Tuesday, November 2, 2010

Cats are designed to flex: The Oak Tree and the Willow

by Lenny Rudow

Are cat boats really designed to flex like an airplane wing? Sure - in fact, to one degree or another, most modern high-quality boats are. I'm sure you remember the fable about the oak tree and the willow. As the wind blew stronger and stronger, the willow bent over farther and farther. But the oak tree stood firm, and refused to bend. Soon the oak's roots were ripped out of the ground, and it came crashing down. The willow, meanwhile, survived the wind without sustaining any permanent damage. When it calmed down, the willow simply sprang back upright again. Believe it or not, boats are exactly the same way-whether they're built of fiberglass, steel, wood, or any combination of these materials.
A boat that can't or won't flex is one that's full of cracks, breaks, and eventually, will probably suffer catastrophic failure of one sort or another. Stringers break free of the hull, bulkheads get jarred out of position, and cracks radiate from stress points. Why? For the same reason that the willow survived where the oak tree couldn't; a little give and take goes a long way. When a boat crashes into a wave, the impact (lessened, of course, by a cushion of compressed air in the case of most modern cats), sends shock waves from the hull up through the deck, console, cabin, and other parts of the boat. If these parts can't flex enough to absorb that shock, there's only one alternative: something's going to break.
On the other hand of course, too much flex is also a bad thing. It can also lead to massive failure, and commonly creates stress cracking (crazing) in the gel coat, leaky windows and door frames, and stringer or bulkhead separation. A well designed, well built boat-be it a cat or a monohull-will flex just enough but not too much. Luckily, fiberglass as a construction material is quite well suited to flexing. Unlike aluminum and other metals, which tend to fatigue over time, it can flex over and over again and remain resilient. That's why most airplanes, which you can watch flexing in the wings as they taxi down the runway, are “retired” after a specific fatigue-limited life expectancy.
Oil-canning hull or cabin sides, springy decks, and hullsides that visibly flex when a boat moves through the water are all examples of excessive flexing, and if you see them in any boat, you should question its longevity. But on most modern powercats, you're unlikely to see such clear signs of future failure. In fact, you're unlikely to see them on any modern production powerboat; the “new” economy has done an amazingly efficient job of weeding out shoddy boat builders.
Just what amount of flexing is desirable? According to 30-year veteran marine surveyor David H. Pasco, in Hull Design Failure, “there are limits to just how far a designer can go with flexibility. In terms of rigidity, we're talking about the difference of the bottom flexing a quarter inch to half an inch or not at all.” That might not sound like much, but in reality, half an inch of flexing is quite a bit. Remember: if you can visibly see flexing in the boat as you run it, it's probably flexing too much. So the next time you run a powercat, watch the hullsides closely and see if you can notice any flexing. Chances are you won't. But trust us, there is some give and take in that fiberglass. Just enough-but not too much.


A well built cat will flex just the right amount. Note how these high-stress areas on this Glacier Bay haven't cracked at all, despite years of hard use.

Monday, October 4, 2010

A properly-operated cat will remain more level and straight when running then many monohulls

by Lenny Rudow

Cat Advantage 9: Cats are easy to learn to drive


Get into an outboard-powered monohull of your choice, trim the engine(s) all the way down, and run fast into a following or a head sea. You’ll find that in most cases the bow digs in and shoves the boat off-kilter as it strikes the waves, because full trim is too much trim. The engine is forcing the bow down, even as it enters the water and buoyancy naturally forces it up. There's only one thing it can do - go off to one side or the other. An inexperienced boater may simply think the boat's design is flawed, but improper trim is the problem, and improper trim is usually the reason why a power cat might slew off in an odd direction, too.


Run a powercat with the incorrect trim, and it'll act just as weirdly as a monohull would. Unfortunately, few inexperienced boaters think to adjust the trim regularly and as a result, are left with the impression that the cat they're riding, and maybe all cats, act strangely because of a design problem. Not so.


