In simplified terms the original HYPACC was a giant static air gun
that used water pressure to contain and compress air (air is not so good for the job as it is too heavy).
he new version HYPACC 2
, is more like a single stroke engine that rises from the seabed and accelerates toward the surface. At a point near the surface its top opens and uses water like a piston to pump hydrogen to a massive pressure (like an air gun).
he hydrogen is not mixed with oxygen so it does not burn. Hydrogen is the fastest, lightest gas and delivers the pumped up energy to the projectile with greatest efficiency. To help get the ‘engine’ moving as fast as possible the same idea as a ‘water-rocket’ is used beneath to accelerate the whole thing upward.
he key to making it work is to have an empty (rarefied) cylinder at the top for the water to rush into. This is done with a mixture of hydrogen and oxygen, which is ignited. Once burned it forms steam, which, in turn, condenses to water, leaving a vacuum cylinder for the water to fill.
n effect this sucks the whole thing upwards, helped along by the water-rocket below. The water rushing down the cylinder is about to have a head-on collision with the device that is shooting up. Hundreds of tonnes of water are crashing towards hundreds of tonnes of steel with a pocket of hydrogen gas standing between them.
he energy from that collision pumps the hydrogen to thousands of atmospheres, firing the projectile out of the barrel.