Scaleing

Here is a link with aome more opinions.
http://home.clara.net/gmatkin/therules.htm

 

I was thinking about immersed volume....volume of model ^3 x 1 or 1.026 according to liquid spec. weight. Sorry to have explained badly my thinking!.

 

okay, this may sound stupid, but is everything scalable, even the power-plant? Honestly I always thought that the density of water screwed up scale. So lets say I wanted to scale speed, how do you do that? is it really like my boat is doing 300mph? as example with that same hull there's people pushing it 40mph, where its starts chine walking and sometimes even barrel rolls. that would be 480mph.

 

For the power:
Power real = Power model x scale^3.5

For speed :
Speed real = Speed model x scale^0.5

For torque :
Torque real = torque model x scale^4

For revolutions :
Revolutions real = revolutions model x scale^-0.5

 

Raggi the specific weight of the fresh water, taken as stansard value for 24° t is 1000 kg/m^3.....To be sure I've looked in Internet.....

 

INternet and internet..
http://www.engineeringtoolbox.com/water-density-specific-weight-d_595.html
Temperature Density
0 999.9
5 1000
10 999.7
20 998.2
30 995.7

 

For a boat having a volume of 10'000 kg :

In fresh water the displacement for me will be 10'000 kg and for you 9'970 kg........i.e. -0.3% !

 

Don't get mad
If the boat weighs 10 tons (metric), I would say it displaces approx 10.030 cubic meters in fresh water at 25 degrees. At 4 to 5 degress the freswater has a density of 1000kg/m3. That's what I learnt at college.

 

Which College ?

Sorry but 10 m^3 in fresh water corresponds to 10 t for me!

Visiting your College I will certanly change my opinion....if it is an opinion.

 

Have a look at this graph. Units in the x-axis are ºC.
Cheers.

 

We are discussing about 0.3 % .....white flag!

 

But that change in density is one of the fantastic marvels of the natural world. If density continued to increase at a constant rate with decreasing temperature, lakes and ponds would freeze all the way down to the bottom and all the fish would die.

But as water is at its most dense at 4 degrees it sinks to the lowest level and you get a temperature inversion with water cooler than 4 degrees rising to the surface.

 

Crag, you are a poet!

 

Crag, I remember a 1000 times when I was a kid, and went skiing across lakes, that my father always mentioned that his college (!) teacher used to say that it was one of nature's wonders that water has it max density at 4 degrees and not 0
Ranchi, it may have been high school!
What do call the school after 9 years, the three years before university?
Anyway, did the nice graphics from Guillermo change your mind?

 

Raggi try to undestand me....I've always assumed a value 1 because the difference btw. 997 and 1000 are 0.3%.....nuts!

The same question for PHI = 3.14...... you can stop when you want.....until the infinity...but good practice is for me to stop it after 7 decimals i.e. 3.1415926...then is enough.

Fresh water density is the same thing for me why 997 and not 9968546.......

I round at 1 and for me is enough!