The key thing to remember here is that some cats are very trim-sensitive (others aren't to the same degree) and a competent operator will constantly adjust the trim to match conditions. In most cases it's a good idea to start off with the trim set at neutral, and make minor tweaks up or down until the most comfortable position is reached.


Often, weight distribution plays a role in this problem as well. When everyone aboard is on one side of the boat, causing a notable list, the hull on that side of the boat will dig in more than the other. Naturally, this causes the boat to angle off in the direction of the excessively submerged hull when it strikes waves. Alleviating this problem is easy: trim the opposite hull's engine down, and the over-weighted hull's engine up. This will return the boat to a level riding position, and end the angles.
Even with all four anglers hooked up and fighting fish from the same side of the boat, 
static stability on this Glacier Bay 22 is far better then the norm.

One oddball we need to mention: The Glacier Bay 22 tends to wobble back and forth from port to starboard, particularly in a beam sea, even though static stability is far better than it is on most boats. As far as I can tell this is unique to the model (I own one myself) but it can be alleviated by mounting the motors on a small inward angle, and adding hydrofoils to the lower units. New models ship from the factory set up properly, so usually this is an issue with older boats that were dealer-rigged. And IMHO, it's a small price to pay to have one of the smoothest-running hulls in the world underfoot. The motion is gentle, predictable, and something you get used to after running the boat for a while, anyway. Problematic? No--just different.

Remember that many cats are weight-sensitive forward of the helm, and that this symptom can be exacerbated if you add a lot of weight to the bow. The bottom line is that you want the two hulls riding evenly through the water. Forcing them to do otherwise can create undesirable riding characteristics, for sure--just as it would do with a monohull, or any other type of boat on the water. But if you take the time and effort to run the boat properly, cats don't exhibit these problems any more or less then monos. In fact, in many cases a properly-operated cat will remain more level and straight when running then many monohulls, particularly wide-beam deep-V's with lots of deadrise, which often tend to shoot off in one direction or another when climbing the back of a wave in following seas. Which is "worse" when you take these issues into account? That's a call every individual has to make on his or her own. Just remember that all boats have their plusses and minuses, and those minuses will be made worse if the boat's not being run properly. That can lead to rumors like this one--rumors that aren’t accurate, in the least.
Yup, she's still sitting level with us all on one side

Friday, October 1, 2010

Cats eat rough seas for breakfast

by Lenny Rudow

Cat Advantage #10: Cats are very stable in rough seas

How do ridiculous rumors get started? We all remember that lesson in school, where everyone made a circle and whispered a sentence into the ear of the person next to them. By the time it made it all the way around the room, that sentence bore little resemblance to the original one. Well, the same thing happens in real life. An example: As a die-hard cat fan (and owner) I was disturbed to hear that someone had flipped an 18' Nautico powercat in the Ocean City inlet. So I did some investigation, and eventually confirmed that it was true. Yes, it happened--in the middle of the night, while the boat was being operated by a drunk captain, and an opposing current and 25-knot winds had created six to eight foot waves. Now, you can't find an 18' boat on the face of the planet which wouldn't have been at risk of flipping in this situation. Yet somehow, news of this event was taken by many (mono hull dealers, anyway), as evidence that cats flip in rough seas.

I've logged about 3,000 hours in powercats ranging in size from 18' to 26', and have encountered plenty of nasty seas and several summer squalls with intense wind. But I have yet to worry about flipping over in one. In fact, if anything the enhanced stability of a cat makes it less likely to flip than a monohull, not more likely. And as a general rule of thumb, the fact that a
powercat is significantly more stable than a monohull of the same approximate size and weight isn't in dispute--not even by monohull salesmen and builders.

Of course, we haven't even discussed the fact that all cats are different anyway, just as all monohulls are different. Would someone assert that all monohulls are bumpy, because they rode through a tight chop in one that had a flat bottom? Of course not. All cats are unique too, and to lump a displacement cat like Glacier Bay's 26 Canyon Runner in with a semi-displacement cat like a World Cat is patently ridiculous. Nor have we addressed the fact that most powerboats which flip do so after being swamped--not while they're running through the seas.

