If you’re contemplating buying a multihull for bluewater sailing, be it a new one or a brokerage yacht, what equipment and spec should you be thinking about? The choices you make could determine much of your experience along the way, from comfort at sea to safety, but you don’t want costs to mount up unnecessarily. Where’s the right place to draw the line?

For this feature, we consulted two very experienced bluewater sailors with oceans of multihull miles behind them, catamaran owner Chet Chauhan and coach Nikki Henderson, for advice and guidance.
Here, they look at what they consider the most important priorities, from downwind sail choices to energy requirements – and not neglecting essentials such as a robust workhorse tender.

It is aimed squarely at speccing a multihull, but many of their recommendations would be applicable to bluewater yachts of any type.

Sail choices and rigging options

Nearly all bluewater catamarans will come with slab reefing, which is simple and durable. Make this system work as efficiently as possible. Check what your mainsail car system is, and possibly upgrade the cars to ones with roller bearings to reduce friction. The smoother the mainsail can drop, the better.

Fit downhaul lines for each reef on the luff to make downwind reefing easier. Ideally, run these back to the same winch station as the reefing lines and halyard. On that note, the ability to reef from one place is important. Running back and forth from port to starboard to control reefing lines and halyards is not practical and increases the risk of a slip or a fall. Check that the winch layout allows that.

When it comes to headsails, buy more than one for redundancy. If your budget is limited, make your extra sail the storm headsail. If you can afford it, choose a blade headsail as well for your ‘everyday’ headsail, and a higher clewed, larger reaching headsail for long downwind legs.

Headsails made from laminate sail cloth and fitted with extra UV protection when furled are a worthy investment. They weigh less, which makes changing sails short-handed much easier.

If you opt for a spinnaker or other loose-luffed sail, getting it down easily is critical. The sock system you choose to douse it needs to be robust. I find that fibreglass rings work best.

Lengthen the sock-line so that it can run down through a block on the foredeck and back to a winch sited aft, close to where the sheets are controlled; this will make dousing the sail easier. Wobbling around on the bow getting your legs caught up in the sock line isn’t fun.

When it comes to asymmetrical sails, it’s all about furlers. Stick with the traditional furlers for a Code 0 or a flatter gennaker, and consider a top-down furler for a true asymmetric.

Unless you’re a performance-orientated sailor buying a performance catamaran, the ability to sail dead downwind is important. Ideally, invest in a symmetric spinnaker.

If you have a performance catamaran, first buy a heavy spinnaker to withstand any squalls. For cruisier catamarans, choose a lighter and larger S2 because it will help in lighter airs and you won’t have the acceleration to safely sail through a squall with it up anyway. If you are limited in budget, not a confident spinnaker sailor, or want a more robust heavy weather option for dead downwind sailing, poled out twin headsails (jib/genoa) is a great alternative. Just make sure you have two tracks in your headsail foil.

For controlling all the sails, lines that run aft to inboard winches are much easier than lines that run to winches by or at the mast only. At the very least, you should be able to hoist and drop the mainsail and adjust reefing lines and headsail sheets from a position where you can also see a chartplotter and adjust the helm manually.

Ready for heavy weather

I recommend having your mainsail built with three reefs. But before requesting this, check the boom has the space for three sheaves, or even four if you have an adjustable outhaul at the aft end – sailmakers and riggers don’t always communicate with custom changes.

If you have a furling headsail and no inner forestay, ensure your storm headsail can be hoisted over the top of it. To my mind, an inner forestay is the better option for a storm headsail, as you can rig it ahead of time to be ready if the weather worsens. It’s also arguably less physical a task to hank on a headsail than it is to slide one over the top of the jib or genoa right at the bow.

If you are cruising anywhere you could meet major rough weather, I’d buy a series drogue. This will help you slow the boat down. Tying warps together is also an option, but lean on the rope option as a plan B. Don’t rely on mooring lines for this as they’ll be unlikely to fit on your winches. Whichever you use, practise it so that you don’t have to invent it in anger.

Cockpit security

If you sail with children, an enclosed cockpit (or a way of enclosing it) is important to create the boundaries they need to have an essence of freedom. The same goes for pets.

