Newbie Monterey weighting question

I'm a novice with only two logged dives in hawaii, where I wore a 3 mm shorty, had an Al 80 tank, and was weighted maybe just a teeny bit light at 16lbs. I am 6'5" and 250 lbs. This is my total diving experience up to now.

But I want to dive in Monterey, with basically the same tank, but probably with a 7mm farmer john wetsuit with a half mil skinsuit, bibbed hood, gloves and 7mm booties. I know I'm going to need a lot more weight, maybe in the 35 - 40lb range, but with no experience up here in the cold water, I'm a little uneasy not having a good idea of how much weight to try.

Any suggestions would be greatly appreciated.

Hey H,
I would recommend going out with a local DM first time out... maybe one of the shops close to the water (in Monterey) that knocks out some of your rental and logistics issues. As far as weighting goes it'll be easier to add and subtract weight and try different types of BC's and fins all in one day.
I'll let some of the DM's and Instructors make a guess to your starting out weight.... See you around the Breakwater.

Ben

Maybe a refresher course in cold water diving?

Yes, I will be with a DM, and I'm sure I'll get good advice about weights. It's just that, never having done any diving in cold water I feel I wanted as many perspectives from knowledgeable people that I could get. Especially since I've been reading about how different bouyance control is in cold water with a lot of neoprene from tropical conditions with light neoprene.

That's a really good idea to go down to Monterey maybe a day early and check out some equipment, get more opinions.

The best we can do is give you the same range as you mentioned. You will probably go in and out of the water several times to get the correct weight. I do a tune-up dive every year just to check things out...a lot of divers do a "tweak" day annually.

The bad news is that you will do the same routine if you dive 20 times this summer and you will shave several lbs off the belt, just because.

Buoyancy control will