How to Choose Between a Rudder and Skeg
Disclaimer: I have deliberately avoided the use of certain nautical terminology and opted when appropriate to use laymen’s terms. The purpose of this article is to provide easy to follow information that may be of use to the novice in choosing between a rudder and skeg. The use of nautical terminology has its place in sea kayaking but would only hinder the novices for this particular discussion.
Most anyone in the market for a Touring Kayak (a.k.a. Sea Kayak) will inevitably be faced with an important choice: Rudder or Skeg? These days just about every touring kayak or sea kayak comes with either a rudder or a skeg. Why do some sea kayaks (touring kayaks) come with rudders and others come with skegs? What is the difference, in terms of distinguishing characteristics and overall functionality between a rudder and a skeg? What is the purpose of a rudder or a skeg in a touring kayak? If we compare and contrast rudders with skegs, does one choice have any advantages or disadvantages over the other with regard to sea kayaks or touring kayaks? In this article, I will attempt to address these questions so that the reader is better able to make an informed choice regarding the rudder vs. skeg option.
What is a Rudder?
The rudder line allows the rudder blade to be lowered (to deploy) or raised (when not in use). The other end of the line is attached to a cleat that is usually mounted slightly behind the paddler. This line is controlled by the paddler’s hand. The rudder cables allow the blade to turn right to left (which causes the boat to turn right or left). These cables are connected to the footbraces inside the kayak. Thus, the boat can be “steered” by using one’s feet.
What is a Skeg?
In the case of an Internal Skeg, the blade is located in a recessed housing underneath the kayak. The skeg blade is connected to a metal cable that runs inside the boat to a sliding lever that is usually located beside the paddler. This sliding lever is controlled by the paddler’s hand. This slide will allow the skeg blade to be extended into the water (to deploy) or retracted into the boat (when not in use). In the case of an External Skeg, the blade is mounted in the same manner as a rudder, except there are no cables to turn the blade right to left (that is, the bade will only go up and down).
The principle mechanical difference between a rudder and a skeg is that the skeg goes up and down (but not side to side), while the rudder goes up and down as well as side to side.
What is the purpose of a rudder or a skeg in a sea kayak?
When a boat is being paddled in a forward direction, a wave will form at the bow (front) of the boat. This bow wave is a natural consequence of the energy from the movement of the kayak being imparted to the water in the form of a wave. The faster you go (or the more blunt the bow), the larger this bow wave becomes. The bow of the boat sits right in the center of this bow wave and as you paddle forward the tip of the boat will attempt to plow this wave into a “V” shape. The effect of all this is that the bow wave tends to hold the front of the boat stationary –as though the very tip was sitting in a “V” shaped notch.
Every displacement craft will have a bow wave.
You might be wondering why you need to know this. Here’s why:
Let’s say you go paddling on a windy day and the wind is coming in from your right. Thus, there is a force trying to move the boat to the left. If you are trying to paddle forward under these conditions, a bow wave will form that will want to “hold” the bow in place. In other words, the bow wave will provide some resistance to the force of the wind on your boat. The stern (rear) of the boat has no such resistance and it is relatively free to pivot and move around. Consequently, the bow of the boat will be held in place (by the bow wave) and the wind will blow the stern down wind (in this case, to the left). In other words, the bow will want to point right. Simply put, the net effect of all this is that on a windy day, a boat will want to turn towards the wind -a phenomenon known as weather-cocking.
If you are trying to make your boat go straight while the wind is coming in from the side (Beam), then you will need to deal with weather-cocking. This is one of those things you need to experience to truly appreciate. The wind has tremendous power and can be quite frustrating to a sea kayaker. There are a number of ways to deal with this weather-cocking problem.
One option is to attempt to overpower the effect of the wind by simply taking sweep strokes on the side the wind is coming from. The strategy here is to attempt to turn the boat back downwind by sheer brute force. Needless to say, this is not a particularly elegant strategy and it will tire you quickly.
