Trying to pass oil through BlueRobotics bulkhead


I am currently working on an autonomous undersea glider using BlueRobotic parts. I have designed a ballast system to increase and decrease the density of the glider for its propulsion system. I am currently struggling to find a part that will allow me to pass oil from an external bladder to an internal bladder through one of the 4" bulkheads. I have a simple penetrator from Blue Trail engineering but it only has a barb on one side. I have also attempted to use multiple barb to barb penetrators I found online however, none of them have O-ring seats and therefore cannot form a good seal against the bulkhead. I am considering trying to pot a tube through one of the bulkhead penetrators but I am concerned that the tubing may squish and cause a leak. The project is intended to be open source once completed so any solution needs to be reasonably priced and I would like to avoid having something custom machined.

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I did something similar to make a pass-thru for a 6mm polyamide tubing…

You can just use a Wetlink M10 6.5HC pénétrator and re-drill the penetrator to 6mm ! ( it’s ok because 8.5 penetrators are drilled to 6.5mm )

Of course, you can also use a metal tubing if you need higher pressures.

What depth do you bring that too? Ideally, I would like no less than 150meters. Do you think it would survive that? Unfortunately, I cannot use all metal tubing due to some other connections inside the glider, however, having metal for the wetlink to seal on I think would be a good idea, do you know of any good barb or high pressure push to connect fittings that could be attached to a 6mm stainless steel tube?

Due to my pump choice, i’m limited to less than 100m.
Anyway, if you look at semi-rigid polyamide tubing properties, it looks like there’s no problem for your targeted depth !


This is great thank you! Can I ask what you’re using for a pump, or could I see the plumbing setup you have? I’m currently using an RC hydraulic pump (Hydraulic Pump - Xtreem RC), it seems to work so far but I am very skeptical that it can actually reach 8Mpa.

Sorry, i’ve not the hand on this ROV at this time !

I use a TCS micropump :
not the same price …