Replacing US 30 Port Windows

The two opening ports- one above the map table in the V-berth and the one in the head were pretty much on their last legs. So I measured them, thinking this will be easy, since ports are pretty much standard sizes. Right? Wrong. I couldn’t find any to fit. So tonight, as I remeasured AGAIN, Brian asked, “Are the sizes somewhere on the port?” Nope, but there was a manufacturer name! Beckson. I Googled them and found their site.

The exact ports I was looking for happened to be there- and on sale for $40 each- what excellent luck! After tax, shipping, and a tube of silicone caulk, the total was $104. Way cheaper than anyplace else,

and actual direct replacements for what we already have (this means no having to cut new holes!)

Here is the site: http://www.beckson.com

Chris

The Truth about stainless steel

Lately I’ve been reading a lot of information about stainless steel on the various sailboat related web sites, and I am surprised at the amount of misinformation and in some cases downright garbage that has been posted on the subject.
I make my living specifying grades of stainless, testing stainless, designing in stainless, and certifying products, including ASME code pressure vessels, made from stainless. As a young man I studied engineering, a great deal of which involved the science of metallurgy. For many years I made a living on the shop floor working with metals, but especially stainless steel.
That being said, I am NOT a metallurgist, nor would I consider myself an expert on it’s properties and use. I would say, however that I have gained a working knowledge of a very complex subject.

Stainless steel is just what it’s name implies. It is a steel that stains less. It is not impervious to corrosion, it can rust, and in the right conditions it will corrode away to nothing.
Stainless is mostly iron. It has been given a good resistance to corrosion by the addition of alloying elements, most notably chromium and nickel. The chromium also adds to the strength of the product. There are other elements added as well, in very precise amounts, and these elements, and the quantities thereof determine the grade of stainless, and of course it’s characteristics.
What gives stainless steel it’s anti corrosion properties is a very thin layer of chromium oxide which forms on the surface of the metal almost immediately after it is exposed to oxygen. It is the same thing that keeps the chrome bumpers on that classic Jaguar looking like a mirror. The crystalline structure of the common grades of stainless is described as “face centered cubic crystal” or FCC which tells us that each grain of the alloy is roughly cube shaped, and the boundaries between the cubes contain the majority of the alloying elements, especially the chromium. Such alloys are called Austenitic after a metallurgist named Austen. The 300 series stainless steels fall into this category.
The most common grade of stainless steel is 304, or 304L which has a lower carbon content for ease of welding. It contains 18 to 20% chromium and 8 to 12% nickel along with traces of other elements. It is also known as 18-8 grade for obvious reasons. It is quite strong, cannot be heat treated to enhance hardness but will harden on it’s own if worked, by bending, forming, stamping, or by continued cyclic loadings which cause even a moderate change in shape. This is known as work hardening, and along with the hardness unfortunately comes brittleness. This is why things that are heavily cold worked like swaged terminals on standing rigging have earned a bad reputation. If they were over swaged to begin with, and they are installed in such a way that they are forced to flex, they WILL crack some time.
The problem with 304/L stainless with respect to sailboats is the fact that many of them are sailed in salt water, and salt contains chlorides. Now chromium is a marvelous element, but one of the few things it cannot stand is chloride ions. Stagnant salt water is rich in chloride ions, and unfortunately low in oxygen, the element necessary for the production of the chromium oxide layer that protects the metal. The chloride ions take away the very thin layers of chromium that surround the crystal structure, leaving the iron at the mercy of the elements. It usually does this in one of a few predictable ways, which give characteristic names to the type of corrosion. Pitting corrosion is as it sounds, a number of tiny pits that trap stagnant water with it’s chloride ions causing it to self aggravate. I have seen situations in industrial applications where a small pit on the surface was really the opening to a large cavity under the surface. Stress corrosion cracking is a fancy way to describe a type of pitting corrosion where the pits follow lines of stress, linking together to form what appears to be a crack that follows the stress lines. It will follow built in stress lines, such as where the metal has been formed or bent, and it will also follow the stress caused by continuous strain. such as in the root of a large agitator paddle. The third kind of corrosion is called crevice corrosion, and this happens where a crevice is formed by the nature of the devise, such as between a keel bolt and the hull, or between the swage and the wire of a terminal. It is basically pitting corrosion caused by the proximity of the parts, preventing an easy flow of oxygen, and promoting standing chlorides.
The bright minds of the last century were not unaware of these problems and worked hard to solve them. One of the better solutions was to decrease the chromium content, increase the nickel content and add 2-3% molybdenum. This gave the alloy much greater resistance to chlorides, iodides and halides and only reduced it’s strength by a very small amount. They called it 316, or in lower carbon form, 316L. Also known as 16-10 stainless. It is only a little more expensive than 304, and other than ultimate strength and cost surpasses 304 in almost every way. It is even a little less susceptible to work hardening. For anything outside of the cabin, this is the alloy to specify. Even inside it is a good choice. There are many alloys that are better yet, but the price premium is not worth the performance advantage for normal humans. Some of these alloys sell wholesale for over $50 a pound.
So what can we do to protect the stainless we have? On our old boats much of it will be 304L, at least above the waterline. there are a number of things, all aimed at not giving the chlorides a chance to work.
1 Keep it clean. Rinse it down whenever you can with fresh water. I keep a small pressurized garden sprayer on board to rinse down when I can’t get to a hose.
2 Protect it. a wipe with an oily cloth, or a spray with one of the many protectants will do wonders. Sure it keeps the oxygen away, but it also keeps the chlorides away too. There is a product called “Fluid Film” that is mostly lanolin which works marvelously in the presence of salt water. Great for the engine compartment and electrical as well. A word here though. don’t spray a rust penetrant or oily film onto the lower terminals of the running rigging unless they are dry. You could conceivably trap salt water in the swage, making things worse.
3 Shine it. Not only does it look fast, it polishes out the tiny pits that give a place for the nastiness to begin work.

Stainless is great, it just isn’t a miracle, and most of the disappointment with stainless comes from the use of the lesser grades. You get what you pay for.

Tim

Key West Attempt

Here’s a short video of our attempt to make Key West from Tampa (MacDill AFB Marina). We hit a high-pressure system followed by back-to-back cold fronts and the seas got nasty. We made it as far as Port Charlotte FL before we turned back (we were making slow progress and breaking a wave over the bow every 8-10 seconds) because the weather forecast wasn’t good for the next 7-10 days. After that we tool a leisurely two days to motor back up the ICW. There was something like 16 draw bridges and 3 fixed on the way back. We didn’t get any footage of the bad weather because it was at night and we were tired. Apr 2008. When we got to our home marina, we slid her back in the slip and drove down to Key West for 6 days

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