Another option is to edge the boat into the wind. Most sea kayaks have hulls that perform differently when leaned over or placed on edge (in comparison to when they are paddled flat with no edging). British style sea kayaks in particular have a radically different “footprint” in the water when they are edged as opposed to when they are paddled flat. Paddled flat, all sea kayaks have a “foot print” that is shaped something like a straight line segment. This means that the boat will want to go straight (unless the wind is trying to turn it) on its own. Paddled on edge however, many sea kayaks (British style ones in particular) have a footprint that is shaped more like a “C” shaped curve. For example, when one of these kayaks is edged to the right, the footprint curves to the left. This behavior allows the boat to be much easier to turn to the left when the boat is edged to the right. Thus, if you tilt the boat into the wind, you will be better able to turn the boat away from the wind. This technique is called a J-Lean. This name comes from the shape that your spine resembles (a “J”, in this case) when holding this position.
J-Leans work fine with a sea kayak that behaves differently enough when edged. The only problem is that J-Leans are tiresome to maintain for long periods of time. For example, if you are doing a 12 mile paddle with a consistent wind coming in from your right, you would need to maintain a right J-Lean for the next 3 hours required to cover this distance. All the while, you would be taking a lot of sweep strokes on the right. If you do this enough, you will want a better solution.
Another option is to choose a sea kayak that has a stern with a built in keelson. A keelson is a hull feature that is like having a fixed blade in the water at all times. It is similar to having a keel, except it is found only on the stern of the boat. This keelson provides some resistance to being pushed sideways by the wind. Though popular with some purists, sea kayaks with keelsons are difficult for the average paddler to maneuver, since it requires so much effort to move the stern around. What most folks really need is a “keelson” that is normally retracted but can be deployed when needed.
This is precisely the idea behind the skeg. Imagine this scenario: You are paddling forward at 4 knots and you have a 15 knot wind coming in from your right. Your bow wave keeps your bow from getting blown downwind but your stern is still getting pushed downwind. Pretty soon, you are weather-cocking to the right. You decide to slide your skeg down an inch or so. The stern of the boat now has a little more resistance to being moved downwind and so your boat starts to turn to the left a little bit. However, the bow wave is still holding the bow in place more firmly than the skeg is holding the stern. Consequently, you are still weather-cocking to the right –though not as much as before. You decide that you require more correction and drop the skeg down 4 inches. Now, the stern is held in place even more strongly than the bow and the bow starts to turn downwind sharply to the left. You quickly realize that you need to dial in the skeg about half way, about 2 inches in this case. The sea kayak is now in equilibrium; the resistance to wind at the bow (created by the bow wave) equals the resistance to the wind at the stern (created by the skeg). The boat now tracks where you point it! It is important to understand that a skeg is an incremental correction device –it is not just “on” or “off”. Furthermore, the skeg only has value on a windy day; you can’t make a sea kayak turn by using the skeg if there is no wind. Note that this is perhaps the most important distinction between a skeg and a rudder.
In the case of a rudder, let’s consider the same scenario as above: You are paddling forward at 4 knots and you have 15 knot wind coming from the right. Your stern starts to blow down wind and your sea kayak starts weather-cocking into the wind towards the right. You decide to deploy your rudder. Using your feet, you adjust the orientation of the rudder until the stern is “steered” back upwind. Your sea kayak is now tracking where you point the bow.
In both the case of the skeg or the rudder, you are using the device to compensate for the force of the wind. The longer the boat, the greater the leverage created by this wind force on the paddler (this is why shorter boats can often get away with neither skeg nor rudder). A rudder blade deflects water in a particular direction, causing the boat to turn; a skeg creates resistance to the turning affect caused by the wind and causes the boat to go straight. In both cases, the devices are being used to make a boat track straight when the wind is trying to make the boat turn. Note that this is how the device should be used. It is possible to use a rudder to simply “steer” the boat using your feet, regardless of wind. This is a “technique” used by some beginners to make their boat turn if they do not know how to do a proper sweep stroke. Most experienced paddlers will use these turning strokes to turn their boat, while using the rudder or skeg to compensate for the effects of strong winds. While the goal of both the rudder and the skeg is the same, the operating characteristics are somewhat different.
