New Weapons!

Plasma gun (deals aprox. 100 hp damage+ 10 hp radiaton dmg, lasts 3 seconds, 12 secs to reload, 20 range)
Plasma blaster (deals 150 dmg, 15 radiaton dmg for 3 secs, 15 seconds to reload, 18 range)
Plasma launcher [mortar version] 200 hp dmg 20 rad dmg 3sec, moderate range, 15 sec reload)
Tagger [explosive launcher] stick a bomb on the enemy or environment, explodes when detonate button [new UI button] pressed, dealing 200 dmg, 5 shots/clip, 15 sec to reload.

 

Your plasma weapons sound a lot like flare gun and fire bombs. The issue with that is you would create even more issues of players fireing fire bomb, plasma launcher and dealing massive damage over time to create these spam wepons since they would be on different training trees.

I like your idea of the tagged as you could tag a unfriendly and wait for them to get closer to another ship for AOE damage. It is different and creative.

One wepon that would be interesting to add would be a sidewinder missle. Think of it as an above water big torpedo but it rotates in the air so it would be harder to determine where it would land. It would be a little faster than big torpedo, have an arc, and would do similar damage

 

I like the c4 idea and the sidewinder missle

 

Flamethrower! Burning everything in a cone in front of you in a descent range

 

I'm for a flamethrower! But it should set fire to water like napalm, only in real time and a small affected area, the point is that if you shoot, the water burns, as you stop shooting, the water immediately stops burning. A range of flamethrower navreno less than the carronade.

 

I like the Tagger!

I find the Plasmas to be unfitting for the setting. A little too high tech. Im not overly fond of the Railgun existing either, for the same reason.

The setting is obviously a catalyst unknown, Oceanic Apocalypse which caused the water levels to reclaim much of the land. The area we play in appears to be the UK, though it may be completely made up and just resemble it.

Also, radiation generally only interferes with Electromagnetics, and Organic Matter, not Ships. While Radiation damage is a neat idea, and could be said to be damaging the “crew” aspect of the HP of a ship, i feel that it’s inaccurately represented in your example.