These configuration files will create some new parts out of stock KSP models. They mostly use standard model meshes and textures. Due to changes made in the latest release I have had to bring over a few models from the older releases. There are no patches or new modules required for the main parts, and no outside dependencies. Most parts will be grouped together if you type water in to the search box up at the top left when building. RCS will cover the EMU command chair and EMU thruster block and the monopropellant intake.
There is a Module Manager Patch to give your Kerbals the ability to Buoyancy Compensate, so they can sink or balance to become neutrally buoyant.
It also adds an extra inventory slot. This was needed because of the new suits and changes to the way Kerbals interact with water and experiments.
The WUResources.cfg adds 6 new resources to the game that are required for the marine engines, intakes and ballast tanks/weights, and kerbal EVA Ballast to function.
The engines, intakes and thrusters are designed to be close to useless above water, but get more powerful as you dive down. Each size of engine impeller is designed to push an equivalent size submarine to over 130 m/s. Kerbal physics tends to get rough on craft going over 200 m/s underwater. When using canards as control surfaces horizontally it is best to set the authority limiters to 5 or under as water will cause direction changes to be far more sensitive than in air. Ballast tanks should be placed along the centre line in both up/down and left/right axis of cylyndrical subs, or ever so slightly down from there, otherwise you will find your nose trying to aim down, or in the direction you are offset. Ships on the otherhand will want them just above the keel. 2 ballast tanks, one at the front and one a the back will allow you to sink and balance flat and neutrally buoyant in most cases, engines tend to be more buoyant so usually the rear tank needs more weight. In very buoyant Rockomax size Subs you might need to put 2 full Baguette ballast tanks in the centre and turn off  their fuel flow in the UI. To balance in the water, pick 1 end tank and when you need to adjust front to back, click it's fuel flow to off and then use the trim functions to increase or decrease the ballast in the other tank to get level(you don't need to swap to the other tank to do this), put the fuel flow back on to fill or empty both tanks at once.
Most underwater RCS and all engine impellers will require water intakes to function, If you use the EVA thruster blocks on a micro sub you will require the Iron Steam generator intake.
The Marine command chair doesn't require an intake to use the Marine thruster block but eventually the battery will run out if not recharged by docking to a submarine.
The micro docking port allows you to dock and become part of the mothership but you can't transfer crew through it.
The EMU chair for working in space has a battery and monopropellant supply, they are limited amounts but the chair is quite frugal when using the EMU thruster blocks.
Both chairs have a Mechjeb core so will support it if you have that Mod pack. The ballast tanks have tweakscale supported. The new nacelles have their own inbuilt impellars to give more push to ships on the surface and for the 2 smallest have been balanced to barely float so that you have less hassle creating boats. The largest sits half way and will need extra mass to make it go under, This is because it takes around 26 ton to get it to sit underwater due to the way buoyancy is calculated. ENJOY.
