Need Help with weighting for my Fusion dry suit

[sfdiver140]

Hey Bubbletrubble,
Very interesting what do you think about weight distribution? Do you think a weight belt is a good idea, with 28lbs in my BC and all equipment on I could not stay down. I added 6 more pounds and still I was to light I had to carry a rock. I am looking at total weight of 40lbs in order to sink and add air in the suit to keep me warm. 40 is a lot of lead in the BC I like the idea of distribution of weight. I am thinking of using a 20lb weight belt and adding the other 20-lbs total in ankle, trim weights and BC weight a total of 40-lbs. I don't think I need ankle weights they fit at the top of the rock boots and my fins are slightly negitive but its 4-lbs that is easy to carry. The story from the diveboat operator not understanding because most drysuiters use their suit for boyancy so why did he get to the surface with an empty suit with no air in it? must have been using the bc. If so should have been very cold especially in monterey. I do agree that it should be easier to have weight distributed when diving dry. This same dive instructor keeps telling me that I should have dropped weight over my wet suit maybe that is why between both bits of advice I am having trouble.....thinking I should be dropping weight and putting it all in my BC. I keep thinking what am I doing wrong. What do you think. Others are welcome to chime in. Thank you Bubble and to all helping. steve

 

[Bubbletrubble]

@sfdiver140: Normally, with these kinds of situations, I give the instructor the benefit of the doubt. But I think it's quite clear that your instructor has given you two bad pieces of information which are really impacting your learning curve on the drysuit. Your next step is simple. Find a new dive instructor.

 

[sfdiver140]

Hey bubble good advise will do that tomorrow.....thanks

 

[JanK]

One more thing: I think that using both ankle weights and trim pockets might be counterproductive. The ankle weights rotate you feet down, trim pockets rotate you feet up (head down). So you're just spreading your weight away from the centre of gravity, making it harder to rotate (due to increased moment of inertia). Not to mention that having weights on your ankles means more work and that is the antithesis of diving. As the late Douglas Adams so eloquently put it in his essay Riding the Rays:

One of the curious features of scuba diving is that your suit and equipment seem so heavy and cumbersome and unwieldy on the surface - which is one of the things that tends to frighten beginners - but once you descend below the water level everything begins to flow smoothly and easily, and the trick is to exert yourself absolutely as little as possible, in order to conserve oxygen. It is, almost by definition, the least aerobic sport there is. It won't make you fit.

I also think that you might not actually need the weight in trim pockets (depending on where they are). My experience with the Fusion is also limited to 8 dives in this year, so I'm still in the beginning of getting used to it, just like you. So don't take this as definite advice, but my experience might help you figure things out.

With the wetsuit I use 4kg on the belt and 3kg on each side in the integrated weight pockets of my BCD (for a total of 10kg) and I mount the tank as high as possible. This gives me perfect trim: slightly feet up on the surface, horizontal at mid depths and slightly feet down at greater depths (the reason for the trim shift at depth is that neoprene compresses all over, so you lose buoyancy in the legs and the buoyancy to compensate for that is added in the BCD, thus shifting the centre of buoyancy up the body).

On the first few dives with the drysuit I used 10kg on the belt and 4kg on each side of the BCD for a total of 18kg. I noticed that my feet were constantly hanging down, so I thought that due to the fact that the Fusion hugs your legs, but cannot do as much "hugging" on the body, the centre of buoyancy is higher than with the wetsuit. To offset that I moved 2x1kg from the BCD to tank cam band.

But in the last two dives I started to realise that I have actually been diving wrongly. The great catch and the big difference between a wetsuit and a drysuit is that in the drysuit the trim is dynamic - it changes with body orientation, whereas with the wetsuit it is static (depending on just the depth, as described above). IOW assuming you are in perfect trim while horizontal, if you rotate feet down, the bubble (and with it the centre of buoyancy) will shift towards your head and this change of balance will push your feet even further down. And rotating your feet up will have the opposite effect, moving the bubble towards your feet and pushing your feet even higher up. So the equilibrium is unstable (think of a ball on top of a hill).

When I tried staying in the horizontal position I found out that my feet were starting to float up, constantly threatening to get me into inverted position, so I had to work to keep them down. To get into equilibrium I needed to drop my legs to the point where a lot of air had drained out and I was in a slightly head up position.

So I am starting to realise that my centre of gravity might have actually been to high and for the next dive I'll move the 2x1kg from the tank cam band back into the BCD and I think it will be easier to get a good trim. If that doesn't help I still have almost 25 cm of available offset for the tank (in our parts steel tanks are the norm, so it does affect the trim). And only after that I'll start looking at ankle weights.

