Catamaran 101 Q&A

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Catamaran 101 Q&A–New to catamarans? Some answers

How Fast Are They?

They do 10, 12, 15, 20 knots! Is this what you’ve heard from salesmen at the boat show? The truth is, a well-designed catamaran behaves much like a light displacement monohull. With many delivery trips under our belt, I can confidently say that, on average, on a passage with winds from a variety of points you will average passage speeds about 20% greater than a similar-sized, cruising monohull. Having said this, here are some best cases: We have averaged over 14 on a Fountaine Pajot 35 for a 6 hour period going to Newport‐off‐shore. The Fountaine Pajot 42, recently delivered transatlantic, rode the front edge of the most recent hurricane with 30-knot winds and averaged almost 16 for 24 hours! (Because storms normally move at 10‐12 knots, a fast catamaran has the capability to run away from them‐an an important safety feature!)

Why Do The So-Called Ocean Going Cats Have Such High Freeboard?

In the Ocean, you need bridge deck clearance. That is, the height of the center part of the boat between the hulls must be as high as possible to avoid wave pounding. Wave pounding on a lesser boat, at the least, prohibits sleeping on overnight passages (Ever try sleeping inside a drum being pounded on?), at the worst, we’ve seen lesser boats where the bulkheads have literally been knocked loose. Also, the blending shape of the underbody is important. Rounded connections and smooth transitions soften wave action much like a shock absorber.

Will A Cat Go To Windward?

Today’s modern, well-designed Cat, with fin keels, will point about as high as a comparable, good cruising, monohull. They readily tack through 90 degrees without any need to backwind the jib. Having said this, if you point as high as a monohull, your speed will also be about like a monohull. The great increases and better VMG’s are achieved by footing off a bit. Get a good set of polars. Experiment. You will gain a 20% advantage overall and as much as 50% or more on a reach!

Why Won’t Anyone Recommend A Furling Mainsail

A cat is very dependent on a large roach. A fully battened, full‐shaped mainsail works best. The jib serves more as a foil to direct the airflow (consequently you don’t need a large jib.) This makes the boat easy to sail and tack, and very powerful. This type of sail would need to be excessively flattened and compromised to make it possible to furl it in the mast boom.

Why Do Some Cats have Center Pods?

(An extra hull that literally dips in the water.) This is a capitulation. If overall construction is too heavy, the beam is too narrow, and/or the bows are too heavy a center pod is necessary to give adequate buoyancy and interior volume. No serious Ocean going Cat is designed with this feature. Look at the world’s best!

Isn’t The Load Carrying Capability Of A Cat Less Than a Mono Hull?

Yes. If you overload a Cat performance will be reduced to that of a comparably sized monohull ( however, you still have a bright open saloon, privacy in the sleeping areas, shoal draft and all of the other advantages of a Cat.) With today’s modern equipment, however, you can keep the weight down when planning long periods aboard. Water‐makers reduce the need to carry large water tanks. Lightweight generators, air conditioning with air‐handlers, and other types of modern equipment allow you to bring comfort along, without excess weight.

What About Safety?

I sail/sell both monohulls and catamarans. Both have pros and cons, but all things considered, I think the scales tip in favor of catamarans. The main reason I say this is that the most likely problem at sea for either type is not capsizing, but rather running into debris or a whale that punches a hole in a hull. A 6″ gash in a monohull has been known to sink it, literally within seconds! The same gash in a Cat would limit water intrusion to one of several watertight compartments. Not only wouldn’t you sink, but you could also continue sailing to a repair yard! More serious damage might stop you, but your unsinkable cat would be an easy find for rescuers after you set off your EPIRB.

One bottom-line test? We have boats delivered trans‐Atlantic regularly. Generally, Insurance costs the same or less for cats. That’s a valid statistical measure of risk.

What About Turning Over?

An ocean-going cat, well designed, with a 50% (or greater) beam to length ratio, is unlikely to turn over. These boats are designed with static stability in excess of 60 knots.

