HookedOnFishingBoats.com

Are two hulls really better than one?

And you a cat guy, or are you mono-minded? The cat-versus-mono debate has gone on for years, and whichever hull design you favor, the basic argument can be boiled down to this: Powercats usually display superior efficiency and stability, a softer ride and more deck space than a monohull. But, they also look ugly, feel strange when turning, may “snap” roll, plus they cost more than monohull. Which is “better”? Neither, and both—it depends on what’s most important to you as a boater and an angler. But figuring out which one is best for you can be quite a task. Don’t worry: we’re here to help.

Calm Seas

The number one factor that leads people to love cats is their smooth ride. But, is it really smoother? Yup—and it’s been proven numerically. In one cat-versus-mono test I was involved in, we rigged a 26’ Glacier Bay catamaran and a 26 Regulator with accelerometers, which measure the severity of impacts, and then translates the impacts into graph form on a laptop. We ran the two boats side by side in identical conditions, into, with, and across the prevailing seas. Time and time again, the powercat posted drastically reduced impacts. The degree of reduction varied a bit depending on which direction the boat was going (with the most impressive results in a head sea,) but in some cases the cat experienced a mere one-half of the impact of the monohull.

Here’s why: thinner hullforms forward provide less impact area, while narrowing tunnels, called “compression tunnels,” compress air beneath the boat and create a cushion for it to ride on.

Stability is another reason to love twin hulls. Cats are far more stable, which seems like an advantage—and usually it is. But this can be a problem, too. In certain conditions, when the inherent stability of twin hulls is overcome by the seas, the shift from stable to rocking is abrupt and severe. In other words, the monohull rocks a little, then a little more, then a lot. A cat sits stable and solid through the little waves, and then in those a little higher. But when the waves big enough to overcome its stability hit, watch out. The boat will go from an essentially static position into a sudden roll, a motion commonly called a “snap roll”.

Modern powercats also enjoy far superior volume for the LOA. Since the two hulls run parallel to each other all the way from the transom to the stem, the boat enjoys its full beam for its entire length. Take a few deck measurements and you’ll discover that in most cases, this gives cats a 20 to 30-percent deck space advantage when compared to monohulls of the same length.

The final advantage of running a cat is improved efficiency. Remember the comparison between the 26 Glacier Bay and the 26 Regulator? The cat needed just 300 total horsepower to cruise in the mid 30’s and top out in the low 40’s. The Regulator requires another 100 horsepower to post similar performance numbers. And less horses translates into a lower fuel burn.

Mono Power

Of course, there are some down-sides to cats that turn a lot of boaters off. The biggest complaint one hears about powercats is that they look ugly in comparison to monohulls. Fair enough—if that’s all it takes to turn you off to cats, so be it. Another common complaint is that they lean outward in a turn. This feels very strange, especially at first, and takes quite a while to grow used to. For your first season as a cat guy, it’ll feel weird. Then there’s the snap roll which we discussed earlier; which can occasionally cause someone to lose their balance and fall.

Another issue with powercats is their cost. Two hulls require more raw materials than one, and it also takes more time and manpower to build them. As a result powercats usually costs about 20-percent more than monohulls of similar length. Cats over 22 feet long also require twin engines (because turbulence from the tunnel makes it impossible for a center-mounted motor to get a solid bite in the water,) while many monohulls this size perform just fine with one engine. Again, this boosts the boat’s overall cost.

One thing is for sure: if you run a cat like a traditional monohull, and you’ll almost certainly be disappointed by the results because you won’t be enjoying the advantages twin hulls can offer. Often, a test drive with a salesman who doesn’t understand how to properly run a twin-hulled boat turns a potential cat-lover away from the fold. Here’s what you need to know about captaining a cat, to prevent such a thing from happening to you.

TRIMMING is nothing like it is on a monohull. Most cats run most efficiently with a neutral trim, though tucking the bow in just a hair in rough seas can help smooth out the ride. If the boat is “sneezing” (sending puffs of mist out of the tunnel, and soaking the passengers) there’s a good chance you have the motor trimmed in too much. Note that, like monohulls, every boat is different and it’ll take some experimentation to find the best trim setting in different conditions.

TURN slowly, and remember that the outward lean may catch some people off-guard.

TRY speeding up when it’s bumpy. Yep, this sounds crazy, but in many cases a cat’s ride will become smoother as you pack more air between the tunnels.

THIN down the load. Cats are weight-sensitive, and loading them down with gobs of gear can have a detrimental effect on ride quality.

THINK about wake direction when cruising near a lot of boat traffic, because the snap roll almost always happens with boat-generated waves hitting on the hip. Their abnormally even spacing causes one hull to drop as the other gets pushed skyward, but you can avoid this by changing course a hair, so that boat wakes don’t hit dead on the beam.

TWEAK the way you run the boat constantly, and don’t be afraid to experiment. Remember: it’s not a monohull, and what you’re used to doing isn’t necessarily the best way to run this type of boat.

There, now. Try running a cat with these tips in mind, and everything will be just puuuuurfect.