Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Yacht keels

The keel kind is without doubt one of the most essential options of your boat. However the completely different designs might be complicated, so I’ve got down to create a really clear information that can assist you perceive sailboat keels as soon as and for all.

What are the most typical sailboat keel sorts? The commonest sailboat keel sorts are full-length keels, fin keels, bulb keels, wing keels, bilge keels, and lifting keels. Full keels are well-liked amongst cruisers, whereas fin keels are usually used for racing. Bilge keels and lifting keels are sometimes utilized in tidal waters, on small fishing boats for instance.

On this article, we’ll discover the most typical keel sorts collectively. I will use diagrams to essentially hit dwelling the variations of all these keel sorts, and we’ll talk about what keel sorts are greatest for liveaboard, ocean cruising, and lake weekend journeys. After studying this text, you will know what to decide on – and why.

Overview of Sailboat Keel Sorts

For those who simply need a fast overview, this is a listing with the most typical keel sorts and a brief description. Extra element will observe under.

The commonest keel sorts

  • Full keels run from entrance to aft and are essentially the most secure keel kind, making them the preferred cruising keel.
  • Fin keels supply the most effective efficiency however are much less comfy. This makes them well-liked for racing. Fin keels are bolted on to the hull and customarily run deep and skinny.
  • Bulb and wing keels are each variants on the fin keel.
  • Bulb keels carry further ballast within the tip, making them extra secure.
  • Wing keels have two suggestions on the finish of the keel, which reduces crossflow, bettering directional stability.
  • Bilge keels are double fin or double full kees, which permits the boat to be beached, making them the preferred keel for tidal waters.
  • Lifting keels are moveable keels that may be lowered and raised, permitting the boat to enter shallow waters as nicely.
  • Centerboard keels are a pivoting lifting keel, permitting to sail each coastal and inland waters.
  • Leeboards are fins on the perimeters of flat-bottomed hulls boats, making a keel pointless.

Properties of every keel kind

Keel kind Consolation Maneuverability Velocity Full keel +++ – – Modified full keel +++ – – Fin keel – ++ ++ Bilge keel + + – Lifting keel – ++ ++ Leeboards – – +++

sailboat keel types properties diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What does a keel do?

What does the keel do? A keel is a vertical blade working down from the hull. It’s weighted and acts as a ballast, countering the boat’s tendency to heel and stopping it from tipping over. The wetted floor beneath the waterline reduces slippage to leeward by making a monitor, which counters the sideway power of the wind on the sails.

leeway - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

The rationale sailboats do not tip over is that the burden of the keel counters the buoyancy of the hull, which suggests it’ll pull the boat downward. This downward power reduces heel and prevents the boat from rolling.

A canoe does not have a keel. Attempt getting into that: it’ll wish to roll.

It counters the horizontal power the wind places on the sails. Every time the power on the sails will increase, the resistance of the water on the keel will increase proportionally.

The heavier the keel, the much less heel you will get.

A keel reduces slippage to leeward. Slippage is just the quantity you fall astray due to the path of the wind and present. Leeward is the aspect of the boat behind the wind.

So if you do not have a keel, you’ll fall astray rather a lot as a result of the wind will push you over the water floor.

Additionally, you will heel rather a lot since there’s nothing beneath the water floor to counter the power of the wind excessive up in your sails.

A keel fixes each of those points and makes sailboats probably the most dependable boats in heavy winds and storms.

You possibly can learn on about how keels work right here.

Keel Sorts: Fundamentals

Keels might be labeled by a number of dimensions. You possibly can take a look at them from the aspect or the entrance. You may as well classify them primarily based on properties.

Earlier than I dive into every keel kind in-depth and present examples, let’s be sure we now have the identical place to begin.

There are primarily two types of keels:

  1. Fastened keels
  2. Movable keels
sailboat keel types classifications - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Fastened keels

Fastened keels are keels which are built-in into the hull or bolted on. They can not be moved or lifted.

When mounted keels, you’ll be able to divide them up additional primarily based on the aspect view. There are three primary classes:

  1. Full keels
  2. Fin keels
  3. Bilge keels
Full keels

Full keels are extra comfy, present higher stability and safety, however are additionally slower than fin keels.

Fin keels

Fin keels are much less comfy, present much less stability, are extra weak, however they’re additionally lots quicker than full keels.

Bilge keels

Bilge keels are double keels: one on all sides of the hull. This permits them to be beached, which is useful in tidal waters. They’re usually lots slower and fewer maneuverable in comparison with fin keels.

Movable keels

Movable keels might be lifted from the water, making a shoal (shallow) draft, permitting the boat to enter each shallow waters and coastal waters. This makes it a really versatile keel kind. There are two primary designs:

  1. Lifting keels
  2. Leeboards
Lifting keels

Lifting keels might be lowered and raised by means of a slit within the hull. Examples of lifting keels are the daggerboard and centerboard.


