Part Buoyancy Values?

[LaytheDragon]

Recently, I have jumped into my 1.0.5 testing sandbox to test submarine designs to use in that sandbox or in the later game in my career save. I created two submarine designs over the weekend; a very small submarine that just fits into an Mk2 cargo bay (with part clipping into the bay walls, but with nothing poking through the outside), and a very large and elaborate submarine. As I was testing the large one, the SunkenSapphire Submarine, a cool exploration device that can also transport small submarines, I found out that despite the fact that about half it's mass is ore, it won't sink, and yet, the small submarine, for some odd reason, still sinks slowly with full fuel when all of it's ore is ejected. This got me to pondering, what are the buoyancy values for fuel tanks?  Is there a way to easily find out how many ore tanks are needed to sink a creation without actually going to the water?

Here is an album so you can see the submarines:

 

[Speeding Mullet]

I just found this post by @NathanKell which looks to be a highly accurate way of figuring out displacement.

This spreadsheet in the same thread by @Pds314 also has some very useful information on buoyancy to check out.

Hope that get's you started on your route to figuring this one out.

EDIT:  Wouldn't it be awesome if there was a buoyancy button in the SPH/VAB much like the COM COL etc to visually see how floaty or sinky your craft is.

SM

 

Edited December 15, 2015 by Speeding Mullet

[NathanKell]

Not just highly accurate but 100% accurate: that literally *is* the displacement formula I wrote.

[Speeding Mullet]

1 hour ago, NathanKell said:

Not just highly accurate but 100% accurate: that literally *is* the displacement formula I wrote.

Your displacement formulas float our boats!

Edited December 15, 2015 by Speeding Mullet
inserted marginally more witty reply.

[LaytheDragon]

17 hours ago, Speeding Mullet said:

 Wouldn't it be awesome if there was a buoyancy button in the SPH/VAB much like the COM COL etc to visually see how floaty or sinky your craft is.

That would be perfect, as it would be much easier than calculating parts with a formula manually or doing manual testing. Would it be possible for someone to make that a mod? That probably isn't something that will ever be in the stock game unless we get underwater biomes based on depth (a shallows, twilight, and midnight maybe), or unless Squad already has made one and is going to add it.

I am now going to attempt to fix my submarine based on the information given. Enjoy a like!

 

[Speeding Mullet]

13 minutes ago, LaytheDragon said:

That would be perfect, as it would be much easier than calculating parts with a formula manually or doing manual testing. Would it be possible for someone to make that a mod? That probably isn't something that will ever be in the stock game unless we get underwater biomes based on depth (a shallows, twilight, and midnight maybe), or unless Squad already has made one and is going to add it.

I am now going to attempt to fix my submarine based on the information given. Enjoy a like!

 

Thanks, I think it's worthy of a suggestion so I will make it so in the appropriate forum.

SM

[NathanKell]

You can fairly easily trawl all parts and calculate buoyancy, and give a net force. What's much harder is making that into something actually useful, because if you're building anything except a submarine you don't care about whether the whole darn boat/plane will float, but where the water line will be. It's not relevant if the seaplane floats...by putting its wings and engines in the water.

[Speeding Mullet]

10 minutes ago, NathanKell said:

What's much harder is making that into something actually useful

I see your point here It would indeed be challenging.  where as COM COL and COT are endlessly useful in designing a rocket or space-plane, a displacement indicator would have very limited applications, and perhaps a better suggestion would be a waterline indicator (thin line depicting the waterline maybe?). 

A displacement indicator would still make sense for limited applications such as submarines, underwater bases, and some specialised rovers, but yes, it's a limited requirement.

I suspect this point of view will crop up in the game development suggestion thread I just made about the same topic.

SM

[LaytheDragon]

4 hours ago, NathanKell said:

You can fairly easily trawl all parts and calculate buoyancy, and give a net force. What's much harder is making that into something actually useful, because if you're building anything except a submarine you don't care about whether the whole darn boat/plane will float, but where the water line will be. It's not relevant if the seaplane floats...by putting its wings and engines in the water.

I say it would make a good mod, one to give a Center of Buoyancy and/also (a mod to add) a waterline indicator, rather than add the Center of Buoyancy marker to the stock game. But I cannot mod, and I don't know if this is moddable or not (you should know, though). Center of Buoyancy could also potentially be made into a science part instead.

A waterline indicator would be very useful for making Laythe bases, to line up docking ports and such if the base is in the water, though land bases and bases partially on/in both are much more useful. (It'd be cool to have subs dock under a base, though a waterline indicator wouldn't be too useful for that. A water base could use the indicator to dock after shuttling ore from land to make the base useful)

In the meantime, I will have to use the information provided in this thread to fix my submarine, and I will probably wait until the weekend to do that, as I am busy with my career mode game during this week.