Blue Water Sailboats: Your Guide to Offshore Cruising

In a Nutshell...

A blue water sailboat is a tough, self-sufficient vessel designed for long-distance ocean passages. They are built to withstand severe conditions, operate independently for weeks or months at a time, and provide a secure, comfortable home for their crew. Selecting the right one means balancing size, displacement, sailplan, and vital systems to ensure safety and comfort on the high seas. Ultimately, the best choice is a boat that feels right, is manageable by its crew, and inspires confidence for the journey ahead.

A Brewer 44 cutter-rigged sailboat at anchor

A typical bluewater sailboat—the Brewer 44 cutter

What Exactly Are Blue Water Sailboats?
What to Look for in a Blue Water Sailboat
The Anatomy of a Blue Water Sailboat
Onboard Systems & Maintenance
The Crucial Role of the Tender
Offshore Navigation & Weather Routing
Summing Up
Frequently Asked Questions

What Exactly Are Blue Water Sailboats?

Blue water sailboats are the undisputed workhorses of the cruising world. They're built for big oceans and long passages, often crewed by live-aboard sailors who have cut loose from life ashore, choosing a path of seaborne adventure and exploration.

The European Commission's Recreational Craft Directive (RCD) defines a Category A vessel as being "designed for extended voyages where conditions may exceed winds of Force 8 on the Beaufort Scale (over 40 knots) and significant wave heights of 4m (13 feet) and above, and vessels largely self-sufficient." The key phrase here is 'largely self-sufficient'. A blue water sailboat has to be a home, a transport system, and a lifeline all in one. As a yachtmaster who has sailed many offshore miles, I know that when you're 1,000 miles from the nearest land, your boat is your only refuge. These are the boats that stand up to the challenge.

What to Look for in a Blue Water Sailboat

Choosing a sailboat for blue water cruising is a deeply personal decision, but it's one that should be guided by practicality and experience. Let's talk about some of the key features a couple might want to consider when they're looking for their offshore monohull.

Size Matters: Big Enough, But Not Too Big

The temptation is always to go larger, but resist it. While a good large boat will always be more seaworthy than a good small one, you must be able to handle it easily. A boat that's too big can turn a minor problem into a full-blown crisis.

You'll need a lot of stowage space for spares, equipment, food, and water for passages that could last a month or more, so anything less than 38 feet is unlikely to provide what you need. A sailboat in the 42 to 45-foot range is a great size for a cruising couple, offering enough space for stores and the possibility of a comfortable layout with room for occasional guests or extra crew.

Some sailors with deeper pockets choose much larger yachts specifically designed for short-handed crews, like the famous Apogee 50 by Chuck Paine or Steve Dashew’s Sundeer 64. Their light, easily-driven hulls mean a relatively small, easily handled rig is all that's needed to push them along at a decent speed. But remember, a boat that's a handful to manage will sap the fun out of your adventure.

Heavy or Light Displacement?

This is one of the most debated topics among blue water sailors, and there is no simple answer.

A heavy displacement hull with a full keel and long overhangs will give you a wonderfully comfortable ride in heavy seas. The downside is that it will be slow in lighter winds unless it carries a lot of sail, which then creates a new problem of sail handling for a small crew.

A very light displacement hull, on the other hand, is fast but can be limited in terms of what you can carry without affecting its performance. It's also likely to be a handful in a proper blow.

My preference, forged over years of sailing, is for a moderate displacement hull. This gives you the best of both worlds—a good compromise between speed and comfort, with a fin keel and skeg-hung rudder for a solid balance of performance and protection.

A Strong, Robust Hull

The material of the hull is less important than its robustness and build quality. Fibreglass (GRP), steel, aluminium, wood epoxy, and ferrocement can all be excellent hull materials.

A modern, well-built fibreglass hull will last for a very long time, but a good steel or aluminium boat offers incredible strength and can shrug off bumps that would be catastrophic for a composite hull. Wood epoxy is beautiful and strong, while ferrocement boats are famously tough but often have poor resale value.

Hull Material	Advantages	Disadvantages
Fibreglass (GRP)	Low maintenance, relatively inexpensive, good resale value.	Vulnerable to osmosis, can be brittle on hard impact.
Steel	Extremely strong, easy to repair and modify, good value.	Prone to rust, requires a lot of maintenance, heavy.
Aluminium	Very strong and lightweight, low maintenance, corrosion-resistant.	Expensive to build and repair, requires specific welding skills.
Wood Epoxy	Lightweight, strong, stiff, and beautiful.	Higher initial cost, complex build process.
Ferrocement	Very tough and inexpensive to build, low maintenance.	Heavy, poor resale value, can be difficult to survey.

