: The physics involved with a baidarka are exactly the same
: as for any other kind of kayak. If you make the shape below the water the
: same, the boats will handle flat water exactly the same regardless of the
: shape above the waterline.

On, or maybe two caveats.

The first is that water is almost never really flat, so surface motion is a factor in the real world.

The second is that most discussions of hull design are meant to deal with rigid hulls, and the computations for any allowances for flex are probably too complex to master.

Yet, some boats have very flexible "backbones" and deform their shape in response to water pressure. Meanwhile, other boats are very stiff, and, if they have enough displacement they will bridge the gap between two waves, or, if they do not have the displacement, they will punch through the waves.

When it comes to measuring speed, the unanswered questions are how much these other forces affect forward motion:

A: If your rigid boat cuts through the waves, does the water crashing over the deck -- hitting into the paddler -- create enough resistance to affect speed? since the body of hte paddler offers a lot more surface area to these waves than the paddle blade offers to the water, does a breaking wave even have enough force to push the boat backwards?

B: If the rigid boat is bouyan enough to be carried over the crests of waves, is the forward speed going to be affected more by wave speed than by paddlong speed? Effectively you would be surfing a good part of the time is such a boat.

C: Is the flexibile boat actually traveling a longer distance by going around and over the outside of the waves? Does the flex make any design computations for rocker mmeaningless? (Rocker would be affected by weight distribution in the boat). With a somewhat flexible keel or backbone, is the power delivered by the paddler directed forward? Or up? Or down?

just a few thoughts.

PGJ