A tiny but rather powerful pair of mods. It wil inflate your MM cache just as its older brother, Rational Resources does. RHD brings long-awaited ease of design of undersea vessels by appropriately setting high or low buoyancy values to parts, and setting appropriately diverse pressure limit values so that some parts have more...or less ability to survive extreme pressures when you go to Difficulty Settings and enable Part Pressure Limits.

New Matters

...To watch out for.

• The first is that now anything can be expected to sink when you don't want it to. If you want to say afloat, then design with more lift surface and less wet mass, and be prepared to shed mass quickly. This especially includes the EVA kerbal. You will want to find or create a mod for equippable floatation or undersea propulsion devices. The kerbal can barely float now, and may sink immediately just by adding life support. And oceans with lower density than Water, such as LqdMethane, will be that much more easy to sink in.
• You may experience weird and incurable tipping over in some submersible designs. If this is the case then you have just met the need for a mod for a "Center of Buoyancy" marker.

Cheats

In case you find that the presets applied by RHD are weak, or you want to be able to stretch the restrictions, just edit the values of either of the two keys in Cheats.cfg.