Why do some touring kayaks come with rudders while others come with skegs?
Some sea kayaks have a very strong tracking component; the hull has little rocker towards the stern. Additionally, these types of boats often do not change their footprint in the water substantially as they are edged and are generally not regarded as particularly maneuverable. Sometimes referred to as Northwest style sea kayaks, these boats are known for their tracking ability and predictability in varied conditions. Generally, a Northwest style sea kayak will track well and be relatively more difficult to turn. Rudders have a very strong corrective component; you can deflect a tremendous amount of water with a rudder. In the case of a boat that is difficult to turn (or tracks particularly well, depending on your perspective), a rudder makes the most sense because it will have a strong enough corrective component to make this relatively stationary stern move around.
On the other hand, certain sea kayaks have very maneuverable hull designs. In some cases, the kayak has significant stern rocker, which makes the stern relatively free to move around. In many cases, these boats also have hulls whose footprint changes substantially when edged, making them “lively” and responsive. Sometimes referred to as British style sea kayaks, these boats do not require rudders to make the stern move around. Instead, these boats make good use of skegs to keep their relatively free moving sterns more stationary during windy conditions.
Generally, a well designed Northwest style sea kayak will come equipped with a rudder while a well designed British style sea kayak will come with a skeg. However for marketing reasons, some manufacturers will slap a rudder on every touring boat designed for a beginner since they perceive ruddered boats to be easier to sell than skeged ones. Still, there are some important differences in terms of advantages and disadvantages that you might want to be aware of.
What are the advantages or disadvantages of skegs or rudders?
In my opinion, here are some advantages for skegs:
- Fewer moving parts equals less to go wrong
- When not deployed, the skeg has no surface area to expose to the wind
- Footbraces do not move so you can push hard with your feet while bracing/paddling
- Generally has less drag than a rudder when deployed
Here are some disadvantages for skegs:
- Has less corrective ability than a rudder (though this should not matter if it is on the right hull)
- Skeg cable can sometimes kink and make the skeg difficult to deploy/retract
- Skeg box requires good workmanship to avoid leaks
- Skegs can’t “steer” the boat when there is no wind
- Skegs are less intuitive to understand
Here are some advantages for rudders:
- Has an extremely strong corrective component that can overcome high winds and lack of skill
- Rudders are very easy for beginners to understand and use
- Can be used to “steer” the boat, regardless of wind. This could be a big advantage if you have your sea kayak set up with a hand operated sail
- Rudders are almost a necessity in a tandem sea kayak, which is generally very difficult to turn otherwise.
Here are some disadvantages for rudders:
- Usually have slightly more drag than a skeg when deployed
- May lead some beginners to never developing good turning/boat control strokes
- Most designs create some slack in the foot pedals which can be noticeable under certain conditions
What conclusions can I draw from all this information?
Probably the most important concept to understand is that most people will find either a skeg or a rudder to be beneficial in a touring boat. The longer the boat, the more important it becomes for most folks to have some help with windy conditions. The next most important thing to understand is that both rudders and skegs are designed to help the boat go straight when the wind wants to make the boat turn. Finally, one should realize that certain sea kayak designs lend themselves better to a rudder application while other designs work better with skeg applications. In general, a relatively maneuverable and responsive touring kayak (that does not track like a cruise missile) will function best with a skeg. Conversely, a touring kayak that tracks like it is on rails (and is more difficult to maneuver) will benefit most from a rudder. Thus, the choice between rudder and skeg really comes down to what type of handling characteristics one wants out of a sea kayak. If you still have no preference, than consider some of the advantages and disadvantages listed above. Better yet, come to one of Great Outdoor Provision Co’s on water boat demos and try both types of sea kayaks. Armed with the information in this article, I’m confident you will be better able to make a clear choice once on the water.