward-thinking company, their website is hideous. Seriously.
One of the movies, Lin and Larry Pardey’s “Get Ready to Cruise“, had a bunch of tips that I’d already figured out on my own, but there were two in particular that were each alone worth the price of the video download. One of the tips involved seat cushions in the salon, which I won’t bother to explain here (yet, perhaps I’ll blog it when I implement it) – but the other was a simple and effective way to build a shower on a sailboat!
9.5 liters of pure, unadulterated cleanliness
I’ve been working a bit on that tip, and while I’ve still got a little ways to go I’m nearing completion. The premise is simple: use a basic pesticide sprayer, and refit it with a longer hose and a showerhead attachment with a simple valve assembly. I’ve expanded on the idea a bit, and replaced the 1/8″ feed tube in the sprayer with a 1/4″ stainless steel version, which should give me significantly more water flow, making it even more like a real shower. I also chose a black plastic canister, which should mean that in summertime I can just fill the canister with water and leave it outside in the sun and in a few hours I’ll have a hot shower. In the meantime, I’ll have to boil a pot of water on the stove, but given that there’s usually a pot of water on the stove for tea anyway, I don’t feel like this is a particular hardship.
After you’ve got the mechanics sorted, all you need is a spot in your boat configured to handle a bit of water splashing around and you’ve got a shower! My boat has just such a place – the bathroom, or ‘head’, right at the front of the boat has waterproofed walls, raised bulkheads and a simple floor to catch the water.
The remaining parts, before I can finally have a shower on the boat, are pretty easy – I need a piece of hose, I need to replace the carpeting in the head with some kind of raised plastic draining tile, I need to fit the bathroom with shower curtains and I need to install a small bilge pump in the bilge to pump out the used shower water. I hope to get those tasks done before the end of the weekend, but we’ll see how it goes.
On the engine front, I think the best money I’ve spent in ages was the $399 for the Cooper Boating ‘Diesel Theory – Advanced 5 Session Program’ course down on Granville Island. The instructor really knows his stuff, and even though the classes come out to about $25/hour, as Trent pointed out a visit from a diesel mechanic is about $120/hour. I’ve learned so much about engines in the past few weeks, and it has given me a great deal of confidence in my ability to tackle any problem that should arise on my boat.
rocket surgery!
That being said, Maude still doesn’t start. I’ve identified the problem; her fuel lift pump is either clogged or the pumping diaphragm has worn out and come apart. It isn’t rocket surgery; I have to remove the pump, disassemble it and inspect it. If it is still serviceable I need to clean it out, then purchase and install a primary fuel filter before the pump ($100-$200), then bleed the air out of the fuel lines, and Maude should then start. If the pump isn’t serviceable (apparently the diaphragm used to be a replaceable part, but they haven’t made them in years) then I have to purchase a new lift pump, which will cost me about $110. I spoke on the phone with Lindsay at ‘Stem To Stern’, the local Yanmar service center, and he was exceptionally friendly and helpful. He was my first contact with that company, and ensured my business – I’ll be heading down to their shop soon to pick up the parts, and I’ll probably also stock up on fuel and oil filters, zincs and replacement hoses while I’m there.
So what’s the holdup? Well, the fuel lift pump is in a very difficult place to reach without pulling out the whole engine, which is simply not an option at this point. None of my sockets are long enough to reach the bolts holding the pump onto the engine, and so yesterday I went to Canadian Tire to purchase a wrench to do exactly that. I figured a single 10mm wrench would do the trick, however when I saw the Mastercraft ratcheting wrenches on sale for $49 for a set of ten, I went for that instead. Comparing that to $16.99 for the single 10mm socket wrench, $50 was a great deal!
there's the problem...
Of course, the wrench doesn’t fit – I mean, the sizing of the socket to the bolt is correct, but the thickness of the wrench itself means that I can’t get it to set on the head of the bolt. I basically need to go back to Canadian Tire tonight to fetch yet another socket – a longer one this time – and then try my best to manoeuvre my hands in between Maude and the wall, remove the pump and then figure out the next step.
