Hydraulics

[Farley]

Does anyone have a spreadsheet or can offer assistance on hydraulics. I know very little about hydraulics apart from the simple theory. I need to size every component required for a hydraulic system for raising and lowering a stern ramp.

thanks for any help

[TeddyDiver]

Something to start with..
http://www.hydraproducts.co.uk/Hydraulic-Calculator.htm

[daiquiri]

Thanks for a great and useful link, TD.

But the hydraulic calculations are the second phase of the design. The mechanical analysis of the stern ramp's motion has to be performed first, in order to establish the acceleratons, forces involved and power required to produce the desired relationship between stern ramp's position and/or angular speed and time.

[gonzo]

That's exactly what I think too. Until you design whatever it is that the hydraulics will operate, it is not possible to specify the requirements.

[jehardiman]

Originally Posted by daiquiri

Thanks for a great and useful link, TD.

But the hydraulic calculations are the second phase of the design. The mechanical analysis of the stern ramp's motion has to be performed first, in order to establish the acceleratons, forces involved and power required to produce the desired relationship between stern ramp's position and/or angular speed and time.

Originally Posted by gonzo

That's exactly what I think too. Until you design whatever it is that the hydraulics will operate, it is not possible to specify the requirements.

Daiquiri and Gonzo are right here, you need to work up the structural and hydro loads first. Having helped design many large hydraulicly operated items to work at sea, the first step in the hydraulic design is to figure what the hydrodynamic loads are going to be to determine wether the mechanical design is up to the loads and if you are giving the loads a mechanical advantage on the hydraulics. I have seen what happens when 15,000+ psi is back-driven into the hydraulic system by hydro loads on an item..... much to the detriment of the piping....then they asked me to figure out the wave slap loading. Damn lucky nobody died.