What’s static stability? A simple measure developed by highway sign builders of what wind speed it would take (based on surface area) to blow a roadside sign over. On a Cat, this is a simple measure but gives some idea of the enormous stability. A Cat with a 60-knot static stability factor would actually have a much higher factor in a dynamic situation. A 60-knot puff would actually cause the boat to slide sideways. Some of the force would be translated into forwarding motion. This would probably increase the dynamic factor to over 100 knots. If you were unobservant enough to have the full sail up in such conditions, the rig would probably break (like having a fuse in an electrical system) before the boat would capsize!

So why do you see pictures of upside down multihulls? Simple. If a monohull flips and fills with water the evidence sinks and the occupants are either never heard from again, or are located in a tiny life raft. A turtle, still floating racing Cat makes a great photo opportunity!

In the ocean with storm conditions, you must slow the boat down. If you don’t, the boat will surf faster than the wave system and literally plunge into a wavefront, tripping the boat and causing it to flip over‐not capsize. In storm waves, a prudent skipper, on cruising cat where safety rather than speed is the priority, will reduce sail and, if necessary, employ a drogue. Racers, on the other hand, are pushing the limits and sometimes flip. Then, because of the unsinkable characteristic, there is a great photo opportunity when the rescuers arrive seeing a lone sailor standing in the inverted multi hull waving at them. Of course, the cat racer is much better off with access (through the reentry hatches) to his food, water, stores, and safety equipment, and with a huge platform for the rescuers to find! NOTE: I like to compare this situation to your car leaving the 65mph expressway and entering a 25 mph exit ramp. Sure, you can push to maybe even 40 (depending on the ramp and your car!) but at some point, exiting at too high a speed will cause your car to lose control and possibly rollover. The same thing with cats if you’re not prudent enough‐‐just as you are in your car‐‐to slowdown!

If I Have Mono Hull Experience, Will I Be Able To Handle A Cat

The best way for me to answer is to explain how we handle 100’s of clients who have monohull experience and want to charter a Cat. In this case, we find that if they have had experience on a similar-sized monohull, they can get the hang of it with about an hour special instruction. If their experience is on the light side, we suggest a captain for the first day.

What’s the primary difference that you have to learn? Under power, handling twin engines. It’s actually easier, but you have to learn to maneuver with just the throttle/shift levers and not the rudder! You can actually make the boat turn in place, and go sideways once you get the hang of it. No more panic backing or maneuvering into tight slips!

The second issue is a little better understanding of the sailing principal of VMG. That is, in a Cat, your Velocity Made Good to windward is better when you don’t point up as high. You sail a little further, but a lot faster and get there faster than a comparable monohull.

Finally on the issue of safety. With a cat, you virtually can’t capsize with wind alone (See Good cat/Bad Cat for more on static stability), and because there is virtually no heel as the wind increases (you simply go faster and faster…) you eventually overpower the boat with the risk of some weak link in the rigging letting go‐‐an expensive lesson! For our charterers, we ask that you sail by the numbers. That is, We tell you the times to put in the first reef (about 18‐20K of apparent wind) the second (about 28‐30K.), etc. We provide wind speed instruments which provide wind speed capability, and make sure that you know how to use them!

When you purchase a new or used Cat from us, your BYA broker or one of our captains will be happy to spend a day or more with you to make you comfortable in this new world of catamaran sailing!

Isn’t It Hard To Find Dockage?

This was, perhaps, one of our biggest surprises when we started getting involved with Cats. What we found was that when you’re a transient (going up and down the coast or cruising long distance) you generally are offered a berth on the outside of “T” docks‐‐no problem with cats here. (By the way, we have also found that the prices for transient cats are the same per foot cost as for monohulls!)

In many cases, the easiest thing to do is to take a mooring or anchor out. Your Cat is such a stable platform that it doesn’t rock and roll with wakes or surge. The ventilation is excellent in a more open area (away from a closed-in marina) as most serious cats are specifically targeted for sailing in tropical areas so their ventilation is extremely well thought out. Finally, dinghy davits with the dinghy nestled securely between the hulls allow for a large, hard-bottomed dinghy (water taxi) making it easy to move back and forth to shore.

