4" tube custom length cut question

Hi guys,

I was going to order a custom length of the 4" between 16" and 20". can you tell me how much that will limit my max depth? It would be helpful to know the estimated max depth for 16" and 20". I don’t need a guarantee, a close ballpark would be fine. Thanks!

Hi Brandon,

We use Under Pressure to calculate the failure depth of these tubes. The standard 12" long tube has a unsupported length of about 10" and a calculated failure depth of 192 meters. You obviously want to derate for safety, which is why our official rating is 100m.

I just did the calcs for 16" and 20" and here’s the results:

12" (10" unsupported): 192m failure depth
16" (14" unsupported): 145m failure depth
20" (18" unsupported): 131m failure depth

Remember to leave some safety factor! Hope that helps!


You guys have the best customer support of any product I have ever dealt with. Thank you for turning me on to the calculator and running the numbers for me, above and beyond. Thanks.

Brandon, happy to help and thanks for the kind words!