Weighting question... slightly too heavy or light?

[ls1dreams]

Hi all,

On my recent liveaboard trip, I found myself struggling between 2 increments of weights:

Me: 5'9, 160lbs or so
Weight options on board: 1.5kg each
Conditions: saltwater, 5mm wetsuit

With 3 weights (4.5kgs), my buoyancy was perfect underwater, but I found myself struggling at times to descend, and really having a hard time at the end of my dive staying down. At times I would have to go completely vertical and empty all air out of my bcd including dump valves. One dive I even blew through a safety stop because I couldn't stay down.

With 4 weights (6kg), I had tons more control and easily could descend or manage safety stops, but I did feel rather heavy on the bottom and had to use quite a bit of air in my BCD to compensate.

My gut feel is that in time I could get to 4.5kgs, but on about 50% of dives with that weighting I had issues. With that said, I did have a few dives @ 4.5kgs without issues that were great.

For now should I just stick with heavier weights? When do you decide to drop a weight and try again? (struggling to descend and blowing safety stops obviously stressed me out).

Unfortunately the boat didn't have any smaller weights (0.5kg or 1kg) which could have helped.

 

[scubadada]

You have to be able to hold your safety stop with a nearly empty tank, that is appropriate weighting. You have very few dives, you might try to reduce your weight again after you become a bit more experienced and comfortable diving. This is very common

 

[SeaHorse81]

If I have to err one way or the other, I'll err on the side that keeps me able to control my place in the water column at the end of the dive. In your position, I'd make a habit of doing safety stops on the mooring line in the interim if there is any doubt at all. Do a controlled ascent to the surface at the bow and then just swim back to the ladders from there.

 

[Dish]

What @scubadada and @SeaHorse81 said. Remember that the Safety Stop is not a Deco Stop. Blowing through it will not kill you where N2 is concerned, but there is value to your body if you conduct that stop.

That said, there is even more value to be able to maintain your position in the water column if something bad is happening on the surface. Corking into spinning props is one bad thing I wouldn't want to happen.

Hopefully your next dive trip will have something less than 3 lb weights to play with and you can fine tune your weight. With more dives under your belt, you'll figure it out.

 

[Neilwood]

I would always prefer to be slightly over weighted that under. You can always compensate for over but the only way to compensate for under weighting is finning.

As @Dish says, you need to be able to hold your depth incase of problems or issues that prevent ascent to the surface such as a deco obligation or boat overhead. Last thing you want is to cork in those situations.

The key though is to be slightly over not way over. That way you can still swim it up if you have an issue

 

[Marie13]

I've had a couple of experiences with being underweighted. It is not fun in the least. Best to be a bit heavy than a bobbing cork! You're definitely more in control.

 

[NorCalDM]

Couple things In your post that stick out to me first you stated that to stay down you had to let all the air out of your bc well if you have air in the bc it's going to expand as you ascend so you need to let it out to keep your stop. Second you said that some of the dives you did with the lighter weight went just fine so sounds to me the weight was spot on but need to manage the air in your bc better. The more weight you have on you the more air that you need in your bc to compensate but your buoyancy is harder to manage because that big air bubble is expanding and compressing as you go up and down so you are adding and releasing air continuously through your dive which is also using up your breathing gas.

 

[rongoodman]

I'd rather be a little heavy than struggle to hold position at the end of the dive. I can reach around and feel exactly how much gas is left in my wing so it's not hard to keep an eye on it.

 

[ScubaJill]

Look back at your dives where you felt less weight was appropriate and see if you wrote down your gas usage. If you have more gas (500-1000 psi) left than the other dives where you have issues maintaining your 15' stop, you're likely benefiting from the weight of the compressed air that is left. I like to fine tune my weighting because I hang close to the coral and use my breathing to change my depth. If I have too much weight, I add more air into the BC, and NorCalDM explained the trouble with that, but it's also exhausting trying to change depths when you're even slightly overweighted, particularly after a few long dives. I would buy some one pound soft weights and keep them with your gear. You can refine as necessary.

Also, watch the neoprene compression. It can affect your perception of being properly weighted as you change depths. (There were a couple of threads on this topic.)

 

[TMHeimer]

I agree with all. Better to be a little over. Get some 2 lb. and even 1 lb. weights and do a proper weight check. Sorry I can't do kgms. -- in Metric Canada divers still do Imperial except with water temperatures.