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| Figure 1. Weather-cocking vs. Lee-cocking |
Yes, lee-cocking (turning downwind) in beam winds is
a thing. Some kayakers haven't experienced lee-cocking since most sea kayaks are designed to reliably do the opposite - weather-cock (turn towards or into the wind) to varying degrees. Kayaks are made to weather-cock because this
effect of turning into the wind can be countered by dropping a skeg
located at the stern of the boat. In
this way, paddlers can keep their boats going straight in a range of
conditions. No wind – minimal use of the
skeg. Increasing wind – increasing amount of skeg deployed.
I’ve owned kayaks that weather-cock a lot and those that
only do so when winds pick up. Generally speaking, kayaks with more “rocker” (the amount of curvature in the bottom of the hull along its length from bow to stern) weather-cock more. My Valley Pintail and Avocet sea kayaks were in
the “weather cocks a lot” category, and sure enough had a lot of rocker. My
NDK Explorer and Romany were in the “weather cocks a little” category, and in
truth I rarely used the skegs in these two boats since a little edging was
typically all that was needed to stay on course in winds. [By the way, if your kayak has a foot-operated rudder, the tendency of its hull to weather-cock or lee-cock is immaterial - a rudder can make any boat go in any direction. But beware, boats designed to be used with a rudder may be hard to keep straight without it (interesting link about removing a rudder on a ruddered boat).]
Kayaks that don’t weather cock strongly can sometimes do
the opposite when wind and waves get big – they Lee-Cock. This effect cannot be
corrected with a skeg, deploying a skeg will just increase the lee-cocking. If you’ve experienced lee-cocking you know it
can be annoying or alarming depending on your situation! What contributes to Lee-cocking?
Center-of-Mass and cockpit location:
Kayaks weather-cock because the act of paddling forward
creates higher water pressure on the bow as compared to the stern. The bow is locked-in by this higher pressure
and the stern is loose (or looser) due to the lower pressure. Wind can then push the loose stern more than
the locked-in bow causing the kayak to effectively turn into the wind while
underway - weather-cock.
The location of the center-of-mass can have a sizable effect
on weather-cocking and lee-cocking as it will further “lock-in” whichever end (bow or stern) has
more weight. Expedition paddlers know all about this because balancing the weight of their gear, fore-and-aft,
will affect how their boat responds to wind. But if
you’re (like me) mostly a day-paddler, your body is the main “load” in the boat and then
the location of the cockpit comes into play.
I’ve experienced alarming lee-cocking a few times in two boats in particular - my NDK Romany and the Tiderace Xtreme. Both boats are pretty
directionally neutral in mild/moderate winds. But when conditions get bigger,
they both can lee-cock in a cross wind. Why? A big factor is because both boats have their cockpits placed somewhat towards the stern. This helps them track straight in following seas and makes them fun
to surf. But with the center-of-mass located somewhat
towards the stern, the pressure on the bow is reduced during forward paddling, it is looser – and lee-cocking can result.
Figure 2 illustrates this effect by imagining kayaks
with their cockpits located way at the bow or way at the stern. The Romany and
Xtreme kayaks are (a tiny bit) like the boat with the cockpit at the stern.
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| Figure 2. Cockpit (center of mass) effect on Weather-cocking and Lee-cocking |
If you’re confronted with lee-cocking when
on-the-water, the first remedy is simply to scooch forward in your seat and
lean forward some to move the center-of-mass towards the bow. Even an inch or two helps. This will lock the
bow in a bit more and loosen up the stern some, reducing lee-cocking. This always worked for me in the
Romany.
Another factor to consider - the lee-cocking effect will occur less frequently for strong paddlers who propel their boats faster, since the pressure on the bow generated by a 3-knot paddling speed is less than at a 5-knot speed. More speed = more water pressure on bow = bow is more locked in place = less lee cocking. By the same token, a paddling speed that keeps the boat going straight in 10-knot winds may not be enough to prevent lee-cocking in 20-knot winds.
Windage:
Windage, or the surface area of boat (and gear) exposed to
the wind, contributes as well. If the surface area of your kayak is much bigger in the front as compared to the back, this unequal windage may make the boat prone to lee-cocking. More commonly, gear stored on the deck can exacerbate
lee-cocking and weather-cocking. In the case of lee-cocking, move any
paddles and other items stored on deck that increase windage from the bow to
the stern. This will reduce the “push” of the wind on the bow and increase
it on the stern. If weather-cocking, do
the opposite. Moving deck gear around is
a lot easier if you’re paddling with others.
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| Figure 3. Move gear to reduce Lee-cocking |
Lastly, waves hitting a kayak from the windward side seem (to me) to
add to the lee-cocking effect of winds. Not sure why this is but, in my
experience, it seems to be true. Perhaps waves have more of a pushing down-wind
effect on the bow for the same reason that forward paddling adds water pressure at
the bow – the bow is locked-in by this pressure so perhaps the wave forces are
transmitted more at the bow than the stern (?). That’s just a guess.
Hope these observations make sense.