An Easily Handled Sailplan

Manageability is the key to an enjoyable passage. The ideal sailplan allows you to make adjustments and reef sails without a lot of drama or relying heavily on electric winches and other powered devices.

For me, a masthead cutter is the perfect choice for an offshore boat. You get a versatile rig that can be balanced in a variety of wind conditions. I'd opt for a twin-groove furler on the headsail, a hanked-on staysail for heavier weather, and slab-reefing on the mainsail. I’m not a fan of in-mast or in-boom furling systems on blue water boats, as they're one more thing that can fail at the worst possible moment. In a storm, you can quickly swap the staysail for a hanked-on storm jib and set a separate tri-sail on its own track.

For long periods of downwind sailing in the trades, a twin-head rig is a game-changer, with two poles, each with its own uphaul, downhaul, and foreguy. A cruising chute or conventional spinnaker will round out the sail wardrobe for lighter air.

Granny Bars

If you have halyards and uphauls at the mast, I strongly recommend installing 'granny bars'—those stout rails on either side of the mast. They provide a reassuring handhold in lively conditions and are great for tying off lines to stop them from banging against the mast at night. They're on my 'to do' list for Alacazam.

The Anatomy of a Blue Water Sailboat

Beyond the basic design, a host of other features and systems define a true offshore cruising boat.

Fuel & Water Capacity

Sooner or later, you'll find yourself becalmed. It's an unpleasant inevitability, and it's then you'll begrudgingly reach for the engine keys. Having enough fuel to motor at four to five knots for 500 nautical miles or more is a reassuring safety net. For a typical modern 35hp engine using about a half-gallon of fuel per hour, a 60-gallon capacity is about right.

For water, a minimum of one imperial gallon per person per day is a good starting point, with a 20% contingency. So for a two-person transatlantic trip of say, three weeks, you'd want at least 50 gallons. Ideally, a boat would have double this, split into two separate tanks so that if one gets contaminated, you still have a backup supply. A manual water pump at the galley is a must for conserving both water and battery power. A separate seawater supply at the sink is also a great feature. While a reverse osmosis watermaker is an extremely useful device, you should never rely on it as your sole source of drinking water. They can and do break down.

The Cockpit

An aft cockpit is generally preferred on a blue water boat. It should be deep, secure, and well-drained, offering excellent shelter for the crew. The sheets for the headsail, staysail, and mainsail should all be within easy reach of the helmsman for fast adjustments.

Ventilation Below Decks

Adequate ventilation is absolutely critical, especially in the tropics. A good number of opening deck hatches and portlights will help get a cooling breeze through the boat when you're at anchor. Make sure they have insect screens! At sea, in bad weather, dorade vents are a clever solution that allows fresh air in while keeping water and spray out.

The ingenious dorade vent provides ventilation below deck while keeping water out

How a dorade vent works

Self-Steering

You'll soon get tired of helming. While a good electronic autopilot is essential for motoring and short passages, a windvane self-steering system is the way to go under sail. They are a mechanical marvel, operating without any electricity, and can steer the boat reliably for weeks at a time. It’s the single best piece of equipment on Alacazam.

Sea Berths & Handholds

Secure sea berths are a must for off-watch crew. They should be parallel to the boat's centreline and fitted with lee-cloths to prevent you from being thrown out of the bunk. Below decks, it must be possible to move from one secure handhold to the next without a break, from bow to stern. This is a fundamental safety requirement and a good indicator of a boat's offshore design credentials.

Protection from the Weather

A solid sprayhood, or 'dodger' as they're known in the US, is a game-changer. It shelters the cockpit and its occupants from wind, rain, and spray. It can be a rigid structure or a canvas version built on a collapsible frame. UK sailors know 'dodgers' as the weather cloths fixed to the guardwires to provide additional shelter. Don't forget a bimini, either. Too much direct sun can be far more damaging than a bit of rain.

Anchors & Ground Tackle

A reliable anchoring setup is non-negotiable. At a minimum, you should have at least two adequately sized anchors. The primary 'bower' anchor should be ready in the bow roller with an all-chain rode of at least 60 metres (200 feet). The secondary anchor can be a combined rope and chain rode and stored below decks.

The Galley

The galley stove must be gimballed and fitted with sturdy fiddles and pot clamps to keep everything secure when the boat is pitching and rolling. Padeyes for the cook to clip their harness to are also essential. An offshore galley is designed for safety and efficiency first, and comfort second.

Essential Systems & Electronics

Modern offshore cruising would be much harder without a reliable electrical system. Solar panels, a wind generator, or a hydrogenerator are all vital for keeping the batteries topped up. A robust battery bank with a decent inverter is also key to running everything from a watermaker to a laptop. For navigation and communication, a good chartplotter is essential, but you should also have paper charts and a sextant as a backup. A satellite communications device like an Iridium Go or Starlink is a must for weather routing and staying in touch with the world.

