Is heavier better when it comes to boats?

[burgundyben]

Re: Chris_d, me and the Nobel Prize

Quite right Antony.

The Greek bloke had it.

If you are more dense (physically) than water then you will sink and displace water equal to your volume minus the tiny bit of compression of your body caused by the pressure of the water (ah ha, another complicating factor!!).

If any item is less dense than water, ie less than 1 kg per litre volume, then it will float, the amount above the water is an expression of the ratio between density of water and the floating item.

Man in the bath is like boat that has been run aground, it is displacing some water, the difference between what its displacing whilst aground and not aground will be equal to the pressure it is exerting on what ever it has run aground on.

On the subject of my displacement, lets just say that its less than BIGMART and more than TCM. The amount is not important, these things are relative, I am relatively less heavy than my brother who is my relative, see?




<hr width=100% size=1>Sod the Healey - I think I'll buy an E-Type.

 

[adarcy]

Re: Chris_d, me and the Nobel Prize

Dang

Do you really think I won't get a half of a Nobel prize then, I was hoping you might change sides.

Yes let's keep our displacements/density out of it

<hr width=100% size=1>

 

[oldgit]

Re: O yes it does VS O no it does not

/forums/images/icons/laugh.gif

<hr width=100% size=1>If it aint broke fix it till it is.

 

[alpha]

Re: O yes it does VS O no it does not

Going back to the first post here, which states:

'OK, so if you've got an aeroplane, lighter is better, right?'

I can't help recalling all the hours I spent filling competition gliders with water ballast in order to make them heavier, which made them go faster and handle better.

No, mass or displacement is only part of the equation. You need to go and have a pint with your nearest tame bellybutton designer (Naval Architect) and ask him about speed, stability (in the various axes), sea-keeping, handling,
and so forth.

At the end of it, buy the boat that's right!

<hr width=100% size=1>

 

[Jerbro]

Re: O yes it does VS O no it does not

'I can't help recalling all the hours I spent filling competition gliders with water ballast in order to make them heavier, which made them go faster and handle better.'

Presumably you weren't trying to increase the overall weight of the glider, but just get the c of g right?


<hr width=100% size=1>Jerbro
====
Click here for <A target="_blank" HREF=http://www.btinternet.com/~jerbro> My ex-boat pics</A>

 

[alpha]

Re: O yes it does VS O no it does not

No, as I said, the objective is to get the mass up.

As this is a boating forum, not a gliding one, I'll be very brief: a heavier aircraft requires more lift to stay airborne, and this is achieved by flying faster, as Bernoulli states that L=1/2.rho.v(squared).s.cL where L is lift, rho is density, v is speed, s is surface area of the aerofoil, and cL is the coefficient of Lift at the given angle of attack (don't worry too much about this bit). The glide angle stays the same, but the forward speed is greater, so you win the race!

<hr width=100% size=1>