Mailing List Archive

Mailing List: techdiver

Message Display

  dlv@ga*.ne* (Dan Volker) wrote (Subject: Force Fin Challenge):-
> ... the mis-information that [Force Fins] are a "good" fin for everyone.
> What I want to demonstrate is that they are only good for people who either
> like to swim slow (i.e., macro photographers) or have to swim slow (the
> physically unfit who cramp easily or have heart conditions, etc.) ... how
> "efficient" Force Fins are ...

By `efficient' of fins (or boat propellers etc) at each speed, do you mean
like this?:-
  X = total energy that the diver's legs expend while swimming
  A = energy used by the thighs and shins making eddies and pushing water
sideways as they go up and down
  X-A = energy that reaches the fins
  B = energy used by the fins making eddies and pushing water sideways as they
go up and down
  D = energy that ends up as backward-moving water, i.e. the diver equivalent
of propeller wash or jet backblast
  S = X-A-B-C-D = energy that does get used in pushing the diver forwards
  Minus propulsion caused by other parts of the legs than the fins. Likely in
fin swimming that amount is small, but I get the impression that in breast
stroke swimming a fair amount of propulsion is caused by water pushed out
from between the thighs.
  Has any proper hydrodynamic research been done on this? if so, does anyone
out there know any relevant scientific paper references?
  (Plus as a side issue how much energy gets wasted pushing badly-shaped kit
through the water making e.g. tail eddies behind a thick square-ended
cylinder.)

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]