Introduction

For your reading pleasure, I have attempted to assemble some decision points and related data in the search for an offshore cruising boat capable of a circumnavigation.  Boat designs are a long series of tradeoffs in which a buyer must take positions and make a decision.  I am by no means an expert in marine design but wanted to summarize some of the information collected in our research in finding and purchasing a boat.

Mono vs Catamaran

For some reason this topic is controversial between owners of each type with debates as to which hull form is “better”.  No one hull form is better, but you must pick the design that best matches your cruising plans.  Form follows function as the famed architect Louis Sullivan was quoted.  Deciding on what type of cruising you are preparing to do is the most important consideration in this first fork in the boat purchase decision tree.  Every boat is a combination of compromises.  In simple terms you should consider a catamaran if you plan to spend most of your time in the following activities:

• Sailing with wind on the beam or aft of the beam (tradewinds sailing) and are open to motoring or power sailing upwind
• Have a larger crew count and/or family aboard
• Sail in lower latitudes
• Plan on spending most non-passage time at anchor and little in marinas
• Will have frequent guests onboard
• Will not carry large amounts of personal items or stores aboard
• Primary cruising grounds are shallow (Bahamas, Southeast US)
• Have adequate crew on watch to rapidly adjust sail plan to wind conditions
• Are open to higher annual operating costs (insurance, maintenance, fuel, berthing)

I would estimate that most offshore cruisers would answer yes to many of the items on this list and these sailors would match up well with a catamaran.

For the type of cruising we are planning, let’s look at some of the catamaran tradeoffs compared to a monohull:

1. Sailing at multiple latitudes.  Below 30 degrees North and South cruisers can depend on near constant easterly winds until you enter the low velocity ITCZ.  These trade easterlies are the winds used to complete downwind circumnavigations and we intend on using them.  However, our aspirations also include higher latitude cruising of the US eastern seaboard, New Zealand, South Africa, and Europe/Baltics.  One cannot control the wind/wave direction but can be prepared in a vessel that matches the conditions to best make your intended destination.  There is a reason why cruisers that primarily sail in the north Atlantic, roaring forties, southern Indian Ocean, and the SPCZ with big wind and waves in multiple directions tend to gravitate to monohulls.  On average a mono with moderate draft in moderate wave conditions has a tacking angle of 90 degrees (45 degrees off head to wind non-apparent).  An average production cruising cat with fixed keels has a tacking angle of 100 to 110 degrees (50-55 degrees off head to wind) and will lose additional leeway (drift sideways) in anything but flat seas.  In addition, cats often experience upwind slamming of the bridge deck as wave action to windward intensifies.  There are some catamaran makes (Catana, Outreamer) better designed for upwind sailing that utilize dagger boards and higher bridge deck clearance that can compensate for the windward issues.  We have zero plans to set off on long legs to windward but experience shows the forecast models are never 100% accurate. We see the ability to sail higher as a safety issue that will allow more options in escaping fast developing weather systems or the ability to divert to closer ports more quickly without an engine if required.
2. Crew size.  The majority of our sailing will just be the two of us with occasional guests, so three or more staterooms is not required.
3. Marinas.  Catamarans have a tremendous advantage at anchor because they experience minimal roll.  However, outside of the US, berthing options are scarcer for wide beams and in some cases the charges can be 2x that of a mono’s LOA.  Because we are liveaboards, we plan on spending on average 120 days a year in marinas to enjoy some city conveniences, have better security, ease maintenance projects, and facilitate errands/provisioning.  Having more dock options at lower cost at these international ports of call is a great benefit.  We will also have more options on yards for haul outs.  The cat does have a big advantage in maneuvering in the tight confines of the marina. In retrospect, rolling at anchor is the biggest reason we considered a catamaran.
4. Draft. Having shallow draft opens a great deal of cruising grounds.  There will likely be places we would like to go but cannot with standard draft.  Some people like to climb the mast and navigate around coral heads to get to the perfect secluded anchorage.  We prefer to stick to well-known channels.  Having to moor in the more populated traditional anchorages is a tradeoff we are willing to accept. Monohulls do have more options getting free from a grounding than catamarans.
5. Reefing.  Monohulls can heel and are therefore much more forgiving in surprise gusts.  In addition, mono helm feedback will give you an instant indication that a sail reduction is in order.  Catamarans sail by the numbers and the crew must keep a keen watch of the wind and speed instruments to not risk damage to the sails or rig.  This degree of monitoring by a couple is not desired over long passages.  Jim has been in two surprise microbursts in apparently normal storms and was caught off guard in the very high wind velocity in each.  Jim has read most of the accident reports regarding capsized catamarans and a common theme is the inability to slack the sails in time for big microbursts.  After writing this point, we watched a video of an experienced cat cruising couple lose their wind instruments (always the first to go) and near panic followed during a gust trying to determine the wind velocity as well as the wind direction to shorten sail.  On a mono one just has to run off until the puff dies or the decision to reef is made.  In the worse case you may suffer a knockdown on a monohull, but your sails and rig should stay unharmed.
6. Weight.  Since we will be full time liveaboards with extended stays away from population centers, we plan on loading the boat with provisions and equipment.  Monohulls are much less weight sensitive to loads and speed is not as much decreased.  We have read that cat cruisers often forgo equipment such as generators and washer/dryers to keep the weight down.  Without a generator cats must run an engine to charge the batteries and make water.  To accommodate loads, livaboard cat cruisers will compensate by purchasing a vessel larger than their space requirements to allow for more weight aboard thus increasing their operating costs.  Others choose to just load their cats down and accept the slower passage speeds.
7. Operating costs.  The ability to retire early to most is contingent on controlling operating costs.  Insurance for similar cost monos is less than cats.  Maintenance is less as well since there is one less engine and less overall surface area to upkeep.  The demand for catamarans is higher so they carry a price premium.  Mono fuel costs may be less because of one less engine and the ability to sail upwind more than under power.  Additionally, there are the lower berthing fees mentioned previously.

In summary, we believe our cruising requirements are divergent to most of the buyers in today’s blue water market and match up best with a monohull, however, the decision was close.