something is not right here..
vertical lift is created at expense of ..?
another force that could propel vehicle forward
so need to check if final is somehow beneficial at all
result will be again combination of everything again.

no it's not a free lunch but this is what michiel was referring to with regards context.

although the upward force is reducing the amount of sideways lift it is also allowing the board to plane earlier which then decreases hull drag so you go faster so the fin then creates more lift etc. it's a point of balancing the forces. you accelerate until the system reaches equalibrium. usually drag/aoa based. or you lose control and one force becomes dominant. staying in equalibrium is the most efficient

in the context of the system it is important to remember that the sail is not only applying a force sideways, it is applying a force forwards, downwards and backwards. the fin is also applying a force vertically, backwards, sideways and i gues forwards if you consider the nose of the board lifting. the board is applying a force upwards, forewards, sideways and backwards.

you can trim any of those forces purely by your stance. (except drag to a larger extent)

then there is buoyant force

Macroscien said...

Gestalt said...

i know this fin theory stuff is based more around speed sailing etc, but thought i'd also mention,

in racing terms an increased lift of 6-7kg or i guess a weight reduction, in lighter winds would be of great benefit.

if not that easy, nothing like free lunch
that lifting force was create by expense ... lower lift etc
could be but as you look at hydrofoil fin experiment - such windsurfer is not faster at all ..forces to lift windsurfing board could be bigger that resistance of planning board

Macroscien said...

Actually that is already proven technology to inject air bubbles underneath commercial ships to lower water resistance and save on fuel 10 to 15 %
. The same could be beneficial to sailboard....
I feel quite comfortable trailing white wash left by motorboat , but not sure yet if going any faster ...

Don't expect that the prop backwash will slow you down when you get within a few meters. You might end up in the boat with the fisherman as the board seems to leap forward

Regarding the flexi fin, I think that the fastest racer will maintain ZERO vertical lift.
He will store and release energy from the waves and thus maintain a constant speed. No accelleration or decelleration of the board means no lost energy, except from the sailor, but that is what he went to the gym for..

That was done at the 1985 slalom worlds in Lake Garda by a Greek guy on the F2 team. I think he'd modified a Sunset.

The idea was old then - Craig Hughes did it with the 1977 Vee Jay dinghy champ Nu Hissy if I recall correctly (I was only a kid but I have the article somewhere).

It's one of the many things that people rediscover every few years.

ffs call simon anderson will ya?

now that is cool

it's basic shape looks very contemporary (ignoring the length).