An enclosed cockpit not only protects the crew from falling out, but also prevents water from coming in. Tradewind sailing comes with big swells, and the acceleration and deceleration – which is especially pronounced when sailing deep downwind with a symmetric spinnaker – can occasionally result in big quantities of water flooding the aft decks. An enclosed cockpit is the ideal, but you could also consider fitting removable barriers if you prefer the option to be able to walk straight from the saloon into the water on anchor.

Safety gear and features

Many catamarans have a helm station that is only accessible from climbing up a ladder or stairs which are very far aft, without any real protection from falling backwards straight into the sea. I recommend choosing a boat that has a more protected helm access. This will also improve visibility. A helm that is low down and far aft could obstruct the view and communication to the bow on the opposite hull.

For man overboard scenarios, a drop-down ladder on the side deck that can be deployed quickly is important. While the stern seems the obvious recovery location, it is not the ideal first point of contact with a crewmember in the water due to the proximity to the propellers.

A hanging ladder provides the casualty with something to hold onto initially. On the topic of ladders, ensure the ladder on the stern is deployable from the water in case you forget to put it down before jumping in for a refreshing dip while at anchor!

Think carefully about jackstay placement. Jackstays that run along the stanchions on the outboard-most part of the vessel can actually be a hazard; if you fall overboard while clipped on, you will drag in the water. Look for ways, or ask the manufacturer, to run jackstays further inboard. You need to be able to get to the helm, to the mast, and to the bow while always being clipped on. I would advise investigating this early in the build, as extra strong points may need to be fitted.

A crew overboard emergency GPS button, a VHF transmitter, and a chartplotter or iPad/iPhone holder at the helm are, for me, deal-breakers.

They are arguably more important on catamarans than monohulls as the distance between the helm and the navigation station can be substantial and involve several flights of stairs.

Water

I sailed halfway around the world without a watermaker and have just completed another half with a watermaker, and I can say the difference in comfort is profound. We no longer have the constant anxiety of finding good water sources and we have the luxury of taking a shower everyday.

A DC rather than AC watermaker is the way to go so you are not reliant on a generator. But even if you do have a watermaker, you also need a way to purify the water. Yes, watermakers do produce the purest water, but after sitting in your tanks without chlorine for a few days in the tropical heat, bacteria and viruses can grow. You could add chlorine every time you make water but it is hard to keep track of the concentration.

A good solution is to add a separate tap in the galley for drinking water that goes through a carbon filter and ideally UV light as well to kill any remaining pathogens. Some units also have filters that add back calcium and other minerals that watermakers remove.

Anchoring

A bulletproof anchoring setup is a critical consideration since the majority of the time you will be on the hook. Modern anchors (Rocna, Spade, Manson, Ultra etc) are very reliable across the majority of the seabeds you will encounter.

Bigger is always better but, with catamarans being weight sensitive, a good compromise is to get an anchor only one size above what the manufacturer recommends. Couple that with around 70-80m of high test chain that has better strength to weight ratio and a sturdy bridle and you are all set – literally!

Lastly, the chain hook that connects the bridle to the chain is something that should not be overlooked. If you are anchored in shallow water and the bridle is slack and resting on the seabed, the chain hook could easily come off. To prevent this, it is good to have a hook that is secured with a pin or bolt.

Tender dinghy

Cruising sailors always say their dinghy is their car, and like your car it’s often the limiting factor on how much stuff and people you can transport. So get the biggest dinghy that can fit on board or on davits, but not so heavy that it affects the trim and therefore the performance of your boat.

You will also need a good tender anchor that can hold the dinghy in 20-knot wind and waves for when you are snorkelling or diving, but also in an emergency if the outboard engine cuts out and you can’t row against the wind or current.

In a lot of remote places you will have to beach the dinghy to land, so having a good pair of dinghy wheels can make it a lot easier and will spare your back.

Lastly, many dinghies are sadly stolen so it’s wise to secure it with a sturdy chain and the biggest padlock you can find.

Handover and after-care

Anyone planning to sail thousands of miles from land really needs to understand their boat back to front, and with a new boat the role of the manufacturer is critical. A quick six-hour run through where you are given the keys and shown how to turn the engine on is not a sufficient handover.