One more thing which might throw you (it certainly threw me). The Fusion (at least with the thick fleece undergarments that I use) is very slow in shifting the bubble. In the drysuit course I had relatively thin undergarment and both the trilaminate and the neoprene suits that I used were slightly oversized. The bubble shifted position almost instantly. But with the Fusion the speed is much lower. I actually timed it and it takes 8 seconds for the feet to stop deflating after rotating quickly from horizontal to vertical position. This means that there's a significant delay in the effect that the change of position has on the trim. Something similar to the delay in reaction on buoyancy when you inflate/deflate your lungs or BCD.

 

[sfdiver140]

Hi Jank thank you so much, that is great information. My trim pockets are located on the BC just below the shoulder blades. I checked and my trim pockets can take up to 5 lbs (2.26 kg) in each pocket - adding more weight to the trim may distribute the weight better....I have to get in to the water. I think that it is great that you have a fusion we can compare notes on what works. When I dove neoprene dry suit it was just like a wet suit -- put on a weight belt and go no ankle weights or trim. My ankle weights are 2lbs each .907kg
You really bring up some good points especially the observation about the trim changes with orientation so true. I spoke to a White field rep and he said that this is why he only uses enough air to make him warm and then uses his BC - interesting. So this evening I shifted more weight in to the back trim pockets and less in the BC pockets and that made a big difference in just wearing it. If feels far more balanced the real proof is in the water. I am going to try to get to the water this weekend. Once I determine the amount of weight that I can dive with then the position of weights can be determined. I am going to try 39.5lbs 18kg. I am 205lbs 92kg what is your weight to wear 18 kg if you don't mind me asking. Let share information it may make working out kinks in diving with the Fusion easier. Again thank you for the post and great information. Steve Where do you dive? Living in Ljubljana, Slovenia it seems you are almost land locked.

 

[sfdiver140]

Hey Jank you will have to check out a post I got from 'fdog'
Very informative.....

Everyone that switches to a drysuit, from a wetsuit, is boggled by the extra weight. Insulation keeps you warm, and it takes lead - more than you think - to sink the insulating airspace.

Here's how to tell what you really need:
Go to the local pool with a buddy.
Put on your suit along with all your normal insulation, hood, and mask.
Open shoulder dump all the way.
Wade around in neck-deep water for about 5 minutes. This "shrink wraps" your suit.
Return to shallow end.
Lay flat on water surface. Make yourself rigid like a board.
Have your buddy slowly pile weights on your chest & belly.
Test is complete when you float with a full breath, and begin to sink after exhaling more than half your lung capacity.
Write it down.

...This is the total ballast it takes to sink you.

As a point of reference, I weigh 198 lbs, and am 6'2". I have abnormally large lungs. Using similar undergarments as yours in a Fusion, I need a total of 41 lbs of ballast. <note: I've seen that regular folks without my 9 liters of lung capacity need 35-36 lbs>

Now, take your total ballast, and add/subtract the following amounts:

Backplate -5 lbs
Regular BC +1 lb
Regulator -1.5 lbs
Can light -2 lbs
Aluminum 80 +4 lbs
Steel HP 100 -2.5 lbs

After doing all this, you will have the amount you need to wear on a weight belt, in fresh water.

Now, to confirm this:
Attach a cylinder at ~500 psi or less to your BC.
Put everything on.
Again shrink-wrap suit.
Dump all air from BC.
You should be neutral at half a breath, just under the surface (sink w/ full exhale, rise w/ full inhale)
Adjust lead until this happens.
Write it down.


For salt water, dry everything out, then gear up and weigh yourself complete as you would get into the water. Then, multiply that weight by 0.0256. This is the weight you should add for correct weighting in salt water.

...Whew! That's quite a bit, but, worth the investment to stay warm. Hope this helps!

All the best, James[/SIZE][/B][/B][/B]

 

[sfdiver140]

So here is an update.....a local dive shop had a get to know your equipment night at a local high school pool it was very cool. The owner was so helpful she is so great. I was able to get down in fresh water with 28lbs. In a 13 foot pool I am having problem with bouyance. I just may need more practice and or deeper water. Maybe it is just me but does anyone think it is a pain to vent our your left shoulder?? vs the BC where you just pull the dump?. I have never had so much trouble with any part of SCUBA in my 16 years of SCUA life. It is a sport that just came so easy and this drysuit thing is kicking my butt. I will try 32lbs in the ocean and keep practicing. The crazy thing is I am no way toasty warm like people say. The insanity is I am not dry I am damp from sweat well I think it is sweat all I know is I am damp. Every one talks about how the Fusion is the best ever, some are selling their DUI but not me so far it is the center of my frustration. The best part of a wet suit is you put it on and forget it....you just dive you can be upside down any way and not problem. The BC vents are so easy to use. I will keep trying it must be me!! I am doing something wrong because I am the only person who grips about the Fusion so I shall keep trying. The jury is still out on this Fusion dry suit. Oh and now the stitching aroung the neoprene shell around the neck is coming out just not what I expected.....so watch some one may get a great deal on a slightly used Fusion drysuit.

