Simple skeg system

Senast uppdaterad den 28 maj 2016, 4 kommentarer

The skeg system has been in use for eight years on my Njord and has never given me any trouble. It is a NACA foil and very efficient. It is easily repaired anywhere without any tools: a spare blade or new lines can be fitted in minutes – pull the skeg vertical, pull it aft and it is free. The 3 mm gap between box and skeg is of course not hydrodynamically ideal but keeps the skeg from getting stuck with sand. The foam washers keep the skeg clatter-free in waves and keep the system friction where it should be – on the skeg, not the lines, thereby ensuring that the lines do not jam in the box. The one disadvantage this far is that it is a bit highly “geared” – meaning that the control line travel just 5 cm between up and down, making precision adjustments a bit tricky. But it is not a big issue – in a situation you tug on the line and 95% of the problem is gone. The fine adjustment can be done later when things calm down. The skeg is built on a plywood core to stabilize the perimeter and the pulley part. The center areas of the blade are filled with foam to keep the weight low. The box is thin hardwood pieces between 4 mm plywood sides – or a more elaborate fiberglass box. The brass tubes I used on the prototype, is perhaps better replaced with suitable tube fittings (the best kind of low friction tube is made of a plastic that is very hard to glue).

Björn

Kommentarer

1 Micke Vilen
2016-06-08 19:40

Clear pictures of the simple skeg system. Do you have any pictures on a through the deck skeg system. Or any good source where I could find some info. I guess this kind of system would be less sensitive to get stuck.

2 Björn Thomasson
2016-06-09 07:55

I have outlined the concept of a very simple skeg in the printed manual. My intention is to provide a more detailed suggestion of this as well (like the one above) but as a habitual "tidsoptimist" (time optimist), I don't always find the time to do what I think I have the time to do. Here is a link though...

Since the system outlined above has the system friction in the skeg and not in the lines, it never jams from being forced in (like wire systems do). The only risk of jamming comes from sand or mud forced into the skeg box opening – but that is a risk with every aperture in the bottom, regardless of technique. My solution to avoid this is to widen the gap to 3-4 mm both sides of the skeg – not ideal for hydrodynamics but reducing this risk. Besides, the two-line system has the advantage of pulling down the skeg (instead of pushing as in a wire system), which can sometimes force the skeg down when jammed.

3 Johan R
2017-06-09 10:46

Hej,

Hur lång skall själva skäddan var i en sån här konstruktion?

Mvh Johan

4 Björn Thomasson
2017-06-09 14:28

De kajaker som är tänkta för skädda, har en skädda i rätt storlek på ritningen – bara att mäta, skala 1:10.

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