I am still not convinced that making a crew module (or pretty much anything) out of something that can be cut with a butter knife and that catches fire if you as much as spit on it is a good idea.

Mg, OTOH is well behaved - it needs a lot of heat dumped into it before it ignites, has good mechanical properties and you can even make jet engine parts out of it.

IMO potassium shouldn't even be available as structural material in game, only as possible coolant.

I've read that potasium, while painfully nasty, does react with the inner layer of the tank to form byproducts that potassium cannot react with. Dangerous, YES, but I am not confident that on a ship with a RTG that is about 50K away from melting. As far as criminals and nukes, in the COADE universe super enriched fuel seems to be pretty common and silicon areogel is cheap so...

The only feasible way to get the crew into potassium CM on a ship using fluorine oxidizer would be to restrain them and build the ship around (taking into account that they would be kicking and screaming all the time).

Criminals are unliely to nuke you, but a bunch of bolted-on missile or drone grade chemical motors would let them dodge the missiles with relative ease.

Magnesium is nasty if it catches fire, but it's pretty inert in bulk and due to being light and strong is attractive enough to be used as structural material in automotive and aviation - both civilian and miltary.

Potassium OTOH is downright nasty all the time - soft, melty, reacts with pretty much everything and catches fire for no good reason. Definitely not a CM (or anything else structural) material.

Selenium doesn't seem to be used as structural material at all and solar abundance is low, so I don't know why it is so cheap, nor if it's actually attractive mechanically (which I didn't expect since it's essentially a more metallic cousin of sulfur).

The micromissles are for disabling civllian ships/lightly armed criminal ships when the cutter does not want to get close, this is a police ship, so the missles and guns are not here to punch through 5 CM of boron fillament.

Magnesium tends to burn when in contact with oxygen (I think), thats why im not using it on crew modules, selenium is only stongish, but it is cheap.

Wait, is selenium actually this strong or are we dealing with boron 2.0?

What's wrong with, say, magnesium? I'd probably prefer using something else for CM specifically, but it's nice, light, abundant and sane engineering material. I'm not that fond of selenium because it's actually quite puzzling whyy it's so cheap in CoADE - it's actually quite a rare element and properties are nothing to write home about.

Anyway, you have definitely hit home when it comes to cheap and light - no argument here - and the ship is definitely a keeper.

I still think that rapid fire guns would serve it better than micromissiles (the RG is sweet, though; also I wonder how well would those micromissiles perform if fired out of high velocity gun or blast launcher) and that it might be possible to improve upon this design with changes to mass distribution (effectively free turnabout boost), roll capability and some sort of thin anti-flash layer (silica aerogel?), possibly shaving the very rim of boron filament cap to make up for the extra mass and cost.

Just my two cents.

As far as making cheap ships, crew modules made of selenium if you want to play fair and potassium if you don't are real life savers.

Thanks Atom Heart Dragon, this really wasn't designed to be a competitive warship, just a how small can I get things test ship. It is made for the space equivilant of the coastguard so they can have something with a little bit of punch to it instead of ships with no weapons, will be making changes.

For the record:
A more expensive ship might be more cost effective overall and vastly more mass effective:
While I can't seem to be able to match low cost and mass (I just cannot into cheap ships), I can build around 1.5x heavier 8x more expensive ship that can most of the time win against fleet of cutters matching its cost.

Of course, if you need many ships in many different places, on budget, you could put a cutter around every rock in the belt.

Impressive mass and cost minimization.
A few points, if you don't mind:
- Fluorine tank so far in the rear massively increses moment of inertia and contributes to awful turnabout (you could massively increase agility just by swapping the tanks around).
- Lack of roll capability means that most of the time destroying only one railgun shuts the ship down if it tries to stay nose forward.
- Nice low-power railgun (I like limited power designs in general). I'm not a fan of graphogel barrel armor, but since we can't have barrel fins...
- It could use some nuke flash protection, paper-thin aluminium foil is none.
- Missiles are a bit crap - low delta-v and can actually be outrun, impressively tiny though.
- Could use some high RoF weapon to complement slow firing rails.
- I'm not a fan of Co-60 (scary stuff), but that's a nice, sane radshield (PE, not Li-6)
- OTOH potassium CM doesn't seem like remotely sane engineering even when it isn't next to a fluorine tank.