Before you buy, find out as much as you can about the length of time and training you are going to receive on handover and the expertise of the people who will be giving that handover. They should be sailors or engineers and not sales staff.

Ask also about the quality of the manual, as-built drawings, plumbing and wiring diagrams that come with the boat. You are going to need these. Will they be enough to troubleshoot problems?

Find out more, too, about the length and commitment of the warranty (and ask other owners for their experiences). If there are major issues with the build, will they be covered? How will it be dealt with?

A strong community of owners of the same brand of boat as yours will be invaluable. There are many very active owners’ associations and groups, and they are worth their weight in gold, so if they have some sort of forum to communicate on, this is a huge plus. It will be a resource for helping troubleshoot problems, find crew and also to make friends.

Bluewater sailing can be an isolating venture, and a sense of camaraderie and practical support among owners of the same type of boat as yours will mean more and buy you more than you might expect.

The balance of power

When preparing a boat for bluewater cruising, one of the most critical considerations has to be energy. How are you going to power the instruments, autopilot, lights, fridges, laptops and all the appliances you can’t live without?

It’s important to first start with a calculation of how much energy you plan to use at anchor and underway. This means having a list of all the energy consuming equipment, coupled with the amount of energy they consume in a 24-hour period. You should come up with a table something like this, which is based on typical energy consumption at sea for us as a couple on our Nautitech 46.

This will show you how much energy you need, and help you size the boat’s energy sources as well as that of the house battery.

You’ll tend to use a lot more power underway because of the autopilot and instruments, but it’s also worth remembering that you’ll be spending a lot of your time at anchor. Ideally you want to optimise your energy sources so that renewables cover your energy usage at anchor on most days.

There are many ways to power a boat, each with their pros and cons.

Catamarans do have the advantage of having a lot of space to fit solar panels. This is why it’s better to go all-in on solar first before adding other sources of energy. A transom solar arch works very well because it’s not shaded by the hoisted mainsail, and the solar panels can dissipate heat more effectively than if fitted on the coachroof, which increases their output.

Once you max out on panels on the arch, add them to the roof but these will produce less. On the curved surfaces of the roof, flexible panels fit better but are about 20% less efficient than rigid panels so factor this into your energy projections.

With a solar arch and additional panels on the roof, you’re likely to have enough power to meet all your energy needs at anchor on most days, although obviously this depends on where you are cruising. In a Mediterranean summer with up to 16 hours of sunlight and cloudless skies, you’ll have little problem topping up the batteries. In the tropics you are looking at 12-hour days with 20% cloud cover on average.

A rough rule of thumb is to divide your total solar capacity by five (low end) or three (high end) to get your output in amp hours. For example, 1,200W should give around 240-400Ah per day. Finally, to maximise output it’s important to have separate MPPT controllers for every large panel or every 400W.

On passage, with the autopilot working hard and the mainsail shading the solar panels, you may need additional sources of power. Topping up with the alternators is a cheap way to cover this if it’s only for a few hours a day. Installing high output alternators can halve this time, and some people install hydro generators and wind generators, which also have their pros and cons.

From our observations in anchorages around the world, more and more boats are getting rid of gensets. This is partly due to better solar and lithium battery technology but also because of new 12V air conditioning systems. And when sailing in remote places, diesel can be hard to come by. For example, I’m writing this anchored in Nuku Hiva, the largest island of the Marquesas in French Polynesia, and they’ve run out of diesel. Even when the ship arrives in a week’s time, it will be rationed to 100-200lt per boat.

Finally, you need to store all this power you’re generating so batteries are the next piece of the puzzle. Lithium is becoming the standard on all new boats and especially on weight sensitive catamarans. When sizing your battery bank, a rough rule of thumb is to have capacity for at least 1.5 times your daily power usage so you can store enough power to tide you over for at least one bad day of solar production (a day and two nights).

To power all the AC appliances you’ll need an adequately sized inverter of at least 2,000W and, lastly, it’s critical to have a battery monitor to see the state of charge of the batteries at all times.

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