Paul Caffyn on rudders and skegs
Länken till Paul Caffyns klassiska roderpredikan verkar inte fungera längre, men flera av hans artiklar är återpublicerade lite här och var på internet (den här är från expeditionkayak.com). Sidan är länkad från Utrustningssidan, där jag diskuterar för- och nackdelar med roder.
By Paul Caffyn
During my very first sea kayak expedition around Fiordland in 1977/78, Max Reynolds and I used small retractable skegs that were attached to a ‘shoe’ or fibreglass sleeve that slid over a Nordkapp stern. Only the size of a cigarette packet, the skeg was rotated into position in deep water by the other paddler. It evolved during the South Island trip into a deep shark fin shaped skeg, mounted on a ‘sleeve’ that sat loosely on the stern for launching and was pulled into position with a cord from the cockpit. Shock cord, from the stern to the skeg, allowed the skeg to ‘retract’ out of the way for landing. For following, or quartering seas from the stern, the skeg improved the kayak’s tracking in a straight line. For the start of the Australian trip I used an HM Nordkapp, with the extended keel stern, but after a gripping experience of being unable to turn up-wind on a flat sea in gale force winds, I cut the extended bit off and reverted to using my shark fin skeg.
Prior to the trip I was intrigued by the deep draught, over the stern fibreglass rudders that the Tasmanian paddlers considered not as optional extras but as integral parts of their boats. Photographs of the seas they paddled and accounts of long distances achieved with rudders in diabolical conditions, led me to thinking about trying a rudder. When I broke the skeg blade off south of Brisbane, a friend helped me build a sturdy Tasmanian style rudder out of aluminum. Still with a mind set about kayaks and rudders, we mounted the rudder on a fibreglass ‘shoe’ or sleeve, that slid over the Nordkapp stern, and was held in place by the deck lines. Well, the mind set disappeared with the first long surfing run north of Brisbane, and the rudder stayed in place for the rest of the trip. It saved my life on several occasions, the most crucial being the overnighter along the Baxter Cliffs when I was caught by a savage cold front. When I limped into a beach at the end of that 106 mile drama, my knees and heels were rubbed bare of skin down to the exposed blood vessels, such was the battle to steer clear of being smashed into the vertical cliffs.
The statistics speak for themselves in showing the benefit gained from the addition of a rudder: Melbourne to Sydney:
- HM stern – 30.6 miles per day Sydney to Brisbane
- Skeg – 34.3 miles per day Brisbane to Cape York
- Rudder – 39.2 miles per day
Contrary to the notion of a rudder being: ‘not for steering, but to trim. Sea kayaks are steered with the paddle, like all kayaks and canoes.’ I use my rudder for steering – the paddle solely for forward propulsion. When a paddle is used for corrective steering strokes, either sweep or paddling on one side, forward propulsion suffers and the normal paddling cycle is upset.
I must qualify this and state the design, structure and mounting determine the difference between inefficient and efficient rudders. My rudder blades project 12″ below the keel line. I have never broken a rudder – bent the blade once off North Queensland in a big surf, but straightened it out over my knee on shore and it was good for another 6,000 miles.
Situations where I have found a rudder to be invaluable include:
- manoeuvring in congested sea ice or iceberg choked seas
- ferry gliding across channels with fast tidal streams
- coping with boils and eddies in overfalls
- steering when the wind is too strong to paddle
- fast manoeuvring in congested shipping lanes
- hugging a reef fringed coast when paddling into a strong tidal stream flow
- surfing in front of following seas
Another advantage of a sturdy deep draught, over the stern rudder is a surprising increase in overall boat stability.
The most magic sound I hear at sea is a humming vibration generated during fast surfing runs at 15 knots+, either when surfing boat wakes or in front of following seas. Sheer magic!
© Paul Caffyn, 2000