Can't get trimmed out.

[thethumper]

Ok.... I ditched the hose protectors. Put the infator hose between my head & the hose.

I dove Orange Grove this afternoon. I am diving twin 3300psi Catalina 80's. 35# -5.8 full, "0" (neutral) empty. I started out w/3900psi on a 300 bar DR man. w/iso. I dive a Goldcore 3mm 1 piece & the Goldcore 5mm "shorty" farmer john. I have an Al DR BP & Classic wing. I wore NO weight & SANK LIKE A CINDER BLOCK. Not to mention the best part, I was Soooooo head heavy I couldn't get horizontal. I was totally head donw/feet up. I put a weight belt on w/2 4# weights & that seemed to help a little, but the air I had to but in the wing.... Ughhh. The bands are as high on the tank as I can get them..... What to do???????????:confused:

These photos haven't been updated to the hose gaurdless yet.

http://www.thumpershole.com/equiptment_setup.htm

[Hallmac]

What to do???????????

I looked at your pictures and if the wings are still sitting at the level shown in the picture I think I can see the problem. It appears your wings are still too low on the tanks.

Does your bp have another set of holes? Do you have room to drill new ones?

If not or this would position the tanks too low for your build, consider this trick.

Using thin nylon string tie loops around the lower parts of the wings to limit how much air can collect there. try to force the air into the upper third of the wing. Do not use bungies and do not tie them completly off. make sure the knots hide behind the tanks to prevent them from catching on anything. Do this only as a last resort.

Hallmac

[crazyc]

thethumper once bubbled...
Ok.... I ditched the hose protectors. Put the infator hose between my head & the hose.

I dove Orange Grove this afternoon. I am diving twin 3300psi Catalina 80's. 35# -5.8 full, "0" (neutral) empty. I started out w/3900psi on a 300 bar DR man. w/iso. I dive a Goldcore 3mm 1 piece & the Goldcore 5mm "shorty" farmer john. I have an Al DR BP & Classic wing. I wore NO weight & SANK LIKE A CINDER BLOCK. Not to mention the best part, I was Soooooo head heavy I couldn't get horizontal. I was totally head donw/feet up. I put a weight belt on w/2 4# weights & that seemed to help a little, but the air I had to but in the wing.... Ughhh. The bands are as high on the tank as I can get them..... What to do???????????:confused:

These photos haven't been updated to the hose gaurdless yet.

http://www.thumpershole.com/equiptment_setup.htm

Okay, so if I get this correct, you had your tanks bumped up to 3900 psi, which gained you about an additional 20 cuft and added about 1.6 pounds to the overall total. An aluminum BP and no weight sent you head first heavy as all get out. So you added 8 pounds to a weight belt and that seemed to help somewhat to get you horizontal. So your COG is way far forward and you need to find a way to move it back a bit to help you balance out your system.

I had a similar experience trying to balance a heavy system and for some odd reason that dive I had grabbed my Mares Quattros instead of my jet fins. Actually I was doing it intentionally to prove to myself one way or another if my Jet fins really made a difference in my balance. With the Quattros if I tried to relax in a horizontal position, the system would pull me over head first. Once I put the Jet fins on, it was just enough to help me trim out again.

Also depending on what system I am diving, I will use V-weight in between the tanks and BP to adjust. I use a yellow Zeagle weight pouch and will put anywhere from 2 to 5 pounds (soft weight) in it, before placing the wing and BP on the tanks I will hook the loop over the tank band post (either top or bottom depending on which way I need to shift my COG) and then attach the wing and BP which holds the weight in place no matter what my position is in the water and also keeps it from shifting. But this allows me to adjust my trim and establish a better COG.

One last trick I found that has made a difference too, is to loosen up the crotch strap. This allows me to reposition whatever system I am wearing while U/W and get it into it's own comfort zone.

Please let me know what if anything you find helps you out.

Out of curiousity, have you drained your tanks to 500 psi and checked to see how much weight you would need at the end of your dive?

[wetman]

I had a bit of the same problem with my doubles rig as well - the further down you can get the weight, the less extra weight you'll need. I found a 2-pound weight in each thigh pocket did the trick. Maybe even a 1 pound ankle weight would get you trim (but you'd be shunned of course ;) )

steve

[Epinephelus]

There really is a place in the world for ankle weights - yours may well fit the bill. After you've done everythig you can to move the tanks lower, and you're still head-heavy and negative, ankle weights provide the most foot down trim for the least additional weight you can get.
E. itajara

[thethumper]

I was actually wearing 2 3#ers. As for the Bp. It's a Al DiveRite w/1 set of bolt holes. If I drill a 2nd set of holes to move the plate up (to move the tanks down my back) the plate will be too far up/too close to my regs. What I was thinking was to get a 6-8# weight w/the eyelet in both ends & "quick-link" it to the bottom 2 holes of my BP, so it spans from side to side @ the hip level. I'll still sink like the Titanic, but @ least I may be able to get trimmed out.

