Monohull or Catamaran
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Monohull or Catamaran?
Here are the facts!
best suits you
We have been
selling both for over 30 years. We've delivered them coastwise and
offshore. Chartered them. Lived-aboard for extended periods and had a
chance to talk to designers, builders delivery captains, owners and
management company owners. Here's what we've found...
Eric Smith, President
Monohull vs Catamaran?
Who do you trust? The
boating press? They have obligations to their advertisers. Did you ever see a bad boat
review? Your friendly Boat Broker/Dealer? Why do their positions seem so aligned with
their products? They sell Catamarans only? Theyre the best. They sell monohulls
only? Theyre the best. How about your friend whose heard things. But who
has sailed monohulls for the last 20 years. He can certainly tell you about those
We sell and sail both
Catamarans and Monohulls. We run charter companies featuring both. We hire captains who
deliver both. Visit factories for both. Talk to designers for both.
This presentation will
be based on our experiences with both types of boats. We
sell both about equally and have
little to gain promoting one over the other. In addition to our personal experiences, I
will relate what were told by transatlantic delivery captains. By owners and charterers. By designers. I firmly believe that when something is
right, it makes perfect sense. I hope that you will find that this discussion makes sense.
In the end, you have to decide what makes sense.
In this presentation,
Im talking strictly about boats that make sense for living aboard and offshore
sailing. Not daysailors. Not racers. Serious cruisers
As I advocate or negate each
category I switch hats. Talking from that camps point of view, but modifying my remarks
with our personal experience. In all cases we assume a well designed state of the art boat
oriented towards our purposes mentioned above.
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- In the size range were talking about, a catamaran has about the volume of a
10 longer monohull i.e. a 42 Catamaran has about the space of a 52
- A refinement. Especially if youre considering load-carrying capability, for a
monohull: subtract the ballast figure, plus about 15% of the total displacement (to allow
for heavier rig and structure to carry the keel loads) and then look at Cats in the same
displacement range as the result. Now youre comparing apples to apples!
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For now, were leaving them out of this discussion. Quite simply, there are
virtually no production boats that have the volume.
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Were not talking racing. Were talking boats that a couple can handle. Perhaps
with power assistance. Power winches. Furling sails. The works. Boats in the 40 to
55 range, perhaps. Our boat is in the moderate to heavy displacement side so that it
can carry the tankage, stores and equipment needed for longer cruises.
- Tacks easily. The combination of weight with a homogeneous, relatively
concentrated mass and with a keel to pivot onthis contributes to easy tacking.
- Goes upwind well. Ask to see polars. These revealing charts show the actual VMG of
different boats under a variety of conditions with various angles to the wind. A demo sail
by itself proves little. Anything compared to nothing is still nothing! You need to sail
along side the boat youre comparing. You need two competent skippers and a bench
mark boat. If you cant do that, get the polars!
- Large load carrying capacity. Adding a significant amount of weight to an already
relatively heavy boat with a sail plan large enough to power this weight is relatively
insignificant. (2000# added to a 40,000 # boat is only a 5% increase.) A side benefit?
Relatively lower tech construction methods that are less expensive can be used because
weight isnt as critical. These are proven methods, which appeal to our conservative
nature. Choosing your monohull is like choosing your car. If you re choosing a
vehicle to go cross country, towing a trailer with amenities, you choose a big, rugged, 4
WD, heavy vehicle. For in town, something small and light and easy to handle. No one boat
does it all, monohull or multihull. You have to decide on your priorities.
- Traditional good looks. Resale value. Appeals to the traditionalist, though some of
the latest crop of monohulls could leave you wondering. There are more people that
identify with monohulls and more of a mass market. Multihullers are making progress. This
has been the fastest growing segment of the sailboat market for the last couple of years.
If youve been to a major boat show latelyyou know.
- Motion comfort. The concentration of mass, and relatively smooth hull sections (with
a fairly deep, slack bilge sectionwere talking about cruising boats here!)
promote a comfortable motion at sea. By depending on ballast, not just form stability, you
achieve a degree of motion comfort that many people are used to.