 

[Bubbletrubble]

I think your issues with the Fusion are not brand- or model-specific. Going from a wetsuit to any drysuit necessitates doing a proper weight check and correctly positioning ballast to help promote horizontal trim. Then you have to learn how to operate the drysuit. You should know that every drysuit diver has the same issues making the transition from wet to dry. It's a humbling experience. Be patient with it. Your comfort will steadily increase with practice. You'll probably find that owning a drysuit will translate into more diving opportunities in your local waters.

With regard to difficulty venting from the left bicep...
This may sound strange, but don't think of it as raising the left bicep. Instead, think of it as momentarily rotating your shoulders so that the right shoulder is down and the left shoulder is up (given an initial horizontal position). This movement positions the left bicep exhaust valve at the highest point of the drysuit and should facilitate venting gas from inside the suit. Once you get the hang of this, I think you'll recognize the convenience of being able to manage an ascent hands-free.

 

[TSandM]

I've heard lots of people who move from a wetsuit to a dry suit say that it feels like learning to dive all over again. It can certainly take a lot more weight! In my Fusion, with the MK3 undergarment and a Thinsulate vest under it, I use 31 total pounds of ballast, and I'm 5'4" and 120 lbs. I wish I could use less, but that's what it takes with an LP95 tank (with aluminum, it would take even MORE).

Position in the water is important in a dry suit, because you DO only have one dump. But the Fusion makes life easier than other suits, in a way, because it discourages air trapping anywhere. I have found buoyancy control much easier in my Fusion than it was in either of my other two dry suits. The key to it is anticipation -- vent before you think you need to, because the bubble gets away from you quickly. I also endorse the idea of putting only enough gas in the suit to take the squeeze off, and using the BC for primary buoyancy control, at least until you are facile with the suit.

In all dry suits, the condensation from sweat and transudation from the skin will condense on the inside of the suit, rendering the very outside of your undergarment damp. If you are wetter than that (if your base layer is wet) then something is leaking. First possibilities are the seals (and realize that where you are the wettest bears little relationship to where the leak is, and far more to what your posture is in the water. The wet will run down to whatever part of you is lowest while you are diving). Dump and inlet valves can leak, too, if they are not properly installed.

It sounds as though it might be well worth your while to spend a day with a good instructor and get some help with this stuff.

 

[JanK]

@sfdiver140: for reference, I'm a 181cm and 87kg and need 18kg of weight. But of course the weighing depends on your body density and undergarments used (and if you're using a neoprene suit also on the thickness of that).

As Lynne has pointed out, diving a drysuit is almost like learning to dive again. Think about it: what's more or less the only thing about diving that really just needs a certain number of dives to really get comfortable with, i.e., that you do without thinking. I'd say it's buoyancy control with the BCD and lungs. Now you add another term into that equation, a term that has more variables than the previous two. Of course you need to practice! Did you "get" buoyancy after 6 dives?

About dampness: The outside of my undersuit is polyester and it has beads of water on it when the drysuit comes off. I also find that the fleece inside of my undergarment is damp. I'm certain that the suit does not leak and that the moisture is only from sweat - the dampness is uniform around the inside, including the legs, not to mention that I have licked and tasted and smelled the water to make sure it wasn't seawater . That's why I intend to get another thin layer to put next to the skin to wick the moisture away from the skin and keep it drier. And also because it's much easier to wash a couple of thin pieces of cloth than the whole thick undersuit.

And I certainly agree that it much more fun to use a wetsuit - I like the feel of water on the skin and the fact that you can turn and spin and float upside down, emulating 0 gravity, but I have resigned to having that only in the tropics. BTW Slovenia is not landlocked - we have around 40km of coast with a few nice diving spots. It takes around 1h to drive from home to the coast and around 2h to drive to the coast of Istria in Croatia, where the visibility is generally much better. But the temperatures are simply too low for me to enjoy diving in a wetsuit - all year round there's a thermocline at around 15m where the temperature drops below 20C and another one at 25m, where it can go as low as 15C. So instead of freezing and cursing with the wetsuit, I will be warm and practice (and sometimes curse ) with the drysuit.