Maybe you've heard this rumor yourself, and maybe it even came from a relatively reliable source. So don't take my word for it. Google "powercat boat flip," and see what you come up with. You'll see some people who repeat the rumor without citing any source or event as evidence, but you won't find any Coast Guard figures, studies, or even reliable articles or design papers that back it up. And that's because the flipping cat rumor is just that--a rumor. And if you own a cat, as long as you don't go running through an incredibly rough inlet at night while drunk, in all likelihood the only thing that'll be flipping is the fish in your cooler.

Will it ever flip? Not likely - the enhanced stability of a cat is one reason why I bought a Cat

Cat Boats Drive Beautifully in a Following Sea

By Dean Travis Clark of Sport Fishing Magazine

Cat Advantage 1: Cats track well in a following sea

Just like in a mono-hull if you trim the bow down this causes more resistance on the bow and can cause it to be more difficult to steer in a following sea. But if you trim the bow up, the boat will go up and over the following sea and it will drive beautifully. The following video shows the advantage.

Monday, August 30, 2010

Selling cats is no harder than selling a popular monohull

by Lenny Rudow


Cat Advantage 12: Strong resale value


If you're shopping for a new boat, one thing you might hear is that old cats have a low resale value. Someone might tell you the market for cat trade-ins is poor, and you'll have trouble moving a used cat. But if you've a savvy shopper, it might occur to you to check out the book value on used cats as opposed to used monohulls. You might check the NADA listings, and discover that a 2005 26' Glacier Bay Canyon Runner or a World Cat 250 has an average resale value that sits right in-between a 25' Grady-White and a 26' Sailfish. That sounds mighty strange for a boat that doesn't have a good resale value, doesn't it?


Here's the real scoop on re-selling a cat: it's no different than selling any other used boat. It may take a while to sell and you will have to find the right buyer, but believe me, he'll be out there. Want an example? When I sold my 2002 19' cat, in 2008--during the recession and one of the worst boat markets in memory, mind you--it took about five months. I ended up accepting a little over half of the boat's original "new" selling price. Considering that the boat was in good cosmetic shape but had about 600 hours on the engine, this is a perfectly acceptable, normal, common, average re-sale. And considering the state of the economy when it was sold, it's rather amazing that it didn't take even longer to sell. There were other people interested in the boat when it sold, and after the transaction was complete I had several other people get in touch with me. About half of them were extremely familiar with the specific model. And this leads us to an interesting little quirk about cats that sometimes makes them even easier to re-sell than your average monohull: people that experience them become dedicated fans.


The phenomenon is similar to that seen with a handful of classic monohulls, like the Bertram 31 or the Grady-White 208 Adventure. These boats were a tremendous success in their time, were copied by numerous builders, and have a following that has near cult-like dedication. The same is true, in a broader sense, of cats. When an experienced cat owner goes looking for a new mid-sized center console, he's likely to whittle down the field to two or three models--say, that Glacier Bay Canyon Runner or World Cat 250—and focus on them with an intensity. A monohull owner, on the other hand, is likely to go looking at a zillion different model 24' to 27' center consoles, until he finds one that fits. Here's another example I can give you first-hand: when I wanted to up-size from the 19' I knew I wanted a 22' Glacier Bay, period. I looked at a half a dozen hulls before finding the one that I thought was priced right and in the proper condition, and pulled the trigger in short order.


The bottom line? None of us buy boats as "investments," we buy them because we want to use them. But at the same time, we don't want to make a ruinous decision. Lucky for us, this isn't likely to be a problem, for a cat owner.
Some cats have cult-like followings, and selling them is no harder then selling popular monohulls.