- They heel. Its true. However, modern sail handling options such as in-mast
furling allow you to control the amount of heel by easily adjusting and balancing the sail
area all from the cockpit.
- The rig is larger. In order to maintain performance with this heavier displacement,
we need to have a bigger rig to supply power in lighter airs. This makes it more difficult
for a couple to handle. Again, with modern equipment, electric winches, in-mast furling,
etc. even the frailest of couples can handle a 50+ footer today. Truly, the age of push
button sailing has arrived. (At the end of this presentation, take our test to see what
kind of power aids you might need.) In the end, it all becomes a trade off of money for
ease of handling and conveniencehas it ever been otherwise?
- Volume vs length? Displacement is the measure of volume. Longer length gives you
more motion comfort, in general. You can have a short, heavy fat boat with the same volume
as a long, narrow lighter boat and both may have similar volume, though the prices may be
similar. I can assure you, though, that the longer, lighter boat will sail better and have
a more comfortable motion. The days of the old heavy designs built in Taiwan or elsewhere
are slowly drawing to a close with lots of kicking and screaming going on. However the
obvious superiority of the more moderate displacement boats coupled with lighter weight
amenities benefits both monohulls and catamarans! Remember, were talking about boats
designed for motion, sailing and live aboard comfort for a couplenot a cast of
- Safety. Now weve opened Pandoras box!. If a monohull has its hull
seriously compromised, (thats slick talk for
gets a big hole in it) it will
sink. While we could write a book on this, we dont need to. Several others already
have. People who have spent time in life rafts and people who have limped home with
Well designed Catamarans, generally, are unsinkable and,
depending on the extent of the damage, can often just keep on sailing to
get to port for repairs.
Lets just say that getting a hole in your boat can definitely
ruin your cruise no matter what kind of a boat youre sailing. All any of us can do
is be prepared. Theres more on this subject at the end of this
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There are two main
issues to consider with cats. Form Stability and lightness.
Monohulls depend on
ballast and form stability. Build a monohull with excessive beam and a hard
bilge section and you have a clumsy boat that has a very uncomfortable motionbut
lots of form stability. Ballast provides the ultimate stability and, of course, the
ability for a monohull to right itself from a knockdownor even a summersault! (My
son actually experienced this on an S2 36)
were totally dependent on form stability. If we go wider (overall), we get better stability up
to higher wind ranges but the trade off is that the boat is harder to maneuver and harder
to find a dock for. Also, if we go wider in the individual hulls, we get
more stability and load carrying ability, but at some sacrifice in
performance. If we decrease the overall beam or beam of the individual hulls, we improve the above, but have to start
nervously eyeing the sheets at even moderate wind ranges of 15-25 knots. The alternative,
for a narrower hull, is to reduce sail area giving up light air performance or keep the
area and place higher demands on the competence of the skipper (something manufacturers
are less and less willing to do in todays litigious society). It behooves you to
find out what your designer had in mind, and what youre up for in terms of keeping
The mass market builders tend to be somewhat conservative
and seem to choose good overall designs with the right compromises.
Does it matter? Yes,
in a cat. We have more surface area, more stability and more motion comfort (when the
weight is kept out of the ends). (See Good Cat, Bad Cat). This allows us to average about
20% better passage speeds overall. To be a stable platform and have good motion comfort.
However, all advantages are lost if we over indulge in weight. Were looking for
comfort and a degree of luxury here. So how do we achieve it?
aircraft and other industries that have a lot more money to spend have provided some of
the new technology at lower cost. You may have heard the terms:
- Scrimp construction
- Vacuum bagging.
- Cored construction
- High tech resins and clothes
These technologies are more expensive and require consistent skilled labor. I mention
this because small companies who come and go all the time, often tout high tech
construction, but dont do enough volume to maintain a consistent high tech labor
force. Also, too much emphasis on technology can be a marketing ploy for the have-nots.
