Comparing subs

[sebu]

Hello swarmbrain of SB! I'd like to ask you something...
I know my designs have been crambed during... well; always. However; I'd like to know what I'm doing wrong?
As an example, there are a great drawing of a fellow citizen lambda compared with my AU sub. So; what am I doing wrong with this and why? The size difference is obvious...

[heuhen]

Depends on what you are asking about! But notice how much space the enginering space take up on Borei-3, all the way from aft of the missile compartement, everything is for the powerplant.

Now your's are battery powered I pressume, that change some things

[sebu]

Thanks heuhen! Yes; the engineering space in the nuclear sub is my worry/guestion. I admit I've just used reactor from AceL-factory without further knowledge...
I'm not a nuclear/ship/rocket-engineer; just a designer
So, I increased the reactor area a bit. Russians need height of 7,5m for this and mine is about 5m. On the other hand, they can blow up their subs because of bad engineering; so how much it matters...? I also added cut-markings.

[heuhen]

If you was to go nuclear, your engineringn space needs to be at least twice the size. The reactor from Ace. is more of an surface ship reactor without or minium shielding. And I don't think it have the necesary power. The size of the engine compartment is more similar to and conventional submarine. And the mini subs doesn't help with the internal space

If you look at the Borei-3, the point 28 on that drawing is the reactor in it self. Their reactors are quite fine, their problems is that they do not invest enough in maintenance on their subs, altough they use more mony on maintenance and new equipment for their submarine force and navy than anything else.

Their reactors is also a normal pressure vessel reactors, just like what UK and US are using.

Remember a nuclear powerplant is an big steam engines, just in submarine they have done it as compact as possible. Go and look and steam trains, they use similar principals as an nuclear powerplant, except they burn coal or oil or gas to produce steam, while a nuclear powerplant use an nuclear reacotor to boil water, but they have to do it trough an heat exchanger then directly, you don't want to boil water inside and nucelar vessel.

[acelanceloet]

There are a few things you have to keep in mind.

- The weight of a submarine is the displacement of it's pressure hulls, all other spaces are either void space or ballast tanks when submerged (well technically you can subtract the volume of the metal outside of the pressure hull from that but that is, especially for sb purposes, negligible)
- The size of the ballast tanks is the volume of the pressure hulls that is above the waterline when on the surface. All those ballast tanks have to be below the waterline, so all non-pressure hull spaces above the waterline are void spaces and filled with water when submerged and filled with air when above the water
- The center of bouyancy when submerged ( which is the volume centroid of the pressure hulls) is directly above the center of gravity of the entire submarine.

What does this all mean? it means that if you have something heavy, like machinery, very far aft, you also need bouyancy very far aft. Which is troubling, since there isn't much need for anything aft of the machinery. This is why reactors, diesel engines etc are kept as close to amidships as possible: the crew spaces that are forwards are relatively light in comparison.
To make sure the submarine stays level, any variable loads (fuel, torpedo's, missiles, food, waste, even the crew walking around) have to be compensated with trim tanks. As you cannot have empty tanks outside the pressure hulls, these ballast tanks are inside the pressure hulls.

In your design, that means you have to compensate for torpedo's, the missiles, the submarine hangar and the submarine in it, stores......

In addition, you need very large ballast tanks, I suspect, although I am not sure how much of the sub comes above the waterline.

Lastly, you need to put a lot of heavy stuff forwards (non-variable, so ballast tanks do not count) to compensate for the weight of the electric motors and the LWNP aft.

If you work on the above things, you'll see a much more comparable layout and relative sizes of spaces compared to other subs, I suspect

[sebu]

Thanks for reply, lads. Yeah, it seems weight management isn't my cup of tea... I should do much more corrections than just delete minisub-hangar. But I got the answer i was looking for so thanks again heuhen and ace. I quess I'll bury this and delete those images. Time to do something else...