I use US Diver Blades. I tried a lrg. DR fin, but I needed a med. Maybe the jets would help w/trim?

[roturner]

thethumper once bubbled...
Ok.... I ditched the hose protectors. Put the infator hose between my head & the hose.

I dove Orange Grove this afternoon. I am diving twin 3300psi Catalina 80's. 35# -5.8 full, "0" (neutral) empty. I started out w/3900psi on a 300 bar DR man. w/iso. I dive a Goldcore 3mm 1 piece & the Goldcore 5mm "shorty" farmer john. I have an Al DR BP & Classic wing. I wore NO weight & SANK LIKE A CINDER BLOCK. Not to mention the best part, I was Soooooo head heavy I couldn't get horizontal. I was totally head donw/feet up. I put a weight belt on w/2 4# weights & that seemed to help a little, but the air I had to but in the wing.... Ughhh. The bands are as high on the tank as I can get them..... What to do???????????:confused:

These photos haven't been updated to the hose gaurdless yet.

http://www.thumpershole.com/equiptment_setup.htm

You might try loosening the shoulder straps a bit and wearing the whole rig a little lower down on your back. Even a couple of inches can make a difference. Do you have a keel weight?

R..

[thethumper]

roturner once bubbled...


You might try loosening the shoulder straps a bit and wearing the whole rig a little lower down on your back. Even a couple of inches can make a difference. Do you have a keel weight?

R..

If you're referring to a weight that attatches to or in between thetanks, I do not.

Maybe the boot on the tanks are too boyant.;)

[lucid]

<nt>

[kcanty]

First of all I wouldn't recommend overfilling aluminum tanks.
I do it all the time with steels but I'm cautious with aluminum
but it's your choice.

Also I have read that catalina's have undesireable bouyancy
characteristics compared to luxfers. I don't have any trouble
with my double luxfer 80's.

Which hole(s) of the DR classic are you using? All recent ones
have 2 sets of 3 holes for placing the wing on the BP. Using
the bottom hole of the 3 could help.

Are your fins neutral, positive or negative in the water?
Jet fins are definately negative especially with spring
heel straps. They may help if you don't have negative
fins.

You don't really have boots on your tanks, do you?

Kell

[Scubaroo]

kcanty once bubbled...
You don't really have boots on your tanks, do you?

Kell You can buy circular weights to go inside of a tank boot, but I think they're 5lb apiece - maybe you could cut one in half and add half to each tank boot.

Double tanks (or any tank) generally shouldn't be left standing unattended, so there's probably no real reason to leave the boots on.

[thethumper]

kcanty once bubbled...
First of all I wouldn't recommend overfilling aluminum tanks.
I do it all the time with steels but I'm cautious with aluminum
but it's your choice.

Also I have read that catalina's have undesireable bouyancy
characteristics compared to luxfers. I don't have any trouble
with my double luxfer 80's.

Which hole(s) of the DR classic are you using? All recent ones
have 2 sets of 3 holes for placing the wing on the BP. Using
the bottom hole of the 3 could help.

Are your fins neutral, positive or negative in the water?
Jet fins are definately negative especially with spring
heel straps. They may help if you don't have negative
fins.

You don't really have boots on your tanks, do you?


Kell

The Catalina's are 3300psi Catalina 80's. 35# -5.8 full, "0" (neutral) empty.

Using the bottom hole on the wing was to be my next thing to try. Get my boyancey to the top & further away from my butt. It's boyant enough. :D

My Blades are deffinantly negative. I have spring kit on them as well.

And... no... I don't REALLY need the boots, but if the bottoms take a hit.... it'll be the boot & not the tank.

Thanks.

[pescador775]

Clearly, you have too much weight between the shoulder blades. This is a common problem with DIR rigs. You'll notice the number of novel engineering approaches to your problem. That's because it takes an engineer to set up one of these rigs in the first place but mostly ends up trial and error. I suggest you stand by until 'genesis' sees this thread. He says that he is able to use these kits with decent trim parameter. I'm not sure if he's savy on fresh water though. In the meantime, 'lucid' has an interesting suggestion. Also, playing with fins and ankles is a non starter, wait for serious advice. You may have to trade in the heavy aluminum tanks or keep for salt water use only.

[WreckWriter]

Do any of your buddies own a set of Luxfer doubles? If so, try to do a dive with those tanks and no other changes. I'm betting the Cats have odd buoyancy characteristics as I've heard their 40 cf tanks do.

I have a set of "Super 80s", short tanks with close to neutral buoyancy empty that dive this same way, forcing a head down position. I've been unable to fix it easily so I don't use them much. On a shorter person they might work well.

One option you might try is to get a V-weight and cut it in half, just use the "bottom" part of it.

Tom

[Scubaroo]

pescador775 once bubbled...
Clearly, you have too much weight between the shoulder blades. This is a common problem with DIR rigs. You'll notice the number of novel engineering approaches to your problem. That's because it takes an engineer to set up one of these rigs in the first place but mostly ends up trial and error.I'm sorry pescador775, but that is one of the dumbest statements I've ever seen posted on ScubaBoard.