Once that’s all done and Maude is starting again, I’m not even close to finishing the other work that she needs. For one, before I purchased Tie Fighter one of the previous owners had had a pump failure while off on a sailing trip, and had to make some emergency repairs – she’s been converted to use raw water (ie straight from the ocean) for cooling. That’s… acceptable, at least according to the manual, but not optimal. There are a pair of heat exchangers bolted to the engine room wall, and a newly-rebuilt freshwater pump is waiting in the wings to be reinstalled. I’m not sure just how much work that will be, but I’m sure it’ll be at least twice as long as my best estimate, which currently is “a Saturday”.
Furthermore, I noticed during one of my extended stays in the engine room that the raw water pump belt is very loose! This is especially troubling, in that it could mean the engine could overheat and eventually fail completely. I won’t have her started up without first replacing that belt. I do have a replacement belt, I just have to install it – thought that means removing all the other belts first in order to get it on.
Lastly – and the most blatantly obvious to any outside observer – none of the instruments work. Nada. Not one. They’re not even hooked up! Neither is the key ignition or the starter switch, none of the gauges or emergency lights… nothing. I basically have to rewire them all individually, which isn’t actually all that difficult, but will take some time. Someone in the past has rewired the panel at least twice, probably due to using the wrong gauge wires originally and having them overheat and melt. I think it’s probably better to just rip it all out and install it fresh, so that I know the work is good from end to end.
Here’s a quick lesson in diesel furnace(*) physics:
(*: or whatever, a wood-burning stove, anything with fire)
The flame in the burner heats up the air, which causes it to rise up the flue and out the chimney. This, combined with the wind passing over the chimney causing a suction effect on the flue, is called “draft”. The draft works in combination with a positive pressure in the cabin, created by a combination of vents, wind traps, and the expansion effect of warmer air vs. colder air. With a balance of positive pressure in the cabin and the draft, all smoke and carbon monoxide exits the cabin through the chimney.
The wind passing over the chimney, the suction effect mentioned above, is similar to blowing over the top of a glass bottle – the flute-like whistling that is made is the air oscillating inside the bottle, unable to equalize because there is no hole in the bottle for fresh air to fill the negative pressure created.
Interestingly, if you were to open, say, a hatch cover in a windstorm, it would be very possible to have this very same suction effect come into play. If that happened, you could easily create a negative pressure within the cabin.
Now – hypothetically speaking – if one were to create a strong negative pressure in the cabin, a few interesting things might happen. Firstly, we can probably assume that because the furnace was running, it must be cold outside – creating the suction effect would probably first suck all of the expanded, rising warm air out the cabin. Secondly, because a negative pressure must be balanced, air would flow in rapidly to fill that void – and as we assume in the first point, that air would probably be cold. Thirdly, that air would have to come from somewhere, and a convenient port of exit (and by definition entry) would be the flue, destroying the draft and creating a backdraft.
The dangerous part of a backdraft is that fuel from the furnace could potentially leave the furnace in an ignited state, and if the backdraft were strong enough, the influx of oxygen could cause an explosive fire. With a diesel furnace however, this is quite unlikely, and what would probably happen is that the flame would be immediately extinguished, leaving the backdraft to fill the cabin with smelly, sooty diesel smoke.
Of course, this hypothetical situation could be easily avoided by simply using the barometric equalizer on the flue, in combination with a draft adjuster below the furnace. One might not leave their warm, cozy bed in a heated cabin to peek outside, only to find oneself having to spend the next forty minutes with all the hatches open expelling smoke from the bedroom cabin and filling the cabin with cold November air. One might not spend the next hour with the foul taste of diesel soot in one’s mouth, or shiver their way back to sleep without the aid of a furnace.
Well, there you have it. A public service, by way of a basic lesson in physics.
Be glad you didn’t have to learn it at 3am in a windstorm.
