Re: Technical: heels on foot plate?

paul_v_smith@xxxxxxxxxxx wrote:

I think that Mikes example of just sitting and rolling back and forth
on the seat explains that nicely. As you draw yourself toward the
catch, which happens very shortly after the release the hull
accelerates forward relative to our body mass, since the hull + drag is
a fraction of our body mass.

Careful, don't go adding force and mass. Can't be done. ;^)


Here is where Mikes exercise gets tricky, since the hull drag is not
fixed, the direction which we move our body mass the most quickly
realtive to the hull, will be the direction the COM of the system
begins to move. i.e. move through the recovery very quickly and then
the "oarless drive" slowly, the system will be moving slowly
sternwards.

I think you have that backwards. Oars out and above the water, quick recovery, slow "drive" and you'll inch your way in the direction the bow points, not sternward. On the quick "recovery" you surged the hull forward. Then, you ease to a stop at the sternstops, and at the same time stop some/all forward movement of the hull. Then, ever so slightly, you slowly extend the legs. With almost zero acceleration of your body as you move toward bow, there is almost zero force applied to the boat, so the friction between boat and water is enough to keep the hull almost stationary, it's enough to counter the small force you're applying to the foot stretchers. So, the boat moved forward on your "recovery" and didn't move (not much anyway) on the "drive", so you've got a net displacement in the bow-ward direction.

Do both equally and the system will be stationary.

If you're perfect. ;^)

-Kieran
.

Relevant Pages

  • Re: Technical: heels on foot plate?
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  • Re: Technical: heels on foot plate?
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  • Re: Technical: heels on foot plate?
    ... I think that Mikes example of just sitting and rolling back and forth ... accelerates forward relative to our body mass, since the hull + drag is ... a fraction of our body mass. ... phase there was more force produced in the sternward direction causing ...
    (rec.sport.rowing)