There are two schools of thought when it comes to monohull versus catamaran. We have done extensive cruising and lived aboard these vessesl:
We have experienced the good and the bad for both single hull and multihulls first hand. Quite honestly, the plusses for catamarans far outweigh the minuses. There are multiple benefits of catamarans. They are faster, more stable and spacious, and have shallower drafts allowing safer anchorage closer to shore. Being on a stable platform with no heeling cuts down on crew fatigue and seasickness leaving the crew more alert and in control of the vessel. Even novice sailors feel more confident on catamarans.
When we built our monohull "Royal Salute" in the early 90's, catamarans were not established and were looked upon with extreme suspicion by most cruisers, including ourselves. Safety and the "capsize" issue were always the first things to come up against sailing catamarans. It is a fact that monohulls can get rolled in heavy seas but will right themselves because of the heavy lead keel, and while crew and vessel will be battered, the roll is survivable. However a catamaran once capsized, will remain upside down (jokingly referring to this state of the catamaran as "reaching its most stable position when upside down"). The inability of a catamaran to self-right was and still is the major bone of contention. However, what is not often discussed is that a monohull has about a 5000 pound keel of lead that is constantly trying to drag the boat to the bottom of the ocean versus a catamaran that has no ballast and is in most cases with modern catamarans, unsinkable.
So the options are to either sail the world on a boat that, if it springs a leak, will sink like a stone or a vessel that cannot self-right in the event of a capsize but will not sink no matter what. So from a practical point of view, here are our observations over the last 20 years of living aboard, on the advantages and disadvantages of a catamaran.
The speed of a catamaran makes it possible to outrun bad weather. While catamarans do not point as high into the wind as a monohull (or if it does, it makes more leeway or slides sideways), it is about 20% faster than a monohull. That means that even if you sail upwind at a slightly wider angle to the wind than a monohull and having to cover more distance, you will still arrive at your destination long before a monohull. While I believe that catamarans are more comfortable and safer in rough weather, I have to concede that when the weather gets really bad (70 knots of wind or more) I would personally prefer to be on a monohull from a survivability standpoint. I have been in some extreme weather on a number of catamarans and never really felt that we were in danger, although it takes some nifty seamanship. Well designed modern catamarans are very hard to capsize. Having said that, most catamarans can do 200 to 250 miles a day and with modern technology allowing one to pull down weather at will, there is no good reason why you should get caught in extreme weather.
Catamarans rely on beam and buoyancy for stability. Typically cruising catamarans will have a beam to length ratio of roughly 50%, so a 45ft long catamaran will be about 22-ft wide, providing a very stable platform. They are far more stable than monohulls under sail, making sail handling, like reefing or shaking out a reef, much easier and much safer. With a lead ballast for stability and narrow beam, monohulls cannot overcome the rolling and pitching, making the deck a very unsafe place in bad seas.
On all points of sail, a catamaran tracks upright and significantly reduces crew fatigue and seasickness. Seasickness is usually caused by things like anxiety, fatigue, hunger and cold, which all add to a sense of disorientation and leads the crew to making bad decisions and seamanship errors that could be fatal to the crew and vessel. The more stable platform of the catamaran, will hugely keep those issues at bay, making the crew more alert and energized.
During our 15 years of cruising on a monohull, we have often had to leave anchorages that we really were not finished exploring because of a rolly, uncomfortable anchorage. Big rollers or swells coming into an anchorage (like the anchorage in Funchal, on the island of Madeira we were forced to leave in a hurry in our monohull), can make conditions in an anchorage very uncomfortable and unsafe. It could make it untenable to remain anchored, forcing one to go out to sea in foul weather. Catamarans, on the other hand do not roll from gunnel to gunnel like monohulls have a tendency to do and are far more comfortable at anchor.
Catamarans are fitted with a bridle, attached to both bows and down to the anchor chain, resulting in a very stable position at anchor. What we found with our monohull was, that because the bow acts as a sail, the boat tended to sail at anchor in high winds. It sailed in one direction until the chain snatched and tacked over and sailed in the other direction, feeling like it might dislodge the anchor altogether.
Thank goodness we were much younger and more agile during our monohull days. Royal Salute and most monohulls of her generation or older, have high freeboards, making it quite a feat to get onto the boat from the dinghy. It was one of the most challenging things to do because unlike the more modern monohulls that have a scoop at the back, we had to climb up on the side of the boat to get on and off. We, of course rigged steps, etc. but it was always a hassle compared to the ease of getting on and off a catamaran from a dingy or from the water.
Catamarans have significantly shallower drafts allowing for safer anchorages closer to shore. It also allows one to be able to explore areas where the water is shallow without the fear of running aground. The shallow draft also allows for emergency repairs in shallow water and even doing the bottom job when the tide goes out as we have done in places like Mtwapa creek in Kenya, Africa. The catamaran easily rests on her keels on the sand without help making it a breeze to do the "annual haul out".
All catamarans have a set of davits that make it very easy to raise and lower the dingy. Our monohull and many cruising monohulls do not have an efficient or easily accessible set of davits. This makes raising and lowering the dingy a production. The lack of beam and difficulty of lifting the dinghy limits the size and type of dingy that one can reasonably carry on a monohull. As we all know, the dingy is your transport so the bigger and faster the dingy, the better off you are.