Leeboards are picket swords connected to the aspect of the hull and stop slippage to leeward, however they do not stabilize the boat, nor counter heel by including ballast.

leeboards dutch barge - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Tip design

With fin keels, there are completely different tip designs out there. The commonest two tip designs are:

  1. Bulb keels
  2. Wing keels

These are each variants of the fin keel. Typically, these keel designs are talked about in a single breath with full keels and fin keels, creating confusion on what sort of keel they’re. Nevertheless it’s essential to know that they’re a sub-category of fin keels.

bulb keel - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Rudder design

As with the tip of the fin, there are completely different rudder designs that will apply to each fin and full keels. The 2 commonest rudder designs are:

  1. Skeg rudder
  2. Spade rudder
Skeg rudder

A skeg is a structural a part of the keel in entrance of the rudder that protects the rudder. The keel encompasses the rudder, stopping any rogue ropes, weeds, or rocks from damaging the rudder.

fin keel with skeg rudder - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming
Spade rudder

A spade rudder is an unprotected rudder: it does not have any structural safety from the keel design. It’s merely connected to the hull. This design is quite common.

Alright, we perceive the massive image. Let’s dive into extra element for every keel kind and talk about the professionals and cons.

Full Keel

  • Fastened keel
  • Good for cruising and liveaboards
  • Snug
full keel sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a full keel? A full keel runs from entrance to aft for not less than 50% of the hull and is absolutely built-in into the hull. It has the most important wetted floor of any keel kind, and it’s also the heaviest. This ends in directional stability and lowered heeling, offering essentially the most comfy trip, but additionally the slowest.

The wetted floor merely means the quantity of water contact space. With such a big wetted floor, it decreases slippage to leeward essentially the most of all keel sorts, whereas it counters heeling essentially the most as nicely.

The total keel is essentially the most comfy and secure keel kind out there. Nevertheless, consolation comes at a value. It delivers the worst efficiency because of this huge wetted space. It’s the slowest of the keel sorts, and it has the worst windward efficiency.

This makes full keels notably nice for longtime cruisers or liveaboards preferring consolation over pace, however much less best for daysailers who have to navigate out and in of slips usually.

Because it runs for not less than 50% of the hull, it does not have to run as deep as a fin keel, leading to a extra shoal draft.

Heavier keels lead to elevated displacement, so a full keel boat will want a bigger sail space to compensate for its weight.

For a extra detailed dialogue on full keel benefits, I like to recommend studying William’s glorious article 5 Shocking Benefits of a Full Keel Sailboat right here.

Instance sailboats with a full keel:

  • Nicholson 22
  • Island Packet 380
  • Beneteau Oceanis 411 Clipper
  • Beneteau First 50
  • Jeanneau Solar Shine 38
  • Dufour 455 Grand Giant

There are quite a lot of nice cruising boats with full keel designs, a few of them thought-about classics.

Full Keel with skeg rudder

Full keels with a skeg rudder design have a protected rudder, due to placing a structural a part of the keel straight in entrance of the rudder. This helps with heading off any hazards to the rudder, like floating items of rope, rocks, or rubbish, and protects it in case of working aground. The skeg design ensures the rudder is sort of inconceivable to interrupt off.

Modified Full Keel

  • Fastened keel
  • Good for cruising and liveaboards
  • Sooner than an everyday full keel
modified full keel sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a modified full keel? A modified full keel is a full keel with a cutout on the entrance, decreasing the wetted floor barely, which will increase efficiency with out sacrificing an excessive amount of consolation and stability. After the complete keel, it has the most effective directional stability and the least quantity of heel.

The modified full keel is well-liked amongst (bluewater) cruisers, due to its elevated dealing with and efficiency. Most modified full keels have a skeg rudder, guaranteeing it’s well-protected.

The marginally lowered weight and wetted floor enhance windward efficiency rather a lot, however it’s nonetheless probably the most secure keel designs on the market.

Instance sailboats with a modified full keel:

  • Hallberg-Rassy HR 40
  • Sunwind 27
  • Dufour Arpege 30
  • Beneteau Oceanis Clipper 281
  • Jeanneau Solar Odyssey 37.2

Fin Keel

  • Fastened keel
  • Good for racing
  • Quick
fin keel sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a fin keel? A fin keel is an extended, weighted blade connected to the underside of the hull. It’s lighter, quicker, and extra maneuverable than a full keel, but additionally extra weak. The elevated distance between ballast and sails offers a lever, decreasing the necessity for a big wetted floor or further ballast.

Fin keels are usually bolted onto the hull and run deeper and thinner than a full keel. They’re additionally lighter. This helps rising efficiency (lots), making fin keels lots quicker in all conditions.

