> "The implementation of the pressure hose led to challenges in the dimensioning even for the small prototype, because conventional pressure hoses are usually d

> "The implementation of the pressure hose led to challenges in the dimensioning even for the small prototype, because conventional pressure hoses are usually designed for high internal pressures, but not for high external pressures. In addition, the installation becomes more demanding as the depth of the water increases. Greater water depths are associated with higher pressures, longer pressure hoses with greater friction losses and higher mechanical stresses. The more stable the hose wall is designed, the larger is its bending radius and weight, which in turn makes the installation more difficult." They tried it with a surface hose and without, and the full charge-dischage cycle were roughly equivalent, so the simpler version without the surface hose is the recommended option. https://www.sciencedirect.com/science/article/am/pii/S2352152X21007891 https://www.sciencedirect.com/science/article/am/pii/S235215... (PDF)