Wednesday, August 4, 2010

Power Cats are a beautiful traditional boat...especially in 6' seas

by Lenny Rudow

Cat Advantage 2: Modern cats have shearlines like a traditional boat
Should form follow function, or vice-versa? How you answer this question probably determines whether or not you'd ever consider owning a powercat. Do they look different then monohulls? Of course they do, with very few exceptions. And if this is more important to you then a smooth ride, high efficiency, enhanced stability, and all the other benefits that go along with running a cat, all one can say is "I hope you enjoy your monohull, which will look great even if it beats you to a pulp."


Before we get too carried away with how silly this entire argument is in the first place, let's remember that monohulls aren't all "lookers" either. There's a heck of a difference between the visual appeal of a traditional Maine lobster boat, a modern center console, and a southern skimmer, for example. But you won’t hear a northern guy whine that his boat isn’t sleek-looking enough, nor will the offshore angler turn down a CC because of the swishy Euro-transom, nor will the die-hard shallow water redfish angler complain that his skimmer looks boxy. So, why all the beefing about the different looks of a cat? Because it’s an easy argument to make. It's no different than politicians slinging ad hominem mud. When a boat salesman has a potential customer in the showroom, criticizing the competing boat's looks takes no effort or logic, and scores easy points.


Again, it all comes down to what is important to you, as a boater. If looks are the number one concern, then you may well be turned off by many cats (though I would note that personally, I think Glacier Bay's 27 and World Cat’s new 32 are a couple of the hottest looking boats on the water). If performance or seakeeping are the most important factors, you’ll have no problem getting past the "different" look of a cat. Instead of a squared bow, you’ll see additional forward deck space and stowage areas. Instead of a boxy cabin, you'll see boosted interior volume. Instead of an unusual hullform, you’ll see a smooth ride and easy trailer loading. As with many things in life, what looks good is more a matter of how you see things, then it is of what you see.
Do you see "squared" or do you see "roomy"? This cat is only 22' LOA.

Tuesday, June 1, 2010

Most Times I Prefer a Cat

by Lenny Rudow

Cat Advantage 7: Experienced boaters prefer cats

In offshore powerboat racing, where catamarans go faster than V-hulls with equal amounts of power, EXPERIENCED BOATERS PREFER CATS. Or, in the ferry industry, where virtually all new high speed ferries are catamarans, EXPERIENCED BOATERS PREFER CATS.

I hate to sound like I'm tooting my own horn but I've been on boats since I was two years old; I've owned boats since I was a teenager; I tested boats for Boating Magazine for well over a decade and in doing so sea trialed literally thousands of fishing boats between 12' and 80'. So I think I can comfortably place myself in the category of "experienced" boaters. And yes, I personally prefer cats in many circumstances. Maybe even most.
The author has put over 200 hours of running time on 14 different models of powercats, including all of those pictured here. Does that count as "experienced?" We'll let you decide!
The bottom line is that I have a bad back, thanks to all those years of bouncing around on boats. Most of them were monohulls, and I've felt the bam-slap-crack of a fiberglass smacking a wave at high speed countless times. In 1996 I had my first full season with a cat, an 18' Nautico "project" boat which we used as a test-bed for new products and systems being reviewed by the magazine. Amazed at how little that boat hurt my back, I ran another cat project boat through the seasons of 1997 and 1998, all the while still spending plenty of time on monohulls both for Boating and on my own personal boat. In '99, it was back to a monohull. And in 2000 I bought a new boat of my own—my first cat. When we were boat shopping, at one point I told my wife I didn't think I'd even own a monohull again. I was wrong: I have two today for waterfowling, which monohulls are better for, thanks to a multitude of reasons like load bearing capabilities, construction materials, and design. But when it comes to boats between 18' and 35' used for fishing in open waters, when it comes to running through rough seas, when it comes to drift fishing, when it comes to trolling the canyons, when it come to dockside handling, when it comes to getting a single multi-purpose boat in this size range, this is one experienced boater who prefers catamarans to monohulls-period.