Onboard Systems & Maintenance

When you’re hundreds of miles from the nearest chandlery, you are your own mechanic, plumber, and electrician. A blue water boat's self-sufficiency isn't just about carrying enough food and water; it's about having the tools and spare parts to fix things when they inevitably break. From my years of sailing, I've learnt that the key is a comprehensive spares inventory and a robust tool kit.

Your spares inventory should include parts for your engine, rigging, plumbing, and electrical systems. Think about the consumables you use most often, such as fuel and oil filters, impellers, and drive belts. For the rig, a selection of shackles, wire splices, and replacement lines can save a passage. When it comes to the boat’s core systems, carrying spare pumps for freshwater and bilge systems, along with repair kits for your heads (toilet), is simply prudent.

Your tool kit should be organised and extensive. You'll need more than a basic set of spanners and screwdrivers. A good set of marine-grade electrical tools, including a multimeter, crimping tools, and soldering equipment, is essential. For mechanical issues, having a socket set, vice grips, and a hacksaw can get you out of a real bind. Remember to keep everything clean and dry to prevent rust. Ultimately, a blue water sailor is an on-the-go tradesperson, and you should be equipped accordingly.

The Crucial Role of the Tender

A tender, or dinghy, is much more than a way to get ashore; it is a vital part of the blue water cruising lifestyle. It's your taxi, a second exploration vessel, and a critical component for boat maintenance and security. A good tender makes life at anchor immeasurably better.

There are a few types to consider. An inflatable tender is lightweight and easy to stow, but its soft bottom can make it slow and wobbly. A rigid inflatable boat (RIB) is much more stable and seaworthy, but it takes up a lot of space. Then there are rigid tenders, which are incredibly durable and can be rowed or sailed, but they're often heavy and awkward to handle. Most sailors opt for an inflatable with a sturdy outboard engine for a good balance of speed and convenience.

Storing the tender is another key consideration. While at anchor, it will likely be tied off the stern. But for a passage, you must secure it properly. Davits on the stern make it easy to lift and lower, but they add weight. Alternatively, stowing the tender on the foredeck or deflating it and storing it in a locker are common solutions.

Offshore Navigation & Weather Routing

While modern electronics have made navigation incredibly straightforward, a blue water sailor knows that technology can and will fail. You must have navigation redundancy built into your systems and your skillset.

Redundancy means having multiple, independent ways to know where you are. Your primary tool may be a modern chartplotter, but you should always have a set of paper charts for your planned route. They don't run on electricity and are a fantastic backup. Beyond that, a handheld GPS is a great safety net, and knowing the basics of celestial navigation can provide peace of mind.

Weather routing is also critical for planning a passage. You can access up-to-date weather information using a satellite communications device like a Starlink system or an Iridium Go. However, the technology is only half the battle. You must learn to interpret the data, understanding pressure systems, wind shifts, and the signs of developing bad weather. A skipper who can read the clouds and feel the changes in the air will always be a better sailor than one who relies solely on a screen.

It can be a big job to outfit a boat properly, but understanding the core features and how they work together is the first step towards a successful life at sea. For a broader overview of the subject, you can also refer to our guide on The Essential Features of All Good Cruising Sailboats.

Summing Up

While this is by no means an exhaustive list of all the desirable features in a blue water sailboat, it's a solid foundation for your search. The best boats are not simply the newest or most expensive; they're the ones that have been carefully designed and maintained with a deep understanding of what it takes to operate on the open ocean. Ultimately, a blue water boat should be a home you trust to get you safely to the next horizon and beyond.

This article was written by Dick McClary, RYA Yachtmaster and author of 'Offshore Sailing' published by the Royal Yachting Association ( RYA) and member of The Yachting Journalists Association (YJA).

Frequently Asked Questions

What is the ideal length for a blue water sailboat?

While personal preference varies, a boat in the 42 to 45-foot range offers a good balance of space, comfort, and manageability for a cruising couple.

Is a catamaran a good blue water sailboat?

Yes, many modern catamarans are excellent for blue water sailing. They offer greater living space, speed, and comfort, but can be more expensive, have less payload capacity, and can be more difficult to maintain in remote areas.

How much freshwater should I carry?

A general rule of thumb is to have a minimum capacity of one imperial gallon per person per day for your longest planned passage, plus a contingency allowance.

How do I handle sails in heavy weather on a blue water boat?

The key is to have a versatile sailplan with easily reefed sails. A hanked-on staysail and a dedicated storm trysail track are excellent features for safe handling in strong winds.

What are the most important safety items to have?

Beyond the mandatory equipment, a reliable EPIRB, a good quality liferaft, AIS (Automatic Identification System), and a robust set of harnesses and tethers are all essential for offshore safety.