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September 21, 2007

Anchors That Work Better


Mighty Mite's grapnel design with re-bendable tines is handy for anchoring on wrecks and rock piles.

An anchor. It looks like a dead-simple piece of metal, but it plays a vital role in the life of any boater. That's one reason engineers can't resist tinkering with them. The basic, time-proven designs are still with us, of course, but somehow people keep managing to come up with better ways to keep a boat from drifting off.

Anchors come in a finite number of styles; they either hold a boat by weight, by hook or by burying themselves. Some, like the Navy anchor - the kind you see on the bow of battleships - use weight and flukes together, but they have limited use in recreational boating. Same with the traditional kedge, the kind Popeye has tattooed on his forearm. This is a difficult-to-store antique - effective, but clumsy. There are some spin-off designs that can be especially handy on grassy bottoms, as their single arms can pass easily through thick vegetation, which can be a challenge for other types of anchors.

The Versatile Danforth

Probably the most widely used anchor on fishing boats is the Danforth, which features a pair of hinged flukes that lie flat on the sea bottom and dig in under pull. The Danforth lies flat in the anchor locker, is lightweight and has a high weight-to-load ratio. It's a proven, all-round design, but still not perfect. Consequently, it has undergone some tweaking over the years, and minor though they might seem, there are big differences in the details.

In 1986, Don Hallerberg, a boater and engineer, brought the lightweight Fortress anchor to market. Today, Fortress is perhaps the best-known brand of Danforth-style anchor. Featuring adjustable flukes, the Fortress is machined from aluminum to make it very light and durable (there are no welds to break). Another benefit is its versatility. The standard angle on the flukes of a Danforth is 30 to 32 degrees, optimal for most conditions. However, in soft, muddy bottoms, a steeper angle makes for quicker, more secure sets. For these conditions, the Fortress's adjustable flukes can be set at 45 degrees.

Anchors That Work Better
Fortress's retooled Danforth style is lighter than ever, but features sharper flukes to grab bottom and hold on.

The aluminum construction of the Fortess also allows for sharper flukes than are normally found on a galvanized Danforth anchor, according to Dan Sheehan, marketing director for Fortress. Sharp flukes allow the anchor to grab the bottom more easily and dig in faster than other, heavier models.

While that's all well and good, the real advantage of the Fortress, from a boater's standpoint, is weight, or lack thereof. Aluminum is a lot lighter than iron, which makes the Fortress easy to handle and deploy, especially in the larger sizes. That it retains all the other advantages that have made the Danforth such an overwhelming favorite among recreational boaters is almost a bonus.

The Grapnel

Despite its advantages, there are things you don't want to do with a Fortress anchor, such as drop it into a big, jagged wreck on the bottom. Not unless you just like buying anchors. For dirty work like this, you need something a little more suitable, and the grapnel anchor fills the bill.

The grapnel is a variation of the kedge design, a hook-style anchor. Originally, the popular fisherman's grapnel was little more than a bundle of metal rebar welded together for half its length, with the free ends bent to form hooks, or tines. The concept is that the tines can be straightened under power to free the anchor if it becomes snagged, and later bent back to their original shape, time and time again. This is the anchor to drop into a mess of a wreck or a big, grabby rock pile.

But even the lowly grapnel hasn't been safe from innovators. Case in point: Ken Chaumont's Mighty Mite."The guy I bought the design from was an old sea captain, and he was so tight that he didn't want to lose his homemade grapnels," says Chaumont. "So he built one out of aluminum conduit, epoxied lead inside the shaft, welded on the rebar and came up with a small, heavy wreck anchor that was easy to retrieve."

While Chaumont's anchor will hold in any bottom, he acknowledges that it is a specialized anchor. "It's a niche anchor," he says. "Its niche is wrecks and jetties."

Niche anchors aside, it's important to have a primary hook that works on a lot of bottom types. As mentioned, one of the more versatile types is the Danforth. Another is the plow.

Plow Improvements

Anchors That Work Better
Anchor Concepts' HydroBubble takes the plow anchor to the next level; its float ensures that it lands the right way every time.

Also called the CQR - as in "secure," the name given it by the inventor - the plow style is widely regarded as one of the most versatile anchor designs. It holds well and releases easily in a variety of bottom types. It's an especially popular design on larger boats, simply because it's relatively bulky and heavy, but can be tough to stow when space is limited. Both the Bruce anchor and the Delta are refinements of the original CQR design, with slight modifications. All have earned a place at sea.

The plow works like this: Once it lands on the bottom, usually on its side, it needs to be pulled into the upright position to dig in and bury itself. This slight disadvantage was the inspiration behind the newest brand of plow-style anchor: the HydroBubble.

John Willis, designer of the HydroBubble and president of Anchor Concepts, was often frustrated when trying to set a traditional anchor. He wanted something that would land upright and set itself on the first try, but he was also partial to the plow design. And he's an engineer.

"I felt the plow was the most sensible device," he explains, "because it's designed to dig into the earth - as a plow does in agriculture. So we worked out the angles and things like the area and the displacement on the computer to get the best combination of those aspects."

What he came up with is a two-piece design with a flotation pod on top. The plow blade is a single piece of stainless steel with a removable aluminum shank, which makes the anchor light and easy to stow. A single shackle holds the parts together to make assembly and breakdown easy. Once assembled, the shank has a little bit of side-to-side play, reminiscent of the swivel on the original plow design, which allows the blade to stay buried even when the boat swings in the wind or current.

The big difference between this anchor and its predecessors is the way it lands on the bottom. The HydroBubble lands upright thanks to the float on its shank, which causes the anchor to descend blade-first and land upright. Once it hits bottom, the slightest tug on the rode causes it to dig in.

The stainless blade of the Hydro-Bubble is especially small, which allows it to dig in more easily. It also maximizes the weight per square inch that's in contact with the bottom. Combined, these details make for a sure, fast set.

"I have yet to have anyone tell me they threw the anchor into anything like normal conditions and not have it set straight away," says Willis. "With any pressure at all, it immediately cuts in. It has to. That's the way it's designed."

How critical is this characteristic? It can be very important in a crowded anchorage, or when positioning yourself over a small wreck or rock pile where precision placement is paramount. Or maybe you just don't want to fool around trying to get an anchor to grab.

None of us are going to carry several anchors to meet all conditions, and nobody has yet come up with a single design that does everything perfectly. But as long as there are tinkerers in the world, and engineers, we'll never be wanting for innovation - or an anchor that does just a little bit better job.