Crotch strap Importance with a double hose

[Paladin]

I had an experience in September that I feel I should share, especially with those who are new to diving double hose regulators.

I was diving at Twin Quarries with my oldest son and a friend of mine. I was using my twin 72s and my PRAM. Everything was going well until I swam head down toward a boat on the bottom. When I got to the bottom, I suddenly found it very difficult to get enough air. No matter how deeply I breathed, it wasn't enough. I finally decided to head for the surface and then try to figure out what was wrong.

At the surface, I inflated my horse collar BC and relaxed until I had caught my breath. At one point, I tilted my head and the back of my head hit the flat side of the regulator can. I knew then what had happened. When I went head down, my twin tanks had shifted and placed my PRAM at a position too far from the level of my lungs.

I repositioned the backpack and harness and continued the dive normally, taking care to not let the tanks shift again.

The reason for the shift was the absence of a crotch strap on the backpack. I had dived a double hose reg many years ago using the same style of backpack but only with single steel 72s. My first rig, at age 11, was an old-fashioned military harness that I swapped for my first backpack in the late '60s. The waist belt of that back pack was sufficient to keep a single in place without a crotch strap and I dived that (back pack/72/DAAM) rig for several years with no problem. When I started diving a double hose again last year, I never thought about the missing crotch strap until the incident in September. The weight of twins, evidently, made the difference.

I now have a BP/W setup for my twins, with a crotch strap, of course. I also have installed a crotch strap on the back pack I use for diving singles with my PRAM, just in case.

So, any of you who are new to double hose diving, remember to install a crotch strap to whatever rig you're diving and make sure it's snug enough to keep your tank(s), and regulator, in the proper position.

 

[DaleC]

Good write up Paladin,
I won't deny the importance of positioning the cans correctly but I have had mixed results with the crotch strap issue. I can't help noticing that there are many examples of early diving rigs that don't use them and, like the sternum strap, wonder if it was a regional thing. They also rarely used them on Sea Hunt but I don't know if that was more to do with filming constraints(?).

I installed one on my rig but find that my weight belt interferes with the positioning of the tanks. On my frame a ST72 has to sit low over my butt for proper can positioning but the weightbelt over the crotchstrap won't allow the tank to sit that low.
I can dive without a crotch strap and just occasionally have to reach back and pull the tank down or... I can put the crotch strap over the weightbelt (which has its own issues of trapping the weightbelt).

I keep tinkering with the postion of the bands on the tank etc... to try to find a compromise but haven't found it yet.

 

[Luis H]

I always attach the front of my crotch strap to my weight belt (not to my back pack waist belt). The crotch strap has a loop with a fastec (sp?) buckle and it is the last thing that I attach. In this fashion I can drop my weight belt and the front of crotch strap just falls with it. The weight belt is not trapped.


Note: As far as I know, this is the same way the Calypso divers wore their crotch strap, when they wore a weight belt.



BTW: as far as I can remember, Mike Nelson (and everyone in Sea Hunt) always wore a crotch strap. I don’t remember seeing a sternum strap, but I will look he next time I am watching Sea Hunt.

 

[simonbeans]

Put the two bands as indicated on this photo. Unless you are 3' tall, you have plenty of room to slide the weight belt under the tank and over the harness. Posiition the weights so that you have about 6 " or so of open belt at the back, directly beneath the tank.

 

[Paladin]

Dale C,
I no longer use a weight belt. I now have velcro weight pockets that I slide directly onto the harness' waist strap. This turns both my BP/W and my single tank back pack into weight integrated units while retaining the ability to dump weights if needed. This eliminates any problems caused by a separate weight belt.

Luis,
Mike Nelson used both a crotch strap and a sternum strap. Simonbeans kindly made me a sternum strap that cured a harness slippage problem I was having when we dived together at Portage last summer.

Thanks again, Allan!

 

[DaleC]

I stand corrected on the Sea Hunt issue. I just checked a number of episodes and see the crotch straps now (Duh...). When Mikes not wearing his white wetsuit they tend to blur with his trunks. I notice though, that he often is trapping his weightbelt under the waistbelt... interesting.
Luis, do you thread the loop of your crotch strap through the weight belt or is there one half of the fastex buckle on each strap/belt?
Thanks Simon for that image. It's a good guide.

 

[elmer fudd]

It doesn't seem to make a lot of difference to me. Perhaps that's due to having a few extra pounds of belly that prevents the waist belt from riding up.

 

[Paladin]

It doesn't seem to make a lot of difference to me. Perhaps that's due to having a few extra pounds of belly that prevents the waist belt from riding up.

Lucky you. I don't have a defined waist. My torso is pretty much the same diameter from thighs to armpits. I really need something to keep my waist strap in place. So, ye olde crotch strap!

 

[Luis H]

I stand corrected on the Sea Hunt issue. I just checked a number of episodes and see the crotch straps now (Duh...). When Mikes not wearing his white wetsuit they tend to blur with his trunks. I notice though, that he often is trapping his weightbelt under the waistbelt... interesting.
Luis, do you thread the loop of your crotch strap through the weight belt or is there one half of the fastex buckle on each strap/belt?
Thanks Simon for that image. It's a good guide.

I make a loop with the crotch strap around any weight belt I may be using (I don't always use the same weight belt).

I do have one (vintage style) back pack with a crotch strap that has a semi-fixed loop. In this case I just open the weight belt at the last minute and thread the loop on the front over the weight belt.

I try to always keep the loop on the free end of the weight belt (not the buckle end). This helps the weight belt fall free, but with a big loop it will fall in either case. After a dive, I often drop my weight belt before I remove my tank and it always falls to the ground.

 

[duckbill]

It seems like one could fasten a hook to the end of the crotch strap. Then you could run the strap up behind the weight belt and hook over the top of it. That way the weight belt could fall free and the crotch strap is not attached to it at all, and it would work with any weight belt.