You learn something every day


Do you see the garbage can with the red X through it on this McMurdo hydrostatic release? After many years of selling and installing these units I finally did. What is means is pretty obvious, you can’t throw this device in the trash, but I had to ask the question of why.

The other hydrostatic release on the market (the Hammar unit) is purely a mechanical device. Water pressure pushes against a diaphragm causing it to move and release a spring loaded knife. There is nothing hazardous with this unit. McMurdo went a different route and apparently uses a very small pyrotechnic charge in their device. This charge is small enough that they can ship these without having to declare them as hazardous material. It is large enough that they must be disposed of as a pyrotechnic device, just like your flares.

I have asked for more information from McMurdo but so far the phone stays silent. Checking the documentation that comes with a new hydrostatic release and there is no mention of proper disposal. Going further I checked the owners manual for the EPIRB’s these are used in, again no mention of HRU disposal.

I will update this post if/when I have more information. Until then please dispose of these properly, the same way you do your flares.