Problems with trim, feet sinking

[dkktsunami]

Weight pockets on cam bands - XS Scuba.

 

[1_T_Submariner]

Most last recreational safety stops are practiced at 3-5m 15-20ft, this is were you should be able to maintain neutral bouyancy.

Yes Safety stop 15-20 feet Thanks for pointing that out I didn't intend that the safety stop was 3-5 feet. You should still be in control of Bouanancy at all times. I'm not a big fan of Safety stop is over lets pop to the surface! A controlled ascent the entire time is a Good practice IMHO. Just my 500psi.

 

[ScubaWulf]

I'm not having any buoyancy issues, I can park at my safety stop and hover there with no problems at all. My issue is with trim, and my center of gravity in the water allowing easy positioning horizontal or vertical rather than always tipping vertical.

Sorry, probably got too wordy there. I use a Zeagle Express Tech. It has two tank bands. I placed the weight pouches on the upper band. The weight distribution keeps me trim without finning. I've also seen weight pouches that go on your shoulder straps. Wrap a weight belt around the tank yoke and see if weight up high helps trim you out.

 

[randytay]

I'm likely going the route of BP/W, but it seems a considerably more complex purchase than just buying a BC off the shelf - I see several package options of course but the complexity is due to the flexibility of the modular system.

Not really. You actually only need 4 components: a stainless steel backplate; a 1 piece continuous webbing with crotch strap and the d-rings, a wing with about 30lbs lift (single tank) and a STA with cam bands and you're all set. Everything else in a "package" is superfluous.

 

[TSandM]

You state that you did not have trim problems on a prior trip, with a weight-integrated BC (but I assume a different one) and ask why that might be.

My first question would be, did you change anything else in your gear, especially your fins? Fins make a huge difference, because they are out there at the end of a long lever arm.

My second question would be whether the two BCs hit you at different places on your torso. If the weight integration is, as it usually is, at the bottom of the BC when you are standing up, and the BC is longer, the weight will be further down and therefore tend to pull your feet down.

The final question would be regarding the type of tank -- were you using the same kind on both trips? Both the total buoyancy and the top-to-bottom balance is different between different kinds of tanks.

Don't be put off by the complexity of a backplate system, because the flip side of the complexity is the flexibility. With a BC, you can't move weight pockets or trim pockets around, and you often can't put weight pockets on the camband or cambands, because of the way they are mounted. A backplate will permit all of those things, and if trim is important to you, I really think a modular system is the way to go.

 

[Peter Guy]

A couple of years ago I went diving off Molokini in by Balance/integrated weights, jet fins/spring straps -- found I was having a very hard time keeping horizontal. I finally looked at the wall I was drifting by and asked myself, "Why do I care? I'm drifting along a wall taking pictures -- what difference does it make what position I'm in?"

I had a very pleasant dive, most of it at a 70 degree angle! My Fundies instructor would have been amused.

 

[MauiScubaSteve]

Just finished a great dive vacation in Maui but had problems maintaining trim on most of my dives. When I mounted the tank very high on the BCD I was fine but this was occasionally a bit awkward when I looked forward and my head was resting on the valve. I ended up having to do a lot of little finning to keep my trim - I'm sure this affected my air consumption.

How could I have resolved this? I asked the LDS we rented our gear from but they had zero suggestions (probably just the uninspired dude working the counter that day). The only thing I could come up with was putting a weight at the top of my tank. I was using an AquaLung weight integrated BC. I didn't have this problem at all in a prior dive trip also using weight integrated. I'm 6', 185lbs, so pretty normal body size. I'm looking at making a BC purchase soon and if there are things I should be considering to help this I want to be aware of them. Any suggestions would be helpful.

Ok, in your profile you "label" yourself as a "Vacation Diver" but your pic seems to have been taken during your Dry Suit Specialty dives. And the only exposure protection listed is a full 3 mm.

You don't list fins or booties but you are "looking at making a BC purchase soon."

There are many brass tacks to step on here. A really good first Q is; are you going to dive locally? If so, then a BP/W should be considered.

Have you been paying attention to the gear you have been renting? What model AL BC did you use on your Maui dives? What model BC(s) have you used in the past. What fins did you use on your Maui dives? What fins have you used in the past? Preferably paired to BC used. Were you using the same wet suit previously? Did you wear the "Beanie" in Maui waters?

Trim pockets are now standard equipment for many Vest BC's, but body positioning is how many divers do it. Aftermarket trim pockets that attach to tank straps are also popular; before those were available ankle weight on tank neck works really well but some first stages don't like that config. Let's go back to body position.

If one dives with a slightly head lower than waist body alignment, and a slight arch to the back, the bubble of air in the Vest BC is mostly in the lumbar area. A weight belt is typically positioned directly below that bubble. Well thought out integrated weights should be along this same vertical axis.

The downward rotational force of your legs/feet is not noticed when finning, due to thrust and hydrodynamics. When you slow to a halt, bending the knees, bringing fins up, lessens the downward rotational force.

Some divers have bird bones and their legs float. Some Vest and BI BC's are better for those body types because they are possibly designed to help "lower" floaty legs. There are also better Vest and BI BC's for those with sinker legs.

Or instead of learning to control your body position, you could just get a BP/W that controls your body position for you.