If you do need to be in a marina we’ve found a couple of common themes. New marinas often have large slips or alongside tie-ups for large powerboats that also work for cats. Many marinas have space up near the bulkhead that is gradually being filled in by erosion. Often you see small powerboats docked here. We have had excellent success placing catamarans, with their shoal draft, in these spaces‐‐often for lower rates than normal slips!

Finally, (maybe this is unique to the Chesapeake) we find that many older marinas have slips designed 20 years ago when 40′ monohulls had 9′ beams. Today’s 12, 13, and 14′ beams just won’t fit. We’ve been able to have yards pull center pilings and create larger slips that can accommodate cats or larger monohulls.

All and all, this just hasn’t been the problem we thought it would be, and, to date, no owner that we sold a cat to has had a problem.

How Big A Boat Do I Need To Do A Transatlantic?

(Or another offshore cruise.) Generally, if the boat meets all of the best of the criteria described here, 35′ is about the minimum size for a transatlantic. Why do I say this? Because every year we deliver several boats transatlantic, as well as many more from the East Coast to the Caribbean. The captains who do this all the time, tell us a well designed 35 (like the Fountaine Pajot Tobago) is the smallest boat they will even consider.

As the boat gets larger, two elements come into play. Longer waterlines make for a more comfortable motion more nearly matching the wave period of ocean waves and, the load-carrying ability increases.

We’ve all heard of small (some under 10′!) boats, unprepared boats, and even outright dangerous boats making successful crossings‐‐ but here I’m talking about comfort and safety for real-world sailors who are not just performing a stunt.

So can you sum up the differences with Catamarans compared to monohulls? Sure, here they are in a nutshell…


Catamarans average about 20% greater passage-making speeds when we compare deliveries from the Chesapeake to the Virgin Islands in a variety of conditions..

Load Carrying

Figure approximately 10‐15% less load carrying ability‐‐size for size compared to monohulls. Our custom computer program can help determine your new boats’ capability and considers each piece of equipment you add. Our engineers will design the systems to match your requirements. For instance, we might specify a water‐maker for passage making, rather than increasing the size of water tanks. (A side benefit is that the water doesn’t get stagnant when you’re only week ending.)

Boats like the Fountaine Pajot, designed primarily for private owners (About 80% go to private owners) have more volume in the hull, and generally have much higher load-carrying capacity than boats designed primarily for charter.

Keel Choices… 101

Construction of a fin keelIn general, for a cruising cat, you have the choice of fixed keels or daggerboards. There are pluses and minuses to each choice, but in general, the nod goes to fixed keels, especially if they’re constructed like the Fountaine Pajot “break-away design.  By molding the keels and gluing them into a socket, if you hit something and break one-off, there is no water entry into the boat (like there is if they’re molded integrally), and the boat will actually sail acceptably well with one keel.

Note. If you’re used to monohull keel concepts, the catamaran keel is not used at all for stability, (Stability comes from the buoyancy of the hulls, widely spaced for leverage) …they’re only used to sail to windward. The keel is, generally filled with foam. So the Fountaine Pajot approach to keel design makes the most sense for serious cruisers.

Other advantages of keels, vs dagger-boards for serious cruisers. Much shallower draft-with two keels (especially compared to monohulls), so you have the lateral resistance without needing such deep draft. The boat will rest on its keels with no further support for bottom painting, service, — or at the beach. Good low-speed maneuverability and straight-line tracking. They’re simple and easy.

