Getting my trim 100% sorted for Twins

[John Touhig]

OK, I’ve been diving twins for a year now (and what an interesting year it’s been, but that’s another story) and I’ve never been 100% happy with my trim in the water. It seems I’m always fighting to keep my legs up and horizontal. If I relax then my legs start to drop. This can make deco hard work.

Kit is as follows:

Twin Faber lightweight 12lts, MDE Manifold.
Stainless Steel Backplate rigged with a one piece harness.
CD TBD wing
Membrane Drysuit
Quattro fins

I’ve tried moving the cylinders up a hole on the wing but that turned out to be way too drastic as I spent the whole dive inverted.

Shutdowns can only be achieved with my left hand grabbing the bottom of my cylinders and shoving them up so I can reach the valves.

Does anyone have any tips or hints how I can improve the situation.


Thanks

John

[MATTBIN]

Do you wear a weightbelt or similar, or is all the weight in the kit i.e. b/p etc.

Matt

[John Touhig]

Originally Posted by MATTBIN

Do you wear a weightbelt or similar, or is all the weight in the kit i.e. b/p etc.

Matt

In the salty stuff I wear 7kg around my waist in a shot belt.

[MATTBIN]

I use my weight belt to get my trim right on my inverted 10's, even though I dont actually need the weight (in fresh) without it I would have very floaty feet, yours seems to be the opposite, as you cant get the tanks up higher I am suspicious the weight belt is causing the heavy feet problem. The tanks may be down a bit too far so slide them up in the bands rather than a whole bolthole. I would try that gradual movement of the tanks, which may also help with shutdowns, if its still not enough I'd move some of my weight from the weightbelt to a better location further up somehow so it trimmed me better.

HTH
Matt

[Little Pete]

As Matt said, sounds like the belt is pulling your waist/legs down. Have you considered shifting some of the weight up in the form of a V-weight on your cylinders?

[Janos]

Originally Posted by Little Pete

As Matt said, sounds like the belt is pulling your waist/legs down. Have you considered shifting some of the weight up in the form of a V-weight on your cylinders?

I think it's the weightbelt too. I used to have this problem, when I dived with a Transpac, which has no metal in it. I used to either camband a couple of kilos of lead high up the tanks, or use (homemade) weight pockets on a camband (which I still have and use when on holiday).

I would definitely try digging out a spare camband and strapping on a couple kilos and see if it makes a difference.

I wanted a more permanent solution and in the end this was the prompt for me to get a 5mm Woz plate which shifted around 5kg of weight from my belt to between my shoulderblades. This fixed it for me. If you've already got a plate then as suggested up there ^^^ you can use v-weights which is a more permanent solution.

Go to your local quarry and have a play.

Janos

[Clare Gledhill]

Getting the bands right on your cylinders helps.

Wearing a weighbelt doesn't help.

But most of all it is getting used to what flat feels like and where your calves need to be (how extended) to trim you out.

[nigelH]

Originally Posted by John Touhig

I’ve tried moving the cylinders up a hole on the wing but that turned out to be way too drastic as I spent the whole dive inverted.

I slid the cylinders up the bands until I balanced.
Trimmed for a nice frog-kick I do feel a bit light about the feet but it's never inverted me since I got it right.
When I switched to the YBOD I replicated the same balance and it still works.

[Mark Powell]

Try bending your knees a bit more to start with, this will move your centre of gravity up and will also trap a bit of air in your feet.

If you still are not trimmed then move some of the weight from your weight belt. Of course first make sure that you really do need all of that weight in the first place. A heavier backplate or v-weight will help move the weight up.

Moving the cylinders up in the bands will also move the weight and will help you to reach the valves as long as you don't move them up too much in which case it becomes counter productive.

Try each these one at a time so that you can check progress and don't end up going too far the other way.

I have to go to Wraysbury sometime next week to test a new wing so if you want to come along I can can give you some feedback.

[garygee]

Hi John

Its not a easy task, I know you change one things and get that right then you find you cant do somthing else.

I went through a similar time with shutdowns and part of cracking that ws to get my buoyancy spot on, so I could just float flat with no monement/finning while doing shut downs.

Have a look at http://www.yorkshire-divers.co.uk/fo...t=24151&page=3 this is how I get their may be of help but I found its wanst one big thing but a combination of many.

Stick with it and as people have said do one change at once.

Regards Gary