Hi All!

First post, and generally unfamiliar with the community and rc submarines. I have a project for university, requiring us to design a system which can descend and ascend, to as deep as possible preferably (but not critical). It is encouraged to use off the shelf components, rather than design everything from scratch. I have done research and found applications of using a syringe, RCABS, peristaltic pumps to simulate a buoyancy engine. However, I have having difficulty finding a fully commercial one available, only a model from Arkmodels.
Note it doesn't have to be super complex - it is only going up and down so no complex ballast system is needed! It just should be reliable and ideally have a failsafe mechanism. Can anyone help me point me in the right direction of a commercially available buoyancy engine, or possibly at least one that would require minimal parts to supply?

Thanks