A Kayak rudder is almost always retractable: They’ll extend well below the hull when you are in deep water, and when you come ashore, you can get the blade out of the way so it won’t get hung up on the bottom. Most commercial kayak rudders are made of heavy stainless steel or more commonly of cheap anodized aluminium.
Rudders are useful to counteract the effects of wind and currents but are easily damaged if struck by a following kayak. Making a solid graphite rudder with full size and accurate rudder plans is a fun little project that anybody can do and learn a few things about composites and high tech fibres as well. The rudder construction requires only a few basic tools that every do-it-yourselfer has (drill, hack saw, jigsaw, sandpaper etc. Only a minor adjustment with a file or belt sander is needed on the rudder body to fine tune the retracted and deployed position of the blade.
Most commercial kayak rudders are made of heavy stainless steel or more commonly of cheap anodized aluminium. Kayaks equipped with rudders have movable foot braces that rotate the rudder side to side. Often Day-Touring kayaks come with an optional foot-controlled rudder. Expedition kayaks will definitely come with a foot-controlled rudder as an option and can often be purchased with deck mounted compasses too. With an over-the-stern rudder, you have to take your best shot at setting the rudder pedals even when you retract the rudder and hope that you get the rudder blade to land in the V-block on the deck. If you don’t, the rudder will come to rest off centre, and your rudder pedals will not be even with each other. It’s the most common form of retractable rudder. As long as the retraction line is anchored along the kayak’s centre line, the rudder will come to rest properly lined up on the aft deck.
The Navigator rudder not only finds its way home automatically, it also comes aboard gracefully. It is available in a number of configurations to fit the various standard rudder fixtures. I think the Navigator rudder is an interesting and useful step in the ongoing evolution of kayak rudder design. The best thing about the Navigator rudder is how well it works when it is not needed. When the rudder is retracted, there are deck fittings available to lock the rudder and, to some degree, the rudder pedals in place. The stiffness of the rudder pedals is a function of the cables and the type of rudder pedals, not of the rudder. A bungee cord pulls the rudder blade aft when you release the retraction line. If the bungee cord needs to be replaced, the crimp can be reused or the bungee cord and the retraction line can be run through the hole in the top of the rudder blade and jury-rigged with stopper knots.
Kayak rudders are great for compensating against wind and current, allowing you to use your paddle for forward momentum instead of steering.