With catamarans vastly popular in the charter industry, and showing no sign of abating, let's compare the pros and cons of monohull and catamaran strictly on the charter work point of view.
The reason why this distinction is important – and I write this as a monohull fanatic myself - is because for charter companies, catamarans are in huge demand due to the overwhelming number of advantages they offer. Out of charter use, there is no question for me that, when the offshore going gets tough, I would much rather be on a solid monohull than on a catamaran - although the catamaran builders have come a long way to strengthen comstruction. But this is just a matter of opinion!
The cockpit, highlight of catamarans, is usually huge, since it spans over both hulls.
The cockpit and the salon are on the same level, which enhances the feeling of light and spaciousness, along with the typical huge panoramic windows. The foredeck area is very large as well and sports a big pair of nets between the hulls, the notorious trampolines, which make a great sun bathing area. In any case, it is a great observation spot and a kids' favorite.
As a result of this roominess, a catamaran rarely feels crowded, as it is relatively easy to get some seclusion and quietness from other members of the party.
Most cats are equipped with dinghy-davits at the transom, which is absolutely great: no more towing the dinghy, thus no more drag on the boat speed.
The catamaran will provide you with considerably more room than a monohull almost everywhere on the boat: in the cabins and in the salon. Besides, there is ample headroom everywhere. A typical 43/47 ft. cat will have 4 large staterooms, with rectangular queen-size beds – no more of those pointy beds! - each with en-suite bathroom. A 38 to 42ft. will have 3/4 staterooms and 2/3 bathrooms.
Most cats have an enormous salon/cockpit combination capable to entertain about 20 people in style!
Because of the cats’ layout configuration, there is full privacy in every cabin and one does not hear anything from one cabin to the other.
The key fact is that catamarans have a phenomenal stability: they do not heel under way and do not roll at anchor. This usually makes seasickness a non-event. Incidentally, it makes it somewhat safer for kids running around.
Whether at anchor or under way, a catamaran is always much more stable than a monohull. Stability is also a good factor for elderly people and/or first time sailors. As a matter of fact, a catamaran will give the latter an excellent impression for their first cruise, instead of memories of being seasick!
Speed & maneuverability
There is no question that catamarans are faster under power or sail. Whatever your cruising goals are, catamarans will usually move you about more quickly than a monohull.
Catamarans have shallow drafts. This means catamarans can get into places monohulls yachts often cannot reach, and that they can also anchor closer to shore.
However, more and more charter cats now have small "sacrificial" keels to improve close-hauled performance.
Lastly, I personally enjoy the phenomenal maneuverability of the cats. With 2 engines spread apart, you can pivot a cat of any size literally around the boat's central axis – and without the help of the rudders. The autopilot works particularly well on cats, on a tracking standpoint.
A hard-core monohull sailor once said: "When I sail a cat, it feels like I am driving my living room!" He meant that a cat does not convey the "real" feeling of sailing, with the "rail in the water" as sailors say. That is precisely because a cat does not heel, whereas a monohull does, and sometimes a lot. So if you are in for hard, pure sailing, you will not get that felling on a cat. Only a monohull will give you the full experience!
A cat does not typically sail well upwind and needs a different technique for tacking and anchoring. (See tips for cat handling).
It is often said that anchoring a catamaran can be more difficult. This is due to the fact that catamarans have more “windage” than monohulls, and, without keel and ballast, they have a tendency to “bob” on the water when a gust hits.
(See tips for cat anchoring)
Obviously, catamarans take up twice as much docking space as monohulls. This can be a bit of a problem in chartering areas where spending nights in marinas is a necessity.
If you are bringing with you a party of first-time sailors, or older people, or people who could feel apprehensive at sea, you probably will better off with a cat.