Stainless Steel: Will it Rust or Won’t It?
Let’s settle this one by calling it “stain-less” steel. Yes, it can rust, but not easily.
This alloy gets its corrosion resistance by having at least 10.5 percent chromium — and up to 18 percent for marine applications. The chromium reacts with oxygen in the air or water to form a thin layer of chromium oxide that protects what is underneath from corroding. Scratch the surface and it immediately heals itself as long as oxygen is available.
The most common staining from this steel is “weeping,” or streaks of rust around a fitting. This means that water has seeped into the fastener’s hole because of poor or no bedding. The water becomes stagnant and oxygen-depleted, the metal corrodes because it is no longer protected by chromium oxide, and rust seeps back out. When you see this, it means that the fastener is failing.
Marine-grade stainless steel also has nickel added to improve corrosion resistance and tensile strength, and the carbon is removed to make it nonmagnetic. Type 304, often used in sinks, is most common and is best above the waterline. Type 316 is better, and 317 (rare) is best.
Adhesives: Should We Trust Them or Fear Them?
The typical reaction to a boat held together by glue is one of mistrust, if not fear — which is just another example of how little knowledge there often is in common knowledge.
An increasing number of major components in our boats is being held together by adhesives, usually methacrylates. Rivets, screws and bolts concentrate mechanical stress loads; adhesives evenly distribute stress.
The most popular of the adhesives is Plexus. Wellcraft was the leader in the use of Plexus back in the mid-1990s with its coastal 26. Today, most builders use it to bond parts such as internal liners, stringer grids and decks to hulls. It’s based on methyl methacrylate, which acts like a solvent to fiberglass laminates. Think of it as welding without heat. The process is called cross-linking, joining the parts chemically and physically at the molecular level. This is in contrast to conventional adhesives such as epoxies, which grip only the surface of cured fiberglass.
So don’t be put off if the boat you’re about to buy is held together with “glue.” If it’s the right kind, you’ll be getting a better product.
Anchors: Is it Size or Weight That Gives Holding Power?
Most folks will tell you it’s all about weight. That’s why we buy anchors by the pound, right? Wrong.
If you depend on weight alone, you’ll need a tremendous amount of it. Let’s say a 2-cubic-foot block of concrete weighs 300 pounds. however, for every cubic foot of volume, an object is buoyed up by 64 pounds when put in salt water. So, our 300-pound block is now doing the job of only 172 pounds. The only hope it has of holding is if one of its edges digs into the bottom. And it’s the concept of “digging in” that led ancient seafarers to make the transition from a killick (a large stone with a rope) to the first anchor with flukes — albeit small ones. This, in turn, has been refined to the high-fluke-to-weight-ratio anchors we have today, such as the plow, Bruce and Fortress.
In the end, it is fluke area, not weight, that determines holding power. The fact that a 40-pound Fortress holds more than a 20-pound model is not because of its weight, but its greater fluke area. The weight is only a byproduct of using more metal.
Diesel Engines: Are They Money Savers or Wasters?
Diesels can save some boaters money, but for most of us, they’re just wasted dollars.
The controversy is based on the fact that diesels use less fuel — a lot less. For example, a 300 bhp diesel might burn 17 gallons per hour when wide open, while a similarly powered gas engine would use about 30 gph. Another saving is that a diesel can typically go 5,000 hours before needing a major overhaul, compared with a gas engine, which might last only 1,500 hours. This is because diesels are made to closer tolerances and built heavier. With proper maintenance, good installation and long, steady running times (rather than a lot of short runs), a diesel can give you a lot for your money. However, while diesels use less fuel, the fuel they use is often more expensive than gas. Diesel averages about 20 cents more per gallon in most states. Diesels also cost more. For example, on a Formula 43 cruiser you’d pay about $55,000 more to get twin 300 bhp diesels over the standard twin 375 hp gas engines. Gasoline engines are also lighter, and less weight means less power needed to get on plane.
So unless you’re fortunate enough to use your boat a lot, as in hundreds of hours per year, diesels turn out to be a waste of money.