trim adjustment with BP/Wings

[merkin]

Hi, everyone, I'm looking for some help getting the trim correct in my new setup.

I'm diving freshwater in a 5/4mm steamer with a Al80, 27# Pioneer wing, 6# SS BP and 8#s soft lead in the weight belt (centered in back 2 of 6 pockets). I might be able to take another 1# off the weight belt as yesterday I sank VERY slowly at 15' with 500psi and normal breath (I have big lungs!) on my last dive.

Problem - I'm having trouble maintaing a horizontal position when diving. My legs tend to sink so that I'm diving heads-up, maybe at 30-40 degree angle. My buddy yesterday said it was only a slight angle, but I keep feeling like if I closed my eyes and did nothing, my present equilibrium would be standing! Also, feels like I might be arching my back during the dive to compensate.

I've noticed this before with some rental gear setups so I'm thinking it may be anatomical?

I can think of 3 potential things, but would like some help recognizing the proper solution, or other suggestions?

1) weight on my hips - should I buy one of the 6-8# STA's to get as much weight as possible higher up?

2) I tried positioning the AL80 6" higher on the second dive - it helped a bit, but not enough. It would become awkward if I moved it much higher.

3) I tried swimming with legs bent at a 90 degree angle (for frog kick etc...), but this didn't seem to help much - I'm not very good at this so it could also have been poor technique.

MISC question - in salt water with a 3mm steamer - how should my weight change? What about with a 1mm steamer or nothing? [this affects what size STA I buy if that's the best solution]

Thanks for any help!

 

[detroit diver]

merkin once bubbled...
Hi, everyone, I'm looking for some help getting the trim correct in my new setup.

I'm diving freshwater in a 5/4mm steamer with a Al80, 27# Pioneer wing, 6# SS BP and 8#s soft lead in the weight belt (centered in back 2 of 6 pockets). I might be able to take another 1# off the weight belt as yesterday I sank VERY slowly at 15' with 500psi and normal breath (I have big lungs!) on my last dive.

Problem - I'm having trouble maintaing a horizontal position when diving. My legs tend to sink so that I'm diving heads-up, maybe at 30-40 degree angle. My buddy yesterday said it was only a slight angle, but I keep feeling like if I closed my eyes and did nothing, my present equilibrium would be standing! Also, feels like I might be arching my back during the dive to compensate.

I've noticed this before with some rental gear setups so I'm thinking it may be anatomical?

I can think of 3 potential things, but would like some help recognizing the proper solution, or other suggestions?

1) weight on my hips - should I buy one of the 6-8# STA's to get as much weight as possible higher up?

2) I tried positioning the AL80 6" higher on the second dive - it helped a bit, but not enough. It would become awkward if I moved it much higher.

3) I tried swimming with legs bent at a 90 degree angle (for frog kick etc...), but this didn't seem to help much - I'm not very good at this so it could also have been poor technique.

MISC question - in salt water with a 3mm steamer - how should my weight change? What about with a 1mm steamer or nothing? [this affects what size STA I buy if that's the best solution]

Thanks for any help!

A couple of things come to mind.

1. You're SUPPOSED to arch your back! That's one of the things you'll learn in the DIRF class. If you're not sore for the first few dives, you're doing it wrong. Take a DIRF class.

2. Your backplate may be too low. Proper positioning is important.

3. Your tank may be too low. Ever see how low most people wear their tanks with a poodle jacket? How can they reach their valves (yeh, like they ever try)?

4. Leg angle adjustment will affect your trim. Take a DIRF class.

5. A couple of pounds on an STA higher up will help, and removing some weight from the belt. What "pockets" are you speaking of when talking about weight placement?

 

[leadweight]

Try threading a 2 or 3 pound weight on the center of your top camband, this may help. Bending the knees a bit may help level you out some. Move those soft weights back towards the side or front of your body. Try this on a beach dive with an easy entry/exit so that you can get in and out of the water to mess with this stuff without wearing yourself out.

My experience with changing weights for different thickness of wetsuits is that 1 mil of neoprene removed equals about 2 pounds of lead removed, for an average size person. This is a starter, your mileage may vary.

 

[merkin]

Thanks for the responses. I'm planning on taking a DIRf class in April, but would like to be close on my trim before I get there, plus, it's kind of pain to dive when I keep ending up near vertical. My back doesn't hurt afterwards, but I am arching. The soft weight is on a conventional belt (with 6 pockets), not any of the GUE packs, etc...

1) How do you move the BP up and still have the straps comfortable?

I tried the BAUE website advice, but went about ~2-3" lower with the BP for strap comfort (the plate ends up flush against my back)... with the present postion I can still reach and turn the valve on my tank ON/OFF and reach the top of the plate with my hands (barely).

2) I'm always putting the tank in different places and recognize the need for consistency - what is the rule for positioning the AL80 (with a Pioneer 27lb, if more specifics needed)?

3) I'll try it next time I'm in a nearby spring, but why would moving weight to the front of the weightbelt help? What I am learning by doing this?

4) thanks for the weight adjustment on the wetsuit - I displace more than average (76" 210lbs) so I'll try 2.5# per 1 mm. Is best estimate - salt water +3lb?

 

[MikeS]

Merkin,

As an easy experiment, you may want to try putting ankle weight around the tank valve and removing an equal amount of weight from you weight belt. While this is not a good permanent solution it is a quick and inexpensive (especially if you borrow the ankle weights) way to see if shifting weight toward your head does in fact help.

Mike

 

[merkin]

I'm still interested in hearing answers to those other questions, but has anybody ever tried this before (is this what leadweight was suggesting)? I was thinking I could put 2x 2# lbs on the BP this way without buying anything. Doesn't seem too uncomfortable out of the water. May reduce the volume of the BP pocket a bit...

 

[crazyc]

Turn your BP around for starters. In the pic you posted, it looks as if you have the BP backwards. The center ridge should be the furthest from your spine, the wingnuts should nestle down inside.

 

[leadweight]

you managed to get a weight to fit into the channel of the BP. Not bad. If the cam band is long enough you could add another weight on either side of the tank.

Moving weights to the front was mentioned at a bouyancy clinic that is given at Coco View every week. If you are moving more weight to your back, this will offset any tippy feeling.

 

[WreckWriter]

crazyc once bubbled...
Turn your BP around for starters. In the pic you posted, it looks as if you have the BP backwards. The center ridge should be the furthest from your spine, the wingnuts should nestle down inside.

Crazyc is correct, the BP is backwards in the pic.

WW

 

[merkin]

Sorry, the resolution of the picture was reduced to make it easier to download.

However, I think it IS oriented as crazyc describes...in it's current setup, from my spine the next thing would be the wing nut and then the center ridge. The sides of the BP are closest to my back not the center ridge. Isn't that what you are prescribing?

Should I try putting another 2# on the lower tank strap in the same manner? Not sure, but figured I will first try testing the current revision in the water with 3# on both front lateral hips as leadweight suggests.

Can anyone give me a range or rule for where the Al80 should be positioned in relation to the Pioneer MC?

Thanks for the responses.