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I think we can simplify AAs equation into; :-)Smilies ++++++++++ Bucks. Personally the price of fins has got ridiculous. And as one poster has pointed out; manouevrability is a problem. So is spelling... Fins can be produced for different purposes. A good diver will explore various options *for the task he has in mind*. The problems are threefold i) too many 'bad' divers being turned out ii) too many 'bad' salesmen and iii) bad advice to beginners; I personally don't advise FFs due to the fact that I can't teach them how to get the most out of them, which is as good a reason as any. Let them hoist their own petard if they must. Jason > 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.) > -- > Send mail for the `techdiver' mailing list to `techdiver@terra.net'. > Send subscription/archive requests to `techdiver-request@terra.net'.
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