In talking to some of the best designers and manufacturers we have come to realize that
moderate, high-tech may be a better answer. We don' want the same thing racers want.
They want an un-yielding hull that translates every force into more speed. We want our
boat to flex when it bounces off a piling! As in all of life, look for a conservative
middle ground and longevity in the business!
Other ways we maintain
load-carrying capability for people and gear
- Use a water maker. Smaller, lighter on board tanks and quicker turn over give a
healthier water supply.
- Sophisticated refrigeration system instead of lugging ice.
- Lightweight generators, alternators, A/C systems with air-handlers and more.
In the end, in both
monohulls and catamarans we want to increase the hull length per person to increase the
load carrying capacity. And then be smart about it. Certainly, today, the technology is
there. Trade offs. Thats the game we always play. Within the limits of what you can
handle and how much you can spend or count on power handling equipment, the longer the
hulls, the better!
- Minimum heeling. This is great. Your wife may actually love you again. Sailing fast
and upright. Flying by monohulls on a reach. Set your coffee on the table, put the
autopilot on auto tack and tack the boat by yourself. The coffees still there when
you get back to it!
- Speed. Checking our captains logbooks, we find that on a passage where winds
are of mixed directions, catamarans average about 20% greater passage making speeds
compared to comparable monohulls.
- Volume On deck. Lots of cockpit and deck space. The right boat for a party. Lay on
the nets. Sit on the swim platform. Lounge in the cockpit or inside (not
beloweverythings at the same level) with wrap around windows. Lots of space
and connection with the environment.
- Privacy. In addition to room to spread out on deck, the sleeping accommodations are
totally separate. Located in each hull, in opposite corners. True privacy. Separate head
access. Lots of storage. Ventilation planned for the tropics. Comfortable.
- Handling. The rigs smaller because of the lower displacement. Its easier
to get around. Put the auto-pilot on tack, and you can casually let off one sheet and take
in the other with no help, and the crew/guests continue reading or eating, or whatever
without even realizing that you tacked.
- Safety. Youre unsinkable. See the discussion.
- Tacking. With a cat youre like a light displacement monohull. You dont
have displacement to carry you through. You have to carve a turn. Easy, but a different
- Upwind. A cat cannot generally point as high as a monohull. Does this mean you
cant go to windward with a monohull? No. If youre racing, you may lose some
tactical advantage. (This may be what your friends talk about when they denigrate a cat.)
However, once you understand the concept of VMG you realize that you can take advantage of
a cats natural inclination for speed off the wind. With polars in hand (well show
you!) you simply crack off a few degrees and sail enough faster to make up the distance
and arrive with or ahead of your monohull counterparts.
- Load carrying. Critics claim you cant carry the loads. Theyre right. But
you can take advantage of modern technology to reduce the dead weight of the boat, and the
weight of equipment and still end up with all of the amenities, and the performance that a
cat offers. Well show you how!
- Resale. Times are a-changn. In the old days, demand wasnt there
and Cats were a hodge podge of goofy designs. Now, the pendulum has swung. Cat demand
outstrips supply. Weve sold many used cats recently for near or more than the
owners originally paid. Relatively, cats sell for a greater per cent of their
original purchase price than monohulls. Ask us and well show you actual statistics!
- Docking, where will you keep them? Yes, in some areas you cant find a
traditional slip. First of all, with a hard bottom dingy in davits you can take a mooring
or anchor and have your own water taxi. One you dont have to drag around in between
ports. Next, weve found that because your cat has such shallow draft, it often
qualifies for shoal space right up close to the parking lot at many marinasareas
often devoted to small power boats that dont earn the marina owners much money.
Theyre happy to make more on a cat and often charge you less than normal rates per
foot. When youre a transient, you can generally tie up at the end of "T"
docks with no problems. New Marinas have parallel docks you can tie to. Often these were
set up for big power boats, but work great for cats. Bottom line? In 4 years of sailing
cats weve never had a problem finding a place to put them. In transient, or for a
season. Neither have our customers. In fact, Ill guarantee it. If I
cant help you find a place for your cat in the proximity of where you want to sail,
Ill give you your deposit back!
