On Fri, Jan 14, 2011 at 09:53:09AM -0600, Lee Huddleston wrote: > > Ben, why did you (and apparently Brent Swain) use stainless steel for the > standpipes?
I can easily inspect or paint my hull when I haul out or dive - but I can't inspect the inside of that pipe... and it would be a) marginally painted as compared to the hull and therefore b) rusting away where I can't see it. In other words, with a mild steel standpipe, I would have an unprotected and uninspectable surface below the waterline - which would therefore rust through one day and sink me. The vessel, though her masts be firm, Beneath her copper bears a worm; Around the cape, across the line, Till fields of ice her course confine; It matters not how smooth the breeze, How shallow or how deep the seas, Whether she bears Manila twine, Or in her hold Madeira wine, Or China teas, or Spanish hides, In port or quarantine she rides; Far from New England's blustering shore, New England's worm her hulk shall bore, And sink her in the Indian seas, Twine, wine, and hides, and China teas. -- Henry David Thoreau I prefer to avoid that kind of worms. :) > I had thought I would just use Schedule 120 steel and design it > so I could clean the pipes as Norm suggested (by running a slightly smaller > diameter pipe through the larger pipe) and coat the insides of the pipes > with antifouling paint using a wad of rags on a line. This is, in fact, how my cockpit drains are done - but I don't trust it. Consider this: my hull is painted with 5 layers of Devoe epoxy and then three layers of antifouling paint. When I rolled all that paint on, it went on nice and thick; I've probably got 1/8"-3/16" of paint on there by the time all is said and done. Pulling a rag through a pipe - i.e., a single layer of paint followed by a wadded piece of cloth that's wiping 99% of it off - can't come even close to matching that. Worse yet, you can't see if you've left any holidays in the paint. Actually, I did the reverse of the usual method: fed a wire down the pipe, attached a rag to it at the top, and pulled it down a bit; then, while having a helper slowly pull it, I poured a whole lot of paint down after it (that way, I had a tall "stack" of liquid paint following the rag - and it wasn't being wiped off.) When the rag got to the bottom, I climbed down, stuck the paint bucket under the pipe, pulled out the rag, and caught (most of) the paint. Then we repeated the drill a couple of hours later, and again later still. Messy, but certainly better than the usual. And I still don't trust it. It's still uninspectable, and I can't tell whether the paint adhered well - or at all. So, the next time I haul out, "Ulysses" gets some new presents: 6" of 2.5" SS pipe both at the hull and on the underside of the cockpit sole, both port and starboard, and some heavy-duty exhaust hose, triple-clamped and cross-connecting them in an X. The SS will not fail, and neither will the wire-reinforced rubber - and I can take a mallet and whack the heck out of the rubber to break any barnacles loose. Besides, it'll be painted with anti-fouling paint inside. Incidentally, now that I think about it - I've had those SS pipes for years now, and have not experienced any problems with draining or clogs, meaning that there's no major obstruction (i.e., barnacle buildup) in there. I wonder why. Maybe they're short enough that everything gets blasted out when I get the hull pressure washed. > I like the idea of a > sea chest, but how does the water get into the chest and how do you stop it > from coming in when you want to work on a seacock? The sea chest is completely open at the bottom. It's a big hole in the hull. :) The trick is that the top comes up above the waterline - no pressure at the top of the box - so you can take the lid off and work on whatever's inside. Like, say, a plastic bag clogging your intake. No diving required. Neat, hey? > Before, I was thinking > of building a screen to cover the ends of the intake pipes. ...but you've figured out why that's not a good idea. :) Yeah, barnacles and "sea vegetables" just _love_ screens. > If, instead, I > build a sea chest, can I simply drill a lot of small holes in the hull under > the sea chest (being careful to regularly make sure the holes are not > stopped up)? The small holes eventually suffer the same fate as screens. A big opening doesn't. > The idea of being able to shut all intake valves with the pull > of one cable was also very interesting. BTW, how can I get onto the steel > boat list you mentioned? It's the 'origamiboats' Yahoo group. Brent is on there all the time, and he's an absolutely brilliant designer who is always willing to give advice on welding, design, ways to think about boatbuilding, and so on. He is perhaps the most valuable resource on steel boats that I've ever found. I once asked him to help me out with a thorny cooling problem, and he essentially designed a system for me and described it in detail in a series of emails. When I asked him what I owed him for this fairly complex piece of work, he said "don't worry about it, but do pass it on." I not only have the highest respect for the man's work - if I had a good partner for this, I'd be building an origami boat in a flash - but I also admire the hell out of him as a person. Incidentally, I strongly recommend his book - "Origami Metal Boatbuilding/A Heretic's Guide" - to anyone who wants to really understand how to think about doing smart and strong boat system design. $25 from Brent, and the ideas in it are worth hundreds of times the price. E.g., he shows you how to build a roller furler system for about $125 that's stronger and more reliable than commercial systems (that's a hallmark of most of Brent's work.) Ditto a windvane for about the same amount. Or a 4700GPD reverse osmosis system for a couple of hundred bucks. His boats have gone around the world using those systems, and they've held up through all sorts of storms. *And* his boats are unbelievably tough, pretty, sail like the wind, and the hull and deck can be built in about a month (he built one and splashed it in 30 days once.) Here's one of his designs, "Silas Crosby", on a blustery day in BC: http://www.youtube.com/watch?v=f_R6U5fxMYA > The > point about being able to boil water in a paper cup and having trouble > welding a tank full of fluid was fascinating. Two points about that: 1) You can't boil water in a thick cardboard or foam cup: they'll burn right up. The trick with the cup relies on the thinness of the paper (i.e., nearly perfect heat transfer with no retention.) Ditto if you focus a point source - say, a torch or probably even a lighter - on a single spot on the cup. And welding is *all* about being a point source. 2) Not only can you weld a tank a full of water, but it's standard practice for welding fuel tanks. Also, underwater welding uses exactly the same standard welding equipment - no magic to it (although they do use a different flux composition on the rods.) I used to have a book some years ago called something like "Own a Steel Boat", by some guy from the UK - Mike-something-or-other. He described buying his first steel boat - very old and rusty. He had to weld up the weeping holes in the hull while sailing it up the Bay of Biscay (!); he'd drive a screw into the hole to plug it up, then tack the head to the hull and work his way around. Sometimes he'd burn through - of course, the metal around the hole would be paper-thin - and then he'd just weld over the leak, or drive another screw if the hole was big enough. The hull must have looked like a hedgehog by the time he was done... :) Ben -- OKOPNIK CONSULTING Custom Computing Solutions For Your Business Expert-led Training | Dynamic, vital websites | Custom programming 443-250-7895 http://okopnik.com http://twitter.com/okopnik _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
