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Re: [FT] Hull strength and Stress

From: "Jared E Noble" <JNOBLE2@m...>
Date: Tue, 16 Mar 1999 10:27:01 -1000
Subject: Re: [FT] Hull strength and Stress

>Jared wrote:

>> ** Hull Stress Ratings **
>[Entire section snipped; I don't agree at all with the premises]
>The hull integrity doesn't have very much to do with withstanding
>acceleration stresses IMO. Even a Fragile-hulled ship is designed to
>survive its own engines without falling apart. (Count the necessary
>reinforcements into the Mass used for engines if you like!)

OK, It is _designed_ to withstand it's own engines. That's what I tried
to model
on the fly (the particulars for the design I submitted yesterday were
at the time - trying to flesh out the rough concept - see below)

>Instead, the hull integrity measures how much of the hull structure you
>can *remove* - how many bulkheads can be breached, how many struts torn
>off etc - before the ship no longer is able to survive the stresses
>caused by its own engines, etc. Indeed, some of the "engine damage"
>results may well be structural results instead - the hull takes such a
>bad hit that the captain doesn't dare to use his engines for fear that
>the ship be torn apart until the DCPs have assessed the damage.

2 points, so I'll respond separately

If integrity measures how much you can remove before before it can no
withstand its own engines, then is it an all-or-nothing affair. Why take
leap from full strength (can take th8) to destroyed (when the ship is
It seems a middle ground is reasonable (assuming it doesn't disrupt game
too much).

Engine hits as structural damage: Ok that is a potential abstraction to
it - but why? We havea damage track to show hull damage - we have
engines to
show damage to them.  Engines are already relatively small (at 5% per
rating) to
reflect hull damage as well.  Also if the captain "doesn't dare to use
engines for fear..." there are certainly times when it could become a
- high mission motivation type stuff...That dramiatic feel, you know.

>My solid mechanics professor did a rather fascinating demonstration of
>this in the first course I read for him. He is a rather big man - 90+
>kilos judging from his looks - and he put an empty soft drink can on
>its end and stepped on it. Stepped *up onto* it and stood there for
>almost a minute, because the can didn't buckle or get crushed. He then
>stepped down, made a very minor dent in the (cylindric) side of the
>can, put it back down and stepped on it again - and the can was
>immediately flattened. The small dent was enough to reduce the can's
>"hull integrity" to less than it needed to survive the stresses put on

great example, and actually to the point of the original idea I had-
'damaged' ships started to lose their integrity.  The idea of tying
strength to the hull strength came yesterday as I was typing my
mini-rant about
set 10% increments in hull integrity.  The 'integrity' concepts sounded
like a
potential link, so I went exploring the concept - hope you all didn't
mind the
brief trip.

>I imagine spaceships to work in a rather similar way. As long as the
>stresses *and the hull structure* are within the design parameters all
>is well, but when you remove enough of the hull structure that it drops
>outside the parameters... things tend to go pear-shaped.

Sure, I can buy that, but that still comes back to the basic idea of my
(and my original intent).  The first time I thought of the idea was for
FT2, and
basically what I considered was that for every threshold taken, reduce
safe acc by 2, starting at 8 for all ships, since that was the max any
could go.  What this meant is that big ships, with their typically
meager thrust
were never effected, but the smaller ships could be slowed down (unless
popped first - a common enough occurance.  So it pricipally would affect
cruisers - perhaps slowing them down for a couple of turns, and allowing
decision phase where the ship captain must weigh risks vs. potential
The attempt to model dramatic moments from various SF sources was also a
I admit.

Another quick note about what you said -
  "As long as the stresses *and the hull structure* are within the
   design parameters all is well"

Which is very well put. Since we have a system for modeling the source
of the
stresses (the drive) as well as one readily available for hull structure
(all it
needs is to have breakpoints determined) it seems that 90% of the
support is
there to consider them as 2 easily used pieces of the equation, rather
abstracting them into 1.

So I am more than happy to retract the concept of tying initial Stress
from the proposal, but would like your opinion -
Does the concept (not necessarily implementation) of reducing the
integrity' due to damage make sense? Is it any more or less logical than
a ship
which has lost 90% of it's hull points still thrusting around at th8? (I
that question sounds horribly biased, and that was not my intent - I
just can't
figure out how to word it to not reflect bias one way or the other.)
Is it illogical to assume that a ship, after taking damage, could have
it's hull
weakened to the point that full use of its own drives could actually
damage the hull?

>Oerjan Ohlson

Thanks for your comments!

Jared Noble
(who doesn't like to let an idea die if there is merit in the concept -
even if
my initial explanations or implementations consistently suck!)

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