The problems with dagger-boards. Because the foils are so thin, and surface area is so minimal, they have poor, low-speed maneuverability–like when docking, for instance. While they can offer slightly better windward performance, this is only true when you’re paying 100% attention. Talking to guests, or having a beer–anything that distracts the helmsman creates a situation where the boat actually loses it’s advantages and actually does worse. The same is true when you’re under autopilot which steers an average, rather than an attentive course. Finally, they’re more complicated. The trunk takes up the interior room. They cost more. They’re, relatively, fragile. If you pull the boat up on a beach, gavel (but also barnacles grow in the well) so the board often gets stuck and, at the end of the day, you see many dagger-board cruisers sailing the whole season with their relatively fragile dagger-boards stuck in some in-between position. If you’re a performance aficionado, consider this choice, otherwise, go the way that 90+% of cruisers go with normally fixed keels. The FP approach is an even better choice than most.

Useful Volume

Cats have about the volume of an 8-10′ larger monohull. I.E. a 38′ Cat has the room and accommodations of a 48′ Monohull. (A handy fact when planning a Cat charter!)

Price and size. Interestingly, when we devise a formula for calculating volume, the prices for comparable volume monohulls and catamarans are about the same, but when you look at the cost per foot, the catamaran costs more.

Bottom line: You will get the equivalent of an 8-10′ larger monohull in a given sized catamaran. The bonus is that the cat has redundant systems, engines, etc. for better reliability and flexibility in actual service. I.E. You can run with one engine. You can even run with one keel–they are sacrificial–if you break one off on a reef, no water comes into the boat–see the keel discussion.


Price per pound is higher, the price per Cubic Foot is lower. (The construction is higher-tech, and the vessel’s surface area is greater contributing to a higher cost per foot. )—but then you knew that, right?


I’ll leave that to you. They grow on you.


The Cat wins hands down. Lighter, airier, more upright sailing. The motion is different and takes some getting used to, but we’ve found people that get queasy below on a monohull underway, are perfectly fine on a Cat after a few hours of adjustment.


A cat is much better under power. Under sail, they handle similar to a light displacement monohull. That is, you need to carve your way through a turn, rather than throw the helm over. Once you get the hang of it, you’ll be able to tack as easily with a cat as a monohull right on down to the lightest of air. (You do have another decision to make though. To take crab/lobster pots to port, starboard, or between the hulls!)


Similar but different. Most owners really like the invincibility aspect. Both types are safe when they are good representatives of the designers/builders art, and when handled by prudent, experienced skippers. Catamarans turn over about as often as monohulls sink. However, in almost every case the cats that turned over (and whose crew(s) were picked up) were racing and pushing the envelope where the monohull cruisers might have just as well been cruising.

Safety bottom line? We deliver both monohulls and catamarans trans-Atlantic from France to the U.S. East coast–regularly. The insurance costs for cats is the same or less than for a monohull–so the insurance tables seem to think they’re at least equal.

Other important facts that improve the safety of catamarans.

  • Built to Category A, offshore standards including with re-entry hatches on appropriately sized models.
  • They don’t sink, and serve as an easily located platform is disabled.
  • They have crash partitions (for serious offshore cats) that limit the extent of damage and water entry should a submerged object be hit.
  • They have redundant systems, especially 2 engines and 2 keels, so they can keep going if one of these becomes disabled.
  • They average about 20% greater passage speeds when comparing loaded boats, to monohulls. When the wind is up like if you’re running ahead of a serious storm, they exceed hull speeds and can easily do 10-12 knots. This is in the range of how fast storms move, so with good weather information, you can turn at right angles to a storm track and get out of harm’s way.
  • They are much less tiring to sail, because of the lack of heeling–so the crew is not so tired and stays more alert.

The Bottom Line

I hope that these ideas have helped you to have a better understanding. Nothing beats getting out and experiencing the sailing first hand, and that’s why we offer such a large selection in our charter fleet. If you’re just out for a vacation, try one. If you’re thinking of owning, our Try‐Before‐You‐Buy program provides you an opportunity to sail for up to 3 days for free if you later decide to purchase. In either case, our club program provides equity towards the purchase when you use it to charter from our participating fleets.

A well sailed cat can make an excellent choice for a live‐aboard or serious cruiser if you choose wisely and keep the ideas presented here in mind.

Eric Smith

Senior Sales Consultant, Partner
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