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- The keel provides two things: lateral resistance, so that the boat doesn't drift sideways, and ballast, which rights her.<\/li>\n
- A deep keel with heavy weight low down usually sails best to windward, but requires more water depth.<\/li>\n
- Bilge keels, lifting keels and centreboards reduce draught and make drying out easier, but bring their own compromises.<\/li>\n
- For tidal waters like the Wadden Sea, shallow draught matters; for long sea passages, robustness and course stability count more.<\/li>\n
- Running aground can damage the keel invisibly; it should be inspected by professionals.<\/li>\n<\/ul>\n
What does the keel do on a sailing yacht?<\/h2>\n
The keel prevents the wind from pushing the boat sideways, and it keeps her upright. Both depend on shape, depth and weight distribution.<\/p>\n
When wind presses into the sail, the boat wants to slip sideways and heel, i.e. lean over to one side. The keel surface acts like a wing underwater and keeps this sideways drift, the leeway, small. At the same time, there is ballast in the keel, usually cast iron or lead. The lower this weight sits, the more strongly it rights the boat. This creates the fundamental conflict of all keel shapes: draught brings performance and stability, but costs freedom of movement in shallow water.<\/p>\n
What keel shapes are there for sailing boats?<\/h2>\n
The main keel shapes are long keel, fin keel, keel with bulb, wing keel, bilge keel, and movable keels such as lifting keel, swing keel and centreboard. There are also hybrid forms such as the keel-centreboard.<\/p>\n
Long keel<\/h3>\n
With a long keel, the keel extends along a large part of the hull length, often all the way to the rudder. The boat therefore tracks very straight and responds benignly to waves from the side. The price for this: a long keeler turns sluggishly, needs more momentum when tacking and is difficult to steer astern in harbour. The large area underwater also slows her down in light winds. Long keels are mainly found on older cruising yachts today.<\/p>\n
Short keel or fin keel<\/h3>\n
The fin keel is a narrow, deep plate beneath the middle of the hull, with the rudder hanging separately further aft. This design is common on modern cruising and charter yachts. She turns quickly, manoeuvres well in harbour and sails close to the wind. In return, she demands more attention at the helm, because the boat tracks less naturally in a straight line.<\/p>\n
Keel with bulb (T-keel or L-keel)<\/h3>\n
Here a thickened ballast body, the bulb, sits at the lower end of a slender keel fin. If the whole thing looks like an inverted T from the side, it's called a T-keel; if the bulb only projects aft, it's an L-keel. Because the heavy weight is right at the bottom, less ballast is needed for the same righting force. An example from builder's specifications: the Hallberg-Rassy 370 has a lead bulb on an iron fin and 2.00 metres draught. The version with roughly 31 centimetres less draught carries a good 500 kilograms more weight, because shallower ballast has less leverage.<\/p>\n
Wing keel<\/h3>\n
The wing keel is a rather short keel with lateral wings at its lower end. The wings bring additional weight far down and are intended to reduce the vortices at the keel tip that otherwise cost performance. On cruising yachts, the wing keel is often used as a shallower keel option. The principle became famous through the Australian racing yacht Australia II, which won the America's Cup in 1983 with such a keel.<\/p>\n
Kimmkiel<\/h3>\n
A bilge keeler has two keels, which sit at an angle under the hull on port and starboard. The boat can thus stand upright on her two keels at low water without toppling over. The draught is less than with the single-keel version of the same model: the RM 1180 from French builder RM Yachts has 2.25 metres with one keel, 1.95 metres with two keels.<\/p>\n
Lifting keel and swing keel<\/h3>\n
With a lifting keel, the ballast keel can be raised vertically; with a swing keel, it pivots aft and up about an axis. Both usually work with hydraulics or a winch. The great advantage: lowered, the boat sails almost like a fixed-keel yacht; raised, she can enter shallow bays, river mouths or can dry out. Some models are available with either fixed or movable keel.<\/p>\n
Centreboard and keel-centreboard<\/h3>\n
On a centreboard boat, the keel is a movable plate that carries hardly any ballast. It mainly provides lateral resistance; stability must come from ballast in the hull and the hull shape. Ocean-going yachts of this design achieve very little draught with the centreboard raised: the Ovni 430 from Alubat has 3.45 metres with the centreboard down and 0.98 metres with it up; the Allures 45.9 has 2.90 and 1.12 metres. Such boats often have twin rudders so that they remain manoeuvrable even when heeled and with the centreboard raised. A keel-centreboarder is the hybrid form: a short, fixed ballast keel from which a centreboard extends downwards.<\/p>\n
Keel shapes compared<\/h2>\n
The table shows typical tendencies. In individual cases, hull shape, weight and construction matter more than the label.<\/p>\n
![\"Hull](\"https:\/\/www.toernfinder.de\/wp-content\/uploads\/2026\/10\/kielformen-winterlager-1024x683.jpg\")
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