KASK Membership• Only $35/year
• 6 Newsletters a year
• Forum & event invitations
The Daggerboard Rudder
This concept was designed by Don Currie in the early 1990s. Two New Zealand manufacturers then produced variations of it and they were fitted to Challenge Plastics and Norski Kayaks. A decade later, KayakSports designed a version, the Navigator, found on Riot kayaks in New Zealand. A decade after that Sea-Lect supposedly patented it.
If a rudder extends well below the hull when you are in deep water, when you come ashore you need to be able to retract it. The most common form of retractable rudder is the Over-the-Stern type. The blade pivots 270 degrees from its vertical deployed position to a horizontal retracted position on the aft deck. The Daggerboard Rudder system departs from that design. It goes from vertical to horizontal the short way, by pivoting 90 degrees. When you pull on the retracting line, attached to the top of the blade, the blade slides within a pivoting sleeve and comes ‘blade-top’ first, on to the aft deck.
This shows the action of the rudder and is not a good version of it or kayak design.
Don Currie’s design provides a couple of significant advantages. The rudder is self-centering as it retracts, as the retraction line feeds through a guide on the centre line of the aft deck. With an Over-the-Stern rudder the rudder pedals have to be centred when the rudder is retracted and hopefully, the rudder blade will land in the V-block on the deck. If not centred, the rudder will come to rest off centre, dangling over the side of the kayak.
The Daggerboard Rudder comes aboard gracefully, slithering up on deck. The over-the-stern type often comes down with a hard thump.
It functions just as well as other rudders: It extends far enough below the hull to reach past the turbulent water around the hull, and it kicks up and drops back as the kayak passes over obstructions.
When the dagger-board rudder is retracted, the rudder and the rudder pedals are locked in place by the top of the rudder being locked to the pull-up line-guide holding it central. The stiffness of the rudder pedals is a function of the cables and the type of rudder pedals, not of the rudder and its position.
Some variants of the design (Challenge Plastics and Kajak-Sport) use a bungee cord to pull the rudder blade aft and launch it when you release the retraction line. After the bungy cord has done its job, the weight of the outboard end of the blade makes it pivot and drop into the water. The SeaLand Kayaks version uses a pull-down line for positive action. To raise the rudder, the toggle is pulled forward and latched in the locked-up block. To lower the rudder, the toggle is released and the pull-down line pulled forward.
On one version, KajakSport’s Navigator rudder, the pin that allows the rudder to pivot (pintle) is retained in the rudder gudgeon by a flat-head machine screw and a washer for a stop. The sensible design uses a split ring (like a key ring). It is field serviceable and won’t come loose and fall off as can happen with the screwed version.
Like a lot of good designs, it is simple and functions without the user having to give it much thought.
A mock-up of the rudder was first shown by Don Currie at a KASK forum in Christchurch in 1992, along with his rudder pedals with auto-adjusting rudder lines.
Commercially, a variation of the original design was first attempted by TopSport in Christchurch. Challenge Plastics Ltd, Kerikeri, NZ developed theirs and used it on the Breeze kayaks. Another variant was tested on a double, which later circumnavigated Vanua Levi, Fiji in 1994, and this version of the design was supplied to Norski by SeaLand Publications, Kayak Division, and fitted to Norski Seaward F singles and Gemini II doubles.
Over a decade later KajakSports produced the Navigator version and this is used by Riot on some of their sea kayaks. The most recent version is by Sea-Lect Designs in 2009. Both KajakSports and Sea-Lect claim to have patented it though their claims would most probably fail if covering the concept and not just minor parts of the idea.
Design details to follow soon.
For further ideas also look at:
This includes the Side-mounted or Southern Viking rudder.
Interesting is the Viking rudder. This was devised in Australia in 1985. About a decade later Don Currie in New Zealand also designed a very similar system. When Sandy Ferguson first saw it he christened it the Southern Viking Rudder – all this before the Australian one was known about and which they’d called the Viking Rudder!
KASK's aims are to:1. Promote and encourage the sport of sea kayaking
2. Promote safety standards
3. Develop techniques and equipment
4. Deal with issues of coastal access and protection
5. Organise sea kayak forums around the country
6. Publish the Sea Canoeist Newsletter and the KASK Handbook