Sidemount Tanks with Top Mounted Stages interfering with frog kick

[markmantei]

I have 50-75 sidemount dives under my belt. Most of those dives have been either with no stages or a single top mounted AL40, tanks are typically Faber HP120's (my preference), although sometimes I'll use Worthington HP130's. I don't recall ever having an issue before, but last time I dove SM was the beginning of December. I have an upcoming trip, and will need to carry an AL80 of 50% and an AL40 of O2 in addition to the 120's. As I hadn't dove with an AL80 before I figured I would jump in the pool fully geared except for the drysuit. Anyways with the stages on (top mounted) it feels like the 120's are interfering with my frog kick and I am needing to "push" the 120's out of the way with my quads each kick cycle. I am pretty sure the tanks are well trimmed (like I said, no issues before). I could sling the tanks instead (I keep a standard stage strap in addition to the bungees for top mounting), but in general I feel there is already too much going on with reg hoses, light cords, and inflator hoses, and prefer the cleaner top mounting of the stages. It's possible that the extra weight from the stages was affecting my trim in the water with just a wetsuit on (I definitely felt foot heavy), which is an issue that should resolve itself by adding the drysuit. Am I the only one with this issue? Any suggestions?

 

[sock]

Hello
Never have had any issues with top mounting stages. The only thing is after you have used your third (speaking about overhead environment) you should consider moving them to below your primary bottles to avoid damaging the environment and to maintain proper trim. In regards to being foot heavy, try readjusting the position of attachment points on the primary bottles.
best of luck

 

[Dive-aholic]

Your kick is too wide. You should be using just your ankles and calves for frog kicking, not your hips and thighs. Also, on the subject of top mounting decompression bottles, what are you doing to confirm your mix when you switch to it? Can you actually see the markings on your bottles? Or are you unclipping your decompression bottles to look at them then clipping them back after confirming?

 

[JamesK]

I am really new to staging with sidemount, so take what I have to say with a grain of salt. While I have somewhere around 200 sidemount dives, less then 5% of that involves stages. However, I do carry deco bottles, AL40's quite a bit. I find bottom mounting the deco bottles to work much nicer then top clipping. Plus I can see my bottle easier for gas verification.

For too mounting stages I am playing with Rob's idea of bungee leashes to keep them down. I still look very foolish trying to clip and unclip a stage.

 

[markmantei]

Just about to start the last day of the trip, so I though I would update the thread. I did not notice the issue at all, so I would say my pool dive was a red herring. Don't know if it was kick stance like Rob suggested or some rigging that wasn't quite adjusted properly in the pool for the thinner exposure suit, but just glad that it wasn't an issue. Rob to address the issue of confirming tanks, I am able to pull on the tank valve and turn my head to see markings I place on the tank shoulder. I'm using the nomad ring system so everything pulls fairly easily and confirming mixes is not difficult. Thanks for the suggestions!

 

[beanojones]

Your kick is too wide. You should be using just your ankles and calves for frog kicking, not your hips and thighs.

What's the reasoning behind this?

 

[Karl_H]

Just to check is it when using stages on the top that you’re having problems or are you top mounting deco tanks?

I’d still suggest deco tanks should be mounted on the bottom rather than on-top, this keeps with the same logic as most of us use in back-mount that the richest gas is on the bottom while also means the easiest valves/regs to access at the primary gas you are using. If you’re using Al80s the steel 120s should also help out with trimming out the deco tanks if they are not full. Just make sure you use deco tanks with an upper clip which is mounted very tightly to the tank neck and a shorter tail on the lower clip (or loop the tail through the handle above the tank band to shorten it) and they should trim well.

I’d have to strongly disagree with not using your hips on a frog kick, in fact the main difference between a modified frog kick and a normal frog kick is the hips/thighs? There’s three joints that can be used in the frog kick, the ankles, the knees and the hips, the latter having much more power. A modified frog kick tends to be done with just the ankles and knees (i.e. most power from the calves), as long as you avoid spreading your ass and keeping your knees close together you can get a good amount of power out of this kick, although in strong current/flow or just on a long distance OW swim it’s better to use the hips.

In fact this is one of the biggest problems we see with tech/SM students, most find it easier to adopt a legs open position – this normally causes the knees to drop (so your trim tends to suffer), but the main factor is that it removes the ability to use the hips in a strong frog kick – similarly it stops the fin blades slapping (or almost slapping) together which means you lose most of the power available in a modified frog kick.

Karl

 

[Dive-aholic]

What's the reasoning behind this?

Two reasons. First, using the hips means you are using larger muscles. Larger muscles require more oxygen when used so you increase your RMV. My RMV is .35-.4 because I don't use my hips. Second, when you use the hips you spread your legs out farther. This creates drag in the water and slows your movement down. Using just your calves and ankles minimizes drag and allows you to cover more distance. Just using my calves and ankles I can swim at a pace of about 65 fpm and against strong flow. With the right fins, swimming with just the calves and ankles can be quite powerful.


James, what size clip are you using on the bottom bungee?

 

[JamesK]

Rob, it is an extra large bolt snap from DGE.

 

[Dive-aholic]

Okay, that's the same one I'm using. The weight of the bolt snap should assist it dropping below your sidemount tank. Then place your left thumb inside the eye of the bolt snap and pull it across to your d-ring. If you have too much trouble with it then the d-ring is positioned too laterally. Just move it more midline and try it then. Another thing that helps is to clip the bottom first, then the top.