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safer? This is a frequent question.
It's simply not true
that Cats don't make passages. There are just so many fewer cats that you don't hear about
them as often, though you do more and more. (Also, the Yachting Press tends to report on
the much bigger monohull market where most of their advertising comes from! In the last
couple of years, however, Catamarans have been the fastest growing part of the sailboat
market, growing over 20% faster in each of those years!) In fact, most of our cats start
their life with a transatlantic delivery trip from France! (Quite a shake down!) How many
Monohulls can make the same claim?
The bottom line is
that there is no one answer. Here's the facts (concerning well designed monos vs well
The most common problem in the ocean is floating debris (recent articles in Offshore
Magazine, Soundings and others have pointed to the frequency of containers falling off
container ships and remaining afloat) or, some say, basking whales.
If a monohull hits a
submerged object, and holes it's "everyone in the life raft"--if
you have time. The ballast keel makes it impractical to make a monohull unsinkable.
If a Catamaran gets
holed, it has several watertight compartments and not only won't it sink, but it can
probably continue on to a repair port safely! Of course if all compartments got holed, it
is unsinkable, and makes a h... of a lot better life raft, even with some water sloshing
around than a 6X6 raft or whatever!
True, Monohulls are
generally self-righting, and so long as all the ports are closed and the hatches (main,
cockpit & deck) fully dogged down and secure they can roll completely over, or get
tumbled in large waves and re-right themselves (generally sans rigging). If they don't
take in too much water, they can be pumped dry and await rescue. (Like with Cats, this
kind of tumbling is more likely from huge waves than wind.)
Occasionally you see a
picture of a catamaran upside down (and still floating). Invariably when you check, it's a
racing boat. The problem is that because a Cat is so light and buoyant, if you
don't slow it down in large waves (with drogues or whatever) the boat can surf down the
wave, plunge it's bow into the wave in front and flip. Racers don't slow down much. They
to maximize advantage. But let me ask you this. If you were coming off a 65-MPH highway
onto a sharp curving 25-MPH exit ramp would you insist on taking it at 65? If you did, you
would probably roll your car! The point is, if you got caught in huge 40' + seas, you
would take prudent steps to slow down. We've talked to captains who rode these kinds of
seas to sea anchors and were able to keep a cup of coffee level on the table! (Dont
try this trick at home, though!) Also, with the generally higher reaching speeds of a Cat,
and modern radio and communication equipment, you get word well in advance of approaching
storms and can sail (on a fast reach) at right angles to an approaching storm and
ultimately avoid the large waves associated with them. Storms typically advance at about
10-15 knots, while you can easily sail a cat on a reach at these same speeds rapidly
changing your bearing away from these storms.
And so what if you
screw up. You go too fast and flip your Cat? Well, at least it doesn't sink. All Offshore
Cats that meet offshore cruising requirements have appropriate reentry hatches which
allow the crew to re-enter the overturned hull to retrieve water, food and gear while they
sit on a large, upside down platform with their EPIRB turned on awaiting rescue. The
overturned Cat is a lot easier to find (and photograph, unfortunately) than a tiny life
The bottom line is
that there is no second chance in a monohull that gets holed and this is an
uncontrollable, more and more frequently encountered event. You do have control of your
speed in a multihull in large waves and so can prevent capsizing and, you do have a second
chance if you're either holed or capsized!<
Hope this puts the safety issue in perspective. See Good Cat Bad Cat for
more specifics on good catamaran design for offshore sailing.
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So, in the end,
theres no absolute right answer. Theres always trade offs. I sincerely feel
that once you share your expectations with me, I will be able to give you the information
and insights that you need to make a decisionwhether youre planning to buy, or
charter. One aside. A straw poll of our captains who deliver both monohulls and catamarans
transatlantic, comes out overwhelmingly in favor of catamarans. Ease of handling with a
short crew and comfort are generally sited as the reasons. You go figure... Call me
Eric Smith 410-263-2311
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