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post #458 of Old 08-08-2013
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Re: Pros and cons of steel sailboats

Originally Posted by mark2gmtrans View Post

I know you are severely challenged on the math because you just cannot in good conscious be saying that I could exert three million pounds of force on one of your thin skinned little boats and not squish it flat, much less thinking that I could give your hull a three million pound impact and not send the thing to the moon with a GIANT GAPING HOLE IN IT.

Exert a three million PSI impact on the keel and it would probably exit the hull through the deck and land somewhere on Mars.

But, I am happy if you are happy, so if you have people buying your BS boats then go forth be fruitful and multiply.
You are talking about two things here. Million pound forces and impact forces. These are quite different things the way I see it. You are also mixing PSI and forces.

Brent specifically mentions pounding forces from waves, so it might be interesting to determine what these pounding forces might be.

My boat, 20000 lbs, say 10000 kg, drops off a 10 foot wave into a trough. Due to dynamic forces decelerates in about a foot or so. Acceleration of gravity is 9.8 m/s^2. Deceleration is about 100 m/s^2 when it hit the bottom of the wave. So total force is.. you do the math.. 1,000,000 N or 200,000 pounds.

Now I am sure Catalina has significant design margins.. could be a factor of 5. So it seems, it is not very hard to get to 1,000,000 pounds of force.

However, again I must point out that Brents number of millions of pounds is not incorrect. But your interpretation of it seems to be incorrect.

Last edited by BryceGTX; 08-08-2013 at 02:07 AM.
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