David didn't say anything about his rig being or attempting to be DIR, and backplates, wings and doubles have been around a lot longer than DIR. You're the first one to mention it in this thread. It's a simple trim problem, and instead you use it to take a cheap shot.

[thethumper]

WreckWriter once bubbled...
Do any of your buddies own a set of Luxfer doubles? If so, try to do a dive with those tanks and no other changes. I'm betting the Cats have odd buoyancy characteristics as I've heard their 40 cf tanks do.

I have a set of "Super 80s", short tanks with close to neutral buoyancy empty that dive this same way, forcing a head down position. I've been unable to fix it easily so I don't use them much. On a shorter person they might work well.

One option you might try is to get a V-weight and cut it in half, just use the "bottom" part of it.

Tom

Actually my buddy who bought the same BP/Wing/manifold I bought & dove w/yesterday dove Luxfor & was fine. Hhhmmm.

[Scubaroo]

I believe O-ring has a set of Catalinas doubled up - try shooting him a PM. He might be on vacation at the moment though.

[thethumper]

Scubaroo once bubbled...
I believe O-ring has a set of Catalinas doubled up - try shooting him a PM. He might be on vacation at the moment though.

He's always on vacation. But I'l PM any how

[pescador775]

David didn't say anything about his rig being or attempting to be DIR, and backplates, wings and doubles have been around a lot longer than DIR. You're the first one to mention it in this thread. It's a simple trim problem, and instead you use it to take a cheap shot.

Don't be sorry, be right. True, the ATPAC was around back in the mid 70's, initially got a lot of attention from Skin Diver, then died. Later, back yard experimenters started tinkering with the design but it didn't take off until DIR hype gave the thing a boost. It's an improvement, for some people.

[Wreck/Tec]

I have an OMS System. The DIR school discourages elastometric bands on the wings. They view them as an entanglement hazzard. I tried to dive my twin 98s all summer with out the bands. I to was severely face heavy. I added the bands to my 100 lb wing and problem solved. There was too much air towards the rear, and air shift was to radical. DIR has many good points. In my opinion, that wasn't one of them! Hope it helps.......
Wreck/Tec

[thethumper]

Wreck/Tec once bubbled...
I have an OMS System. The DIR school discourages elastometric bands on the wings. They view them as an entanglement hazzard. I tried to dive my twin 98s all summer with out the bands. I to was severely face heavy. I added the bands to my 100 lb wing and problem solved. There was too much air towards the rear, and air shift was to radical. DIR has many good points. In my opinion, that wasn't one of them! Hope it helps.......
Wreck/Tec

Perhaps I should pull my Classic off & put my Rec wing on it. TOOOOO many options.

[nradov]

Those Catalina C80 tanks are a little too negatively buoyant to work well as doubles with a wetsuit. And most of that negative buoyancy is near the top of the tank which will tend to push your head down. Try swapping them for a pair of Luxfer S080 tanks, which are positively buoyant when empty, and make up the difference with a weight belt. This will also allow you to have more ditchable weight in case the wing fails (balanced rig).

Also, if you can move the tank bands up a little that will help to shift the weight toward your feet.

-Nick

[MikeFerrara]

I haven't dived doubled up aluminum tanks so I don't know. However I use AL 80's for deco and stage bottles and even though they are pos when empty they also go nose down (severely). Put 50% helium in one and goes streight up (upside down).

[O-ring]

thethumper once bubbled...


He's always on vacation. But I'l PM any how
Anyway, after looking at the pics I think you can move the bands up on the tanks a little. The other stuff listed is also good to try and I can't think of anything else to try.

I do have a set of Catalina AL80 doubles, but mine aren't the funky new 3300 psi neutrally buoyant ones, but are just plain old S80s. I don't have any trim problems with mine and dive dry with about 6# on a weightbelt if I don't carry my ~6-7# negative AUL canister with an SS bp. My other doubles are steel 72s and I don't wear any weights with them. I am planning a 6# v-weight for the AL80s to get weightbelts out of my life for good, but haven't done so yet. In a wetsuit (I usually dive a 5mm gold core with hooded vest and gloves), I don't wear any weights but am somewhat too negative when I carry my light. I decided to live with it until I get the cash thrown together for a nifty little HID and can stop carrying my water heater sized AUL light.

Anyway, the difference is probably in the tanks since the S80s are pretty much standard AL80 stuff...they swing from a couple pounds negative each when full to around 4# positive each when empty (hence the weightbelt). From what I remember, the C80s are pretty negative (around 6# each??) full and, if they do what they say they do, swing to neutral when empty, no?

[thethumper]

YA BUM

Thanks.... The photos on my site are actually predive. I moved the bands up to the point there was 1/8" of inner band exposed above the shoulder. I'm gonna try moving the wing to the bottom most eyelets to move the wing as high up as possible. Maybe moving the boyancey closer to the back of my head will help..... Oh I can't pass this one up..."Too bad I'm not Blonde" :mean: