Today’s training ride was to get a feel for my ‘race configuration’ speed and make a decision rudder or not to use the new bigger rudder or my tiny knife blade. Contrary to what you see in these photos, the water was NOT calm. 4 to 5 inch waves with a 10 wind, but at least it was consistent for the test.
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2-3 inch waves, large rudder, 120 watts = 10.3 km/hr
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2-3 inch waves, small rudder, 120 watts = 10.4 km/hr
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3-4 inch waves, small rudder, 170 watts = 11.7 km/hr
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4-5 inch waves, large rudder, 170 watts = 11.6 km/hr
.1 km/hr works out to a whopping 2.4 km over 24 hours, but since I am killing myself for every single kilometer, I guess that the small rudder will stay. The reason I am testing out a slightly larger rudder is because I need to stay tight to my buoy marked course. The small rudder won’t allow me to turn as tight as I need. The alternative is to go back to my flip-down kayak rudder that I stole from my Mirage drive Hobie Adventure.
The flip-down unit weighs 1.8 pounds and is only used when making a turn. When I am going straight, I use my small rudder to keep on track. I calculated that the weight of the flip-down rudder would cost me about 1.5 km over 24 hours which is less than the 2.4 km cost of having a larger rudder permanently in the water all the time.
I am splitting hairs here, as there is only a .9 km difference between the two approaches. I guess the deciding factor will be that if I go with the flip down rudder I have a built-in back-up for my rudder if something were to go wrong – like if my regular rudder just fell off or dissolved into thin air or got eaten by the Ogopogo or something.
Anonymous on August 28, 2008
A very small rudder that comes down in the left or right floats will turn you fast as you want.
You could have it at a set angle and size just for your turns.
Bryon Howard on August 28, 2008
Will you feel more confident and comfortable with the bigger rudder?
For example, what if the wind picks up … for a couple of hours … will you be certain that you can even turn up into the wind to make a corner.
Could the small rudder 'screw' the day?
In the last 1 to 3 hours of a 24 hour attempt … if you are down by 1.5km … I think you would find the energy to pick up the wattage to break the record.
Certifiable on September 1, 2008
If you endure several hours of high winds and significant chop, I agree with Bryon that the smaller rudder could prove disastrous when doing turns into the wind. It will also cause more drag as you attempt course corrections during straight runs. Even in flat water and no wind, a smaller rudder does create more drag when correcting course or turning a corner. Its only advantage is on long straight runs with little or no turning. Given the miniscule drag difference between rudders, its main function of directional control should be paramount. Go with the larger rudder and eliminate rougher weather control issues.