We sailed 32,000 NM on our 45 ft monohull, happy as clams, not realizing that sailing does not have to be done lying on your ear 24/7 while on passage or sitting knee-to-knee in the cockpit at anchor with your two other guests at the dinner table. One can liken sitting in a monohull cockpit to sitting in an empty jacuzzi, you are always nice and close to the other folks. Now that we are on our second catamaran, there are a few things that have become very evident. The cockpit and living space in general is huge compared to a monohull, making for very comfortable and spacious living conditions. It feels more like home rather than just camping, however one has to fight the urge to fill the space if you want to keep the cat light and fast. Knowing that one spends at least 90% of one's cruising life at anchor, it's important to have good open living space.
There is very little heeling on a catamaran, so there is no need for handgrips and safety harnesses inside the boat. There is nothing better (and safer) than being able to walk from the cockpit into the living room (saloon) on one level or one step down at most. In a monohull, when heeling at a severe angle, you would have to claw your way from the companionway steps down to the living area, while fighting to stay upright, significantly tapping your energy. Unless you hit extreme conditions, everything stays put on a catamaran reducing the anxiety before doing passages of having to stow and secure everything. This very issue makes a lot of cruisers reluctant to weigh anchor and explore more often. It is just too much effort to pack away all your stuff once comfortable in an anchorage! One thing you will notice is that the stove on catamarans are not gimbaled like it is on monohulls and this should tell the story in itself. The stability and comfort in a catamaran is far superior. Cooking is easy and safer. I often open a nice cold beer, put it down to do something and forget about it only to find a warm beer later in the same place I left it. This is not something that happens on a monohull.
Unlike monohulls, catamarans have a lot of critical redundancies. That of course means two hulls to clean and antifoul, double the engine maintenance, etc. but having two of the critical equipment like engines for instance, outweighs the downside. With two engines, if one fails you still have adequate propulsion to go anywhere. If by some fluke the second engine also fails, you have a full set of spares to fix at least one of them. Our friends once hit a sleeping whale off Tanzania, and when it dove, it hit the prop, bending it. They limped into the narrow channel on the one engine but at least they could make it to a safe harbour where we surveyed and repaired their damage. Because there are two engines there are also two independent charging systems via the alternator on each engine. If one alternator goes out, there is still another complete charging system. There are two rudders and if one fails or falls off (as has happened to our friends on a monohull off Columbia, where they almost lost their boat) you have a second rudder that is completely capable of steering the boat by itself indefinitely.
The engines are spaced far apart on a catamaran and it makes maneuvering much easier and more precise than monohulls, unless the monohulls has a bow thruster. We did not have a bow thruster (not many monohulls do) and had to rely on prop-walk and using prop wash on the rudder. The difference and ease in maneuverability on a catamaran are quite profound comparatively.
Because of the beam on a catamaran the spinnaker pole has become unnecessary equipment. Halleluiah, I say. That pole on our monohull was a pain the behind and I always hated having to use it. On a catamaran, one can fly an asymmetrical cruising chute or spinnaker, using the bows to tack the clew or run a guy through a block so it is very much simplified, easier and safer.
Monohull spreaders are set at 90 degrees to the mast whereas a catamaran has to have backswept spreaders. The reason is that, on a monohull, there is a backstay and using this, plus the intermediates you can get a nice pre-bend in the mast (the pre-bend is to flatten out the main sail and allow for better performance). On a catamaran with no back stay, you need to use the back swept spreaders and the diamonds to pre-bend the mast. The reason I point this out is because on a catamaran, if you want to broad reach or run, the mainsail cannot be let out all the way because the backswept spreader tips could punch holes in the fabric. On a monohull, the spreaders are at 90 degrees so you can let the main and the boom out much further which is, of course, much more effective. This is one of the reasons it is better to broad reach and tack downwind on a catamaran.
It is more difficult to find a dock either as a transient or a permanent slip for a catamaran in general, but this is changing fast and will soon not be too much of an issue. In the USA dockage is charged by the foot so there is no disadvantage there but in some places (the Mediterranean for example) dockage is charged at length times one and a half because of the additional beam. We mostly anchor out though, since the catamaran is stable at anchor, our dinghy is big and comfortable enough to get to shore fast and with the generator and watermaker, docking becomes a non-issue.
It is more difficult to find a travel lift with enough beam for a catamaran for a haul out, while, for a monohull, there are absolutely no problems anywhere.
Catamarans do tend to have a lot more windage than monohulls. This can be an issue especially when maneuvering in close quarters with a strong wind. But I have found that, provided the engines are powerful enough for the size of catamaran, that twin engines negate this problem.
The cost of getting into a catamaran is much higher than that of monohulls. That could put a serious dent in your cruising kitty or require you to put your dream on hold a little longer. However, there are so many good used catamarans on the market nowadays at a much reduced prices than new boats. With a little elbow grease, the used catamaran can be your pride and joy!
So, we have weighed the pros and cons of catamarans and found that the pros far exceed the cons. We made the change to a catamaran and do not regret it one bit! I hope this article will clear things up for all the prospective catamaran owners out there.
Contact us if you have any questions regarding catamarans.