Vacuum test question

I tested my just completed 4" vessel to 15hg vacuum and it held a solid 15hg for 30 minutes. My quest is this: Will the vessel handle a depth of 130’ without leaking? Thanks for your help.

Hi Kenneth,

The vacuum test shows that the seals are in place properly and that there aren’t any obvious leaks. The 4" Series enclosure is designed for a rating of 100m depth and as long as the seals are in place it should be able to do that just fine. I’m confident it will work well and everything is set up properly.


what do you recommend for vacuum testing is there a chart anywhere



We usually recommend pulling a vacuum of about 10 inHg for 5-15 minutes. You’re looking for any major leaks that decrease the vacuum. Is there any particular information you’re looking for?


Hi All,

I have pulled a 22 in vacuum on one of the 4 inch diameter WTCs with 10 of the end cap cable penetrators filled with wires and over a 24 hour period only lost less than 0.5 in of vacuum.



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no rusty, that was the answer, I was pressure testing just by dropping the case into water as I put in the penetrations. its 80 feet off the back of my boat at the marina. thought using a vacuum might be easier and quicker just didn’t know how much vacuum to pull.



Hi John,

Great! Your depth test off the boat will definitely provide testing for greater depths but it takes a lot more time. The vacuum test provides a quick validation that all the seals are in good shape. You can pull to higher vacuum if you want to simulate greater depth, but you can only simulate about 10m maximum.


must be nice. i cant seem to keep test more than 5 mins. i had to splice every wire because the thruster wire is to short for my project.

@SaferHarbors if you need thrusters with longer cables I’d recommend you contact to see whether we can support a custom order that suits your requirements :slight_smile:

I don’t believe we offer completely custom lengths, but there should at least be a few different options - I think the longest is 3m, beyond which the voltage drop through the cable is generally too significant to be worth it. It’s generally easier to order a long cable and cut it to length than order a short cable and add an extension - especially where waterproofing is concerned.