There are some main disadvantages to fin keels, nonetheless. Fin keels are lots much less comfy than full keels and permit for extra heel and a much less strong monitor, so much less directional stability. Fin keels are additionally much more weak than full keels. They will break off when working aground, or get broken.

They’re highly regarded amongst racers and carry out higher when maneuvering in tight spots, like getting out and in of slips.

Instance sailboats with a fin keel:

  • Catalina 30
  • Hunter 34
  • Bavaria 40
  • Jeanneau Solar Odyssey 36.2

Fin keel with skeg rudder

Fin keels with a skeg rudder use a small structural half in entrance of the rudder to guard it. This design is generally built-in into the hull, making it much less weak, and an ideal compromise between pace and security.

Fin keel with spade rudder

Fin keels with a spade rudder have a very uncovered rudder, and sometimes a fin that’s merely bolted on. The keel is not built-in into the hull, making it extra weak and fewer comfy.

sailing yacht fin keel under - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Wing Keel

  • Fin keel variant
  • Good for cruising
  • Much less crossflow
wing keel sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a wing keel? A wing keel is a fin keel with a horizontal foil on the tip, which is wing-shaped and customarily weighted. Its form reduces crossflow, bettering directional stability, and its ballast decreases heel, leading to a extra comfy trip. The addition of a wingtip permits for a shorter fin, decreasing draft.

Wing keels are good for cruising since this design improves directional stability in comparison with an everyday fin keel or a bulb keel.

We’ll talk about the wing keel’s benefits and downsides in additional element on this article.

Bulb Keel

  • Fin keel variant
  • Good for cruising
  • Stability
bulb keel sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a bulb keel? A bulb keel is a high-aspect-ratio fin keel with further ballast on the finish, which usually has a bulb or teardrop form. This ballast improves stability and makes use of the gap between power and counterforce as a lever. This design reduces the necessity for a deep fin, leading to a shoal draft.

By putting the burden on the largest potential distance from the power on the sails, you want comparatively little further weight for a similar discount in heel, making bulb keels very efficient for cruising.

This design reduces the wetted space whereas rising the burden of the keel simply barely, which will increase crusing consolation huge time.

Instance sailboats with a bulb keel:

  • Bavaria B/One
  • Enigma 34
  • Beneteau First 24

Bilge Keel

  • Fastened keel
  • Good for racing
  • Will be beached
bilge keel sailboats diagram 2 - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a bilge keel? A bilge keel is a twin keel which makes use of double fins, permitting the boat to be beached and relaxation on its keel upright. Bilge keels have double the wetted floor, which will increase consolation and directional stability whereas reducing heel. Fashionable bilge keels usually present first rate windward efficiency, thanks to higher design.

The bilge keel does sacrifice pace in comparison with the fin keel however does not essentially supply worse efficiency total. Older designs carried out significantly worse than different keels and had been particularly gradual.

bilge keel sailboats diagram 1 - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

Bilge keels have some main benefits over full keels and fin keels. Crucial is that the boat might be beached, making it a preferred design in tidal waters. Bilge keels are particularly frequent alongside the British shoreline, the place fishermen hold their boats in tidal harbors.

One other main benefit is that the boat might be saved resting on its keels, making dry storage and upkeep lots simpler.

After all, there are various extra execs and cons to the bilge keel, which we go into right here.

Instance sailboats with a bilge keel:

  • Dufour Dynamique 62
  • Hunter Duette
  • Patagonia Patago 39
  • Macwester 27
  • Moody S31


  • Lifting keel
  • Good for daysailers
  • Versatile
centerboard sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a centerboard? A centerboard is a sort of retractable keel that rests on a hinge and might be lowered by means of a slot within the hull. It folds out like a pocket knife and means that you can enhance or cut back the draft of the boat. Centerboards are principally used on small fishing boats.

The centerboard is a really versatile keel kind, permitting you to have each a really shoal draft for inland waters, in addition to steadying the boat and decreasing heel for bigger our bodies of water, and even oceans.

I’ve sailed a Cornish Crabber with a centerboard for every week, and whereas we stayed inland, having the choice to extend the keel depth actually got here in helpful when crossing the IJsselmeer (a former sea in The Netherlands).

There’s extra to the centerboard design than we will go into right here. I like to recommend you learn my article on swing keels for an in-depth rationalization of the mechanics and execs and cons of the centerboard keel design.

Instance sailboats with a centerboard:

  • Cornish Crabber
  • Jongert 45C
  • Aquatic 25
  • Antilla 33

There are various extra fashions utilizing this design – we have mentioned 13 of the preferred sailboats with centerboards right here.

Daggerboard Keel

  • Lifting keel
  • Good for daysailers
  • Versatile
daggerboard sailboats diagram - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What’s a daggerboard keel? A daggerboard is a sort of lifting keel, which might be lowered by means of a slot within the hull. It lowers straight down and means that you can enhance or cut back the draft of a ship. Reducing the daggerboard will lower heel and enhance directional stability. This design is generally used on small daysailers.

Due to its simplistic design, daggerboards will not be generally used on bigger boats. You can find them totally on small daysailers and lesson boats. Typically, the daggerboard is a picket board that’s carried within the hull – it is not connected to the hull.


  • Pivoting keel
  • Good for river crusing
  • Shoal draft
leeboards leeuwarden - Sailboat Keel Types: Illustrated Guide (Bilge, Fin, Full) | Coast Swimming

What are leeboards? Leeboards are a type of pivoting keel, mounted to the aspect of the hull, used to scale back slippage to leeward, therefore the identify. Since leeboards are unweighted and do not run under the waterline, they do not lower heel considerably. Leeboards are primarily used for inland or tidal waters.

The benefit of getting leeboards as an alternative of a keel is the extremely shoal draft. Boats with leeboards do not want a keel, to allow them to be flat-bottomed, which is a really secure hull design, so long as the water stays calm.

In troubled waters, you’ll discover the dearth of a keel, which is why they’re used on buying and selling ships for inland waters.

One other giant benefit of leeboards over a keel is the flexibility to seashore the boat. In The Netherlands, leeboards are extensively used on barges that sail the Waddenzee. The Waddenzee has very giant tidal motion, and at any time when the tide retreats, these boats simply lie flat on their stomach.

Instance sailboats with leeboards:

  • Dutch barges
  • Aak
  • Schouw

Canting Keel

  • Moveable keel
  • Good for racing
  • Elevated efficiency

What’s a canting keel? A canting keel rests on a hydraulic canting hinge beneath the boat, which might be moved to windward, utilizing the keel’s place as a lever in countering the forces on the sails. This improves efficiency considerably by decreasing the wetted floor and total weight of the keel whereas rising maneuverability.

Canting keels are principally utilized in high-performance crusing and will not be but used on cruising sailboats, primarily due to the necessity for underwater hydraulics on this keel design. It’s a weak keel kind, with further shifting elements which are tough to restore once they break.

The canting keel is an attention-grabbing design, and the promise of elevated efficiency and maneuverability is seductive. Nevertheless, I believe most cruisers will proceed to choose mounted keel designs since they’re extra dependable.

In crusing, security comes over efficiency. The slight enhance in pace is just not definitely worth the potential draw back of getting to repair underwater elements whereas cruising.

Instance sailboats with a canting keel:

  • Beneteau First 211
  • Dehler Sprinta 70
  • Northshore Yachts Southerly 105
  • Laurent Giles Keyhaven Yawl

Decide the Excellent Keel

In deciding on the right keel for you, there are three primary components that decide which keel is greatest for you. These are the three I’ve talked about above: pace, maneuverability, and luxury.

Every kind of crusing requires completely different traits. Liveaboards will choose stability and luxury above all. Cruisers will prioritize consolation and a little bit of pace. Daysailors want a shoal draft and good maneuverability.

So what keel is greatest for you all comes right down to what sort of sailor you wish to be.

For every scenario, the next keel sorts are usually a protected wager:
  • For cruising, you need a modified full keel or a fin keel with a skeg rudder.
  • Coastal liveaboards in all probability need a full keel, whereas inland liveaboards would possibly choose a flat-bottomed hull with leeboards.
  • Coastal daysailors will usually choose a fin keel with a skeg rudder or a centerboard.
  • For racing, you need a fin keel or wing keel.

What kind of keel is the most effective?

Probably the most secure and dependable keel is the complete keel. It’s the heaviest and longest keel out there, and in addition the least weak. Full keels are absolutely built-in into the hull, decreasing the danger of injury in case of working aground. Its weight ensures most heel discount.

Whereas it relies on how you’ll truly use the boat, full keels are usually thought-about the most effective keels for most individuals. Nevertheless, they’re gradual. For those who’re going for efficiency, I undoubtedly recommend a fin keel.

What’s the most effective keel for offshore crusing?

The very best keel for offshore crusing will likely be a full keel or modified full keel. Full keels lower heel essentially the most and supply the most effective directional stability of any keel kind. These two traits are essential in sea climate circumstances, the place wind power and wave peak can get particularly alarming.

However there are various extra concerns when choosing a bluewater cruiser. Keel design is without doubt one of the most essential components, and we talk about it at size in our article on the most effective keel design for bluewater crusing.

Additional studying:

If you wish to learn on, I like to recommend this excellent article by Yachting Month-to-month (new tab): How keel kind impacts efficiency.

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