Does water temperature affect fin performance?

absolutely roy,water temp affects everything!!!the water temp ruined my last marriage,and that's all I have to say about that

 

It's not blatantly noticeable, I already bulk up my boards (volume, width, thickness, etc.) for winter to compensate for a wet wetsuit weighing up to 30 lbs. But I don't know man, I'm all for experimenting with his fin suggestions though- especially with the cold weather moving in quickly in the northeast.

 

Water temperature (cold) has a negative affect of performance...of my nutssssss

 

I'm no scientist but I do know that the water get denser as it gets colder. Possibly more drag? Interesting observation Roy.

 

as a physicist, my opinion is:

wattre in winntre ~=30 min.
summre ~=80 max. correct?

thats 50F fluctuation. enough to require diff whacks on your stick. but fins? lets explore further

some of the more popular compounds used in manufacturing of surfboard fins are:

G10 :

Physical Properties Metric English
Density 1.80 g/cc 0.0650 lb/in³
Water Absorption 0.10 % 0.10 %

Mechanical Properties Metric English
Hardness, Rockwell M 110 110
Tensile Strength at Break 262 MPa 38000 psi
310 MPa 45000 psi
Flexural Strength 448 MPa 65000 psi
517 MPa 75000 psi
Flexural Modulus 16.5 GPa 2400 ksi
18.6 GPa 2700 ksi
Compressive Strength 448 MPa 65000 psi
Izod Impact, Notched 6.41 J/cm 12.0 ft-lb/in
7.47 J/cm 14.0 ft-lb/in
Thermal Properties Metric English
CTE, linear 9.90 µm/m-°C 5.50 µin/in-°F
@Temperature 20.0 °C @Temperature 68.0 °F
CTE, linear, Transverse to Flow 11.9 µm/m-°C 6.61 µin/in-°F
@Temperature 20.0 °C @Temperature 68.0 °F
Thermal Conductivity 0.288 W/m-K 2.00 BTU-in/hr-ft²-°F
Maximum Service Temperature, Air 140 °C 284 °F

Fiberglass:

Physical Properties Metric English
Specific Gravity 2.49 g/cc 2.49 g/cc

Mechanical Properties Metric English
Hardness, Mohs 6.5 6.5
Tensile Strength, Ultimate 3033 MPa 439900 psi
Elongation at Yield 4.8 % 4.8 % 100% Elastic Recovery
Modulus of Elasticity 69.0 GPa 10000 ksi

Thermal Properties Metric English
CTE, linear 7.20 µm/m-°C 4.00 µin/in-°F
@Temperature 100 °C @Temperature 212 °F
Specific Heat Capacity 0.887 J/g-°C 0.212 BTU/lb-°F
Softening Point 749 °C 1380 °F

in other words.... if it doesn't soften - it doesn't affect flex, if it doesn't affect flex, it doesn't affect water redirection. aka i doubt you'll notice a difference.

my .02

 

This is cool.

 

least of my worries. What, are you thinking of developing some sort of fin heating/cooling system?...no more bong-hits for you

 

heres a free one for all ya'll: spring loaded fins. angle of attack (rotational pop) or, leading/trailing edge (speed control via surface area variation....think aircraft wing flaps.. the more water pushes it in - the more it retracts = speed control. you need less of a wing at higher speeds.
. _________
>=======
something like that with lateral springs inside the fin body.

 

You just sent the gnome off in a frantic lather, T.

 

What are the thoughts on water displacement on flat surfaces i.e. Dimples on surfboard hulls and fins?

 

been done...giant failure.

 

no dude, thats longitudinal angle variation. I'm talking lateral rotation and/or surface area variation.

besides, you gotta hide those springs, salt water and sand and all... getting warmer tho... not affecting flex yet tho.

 

ok, yeah...that's impossible.

 

:b

 

10 people. I joint. 2 hits each?

 

Like I said, I'm no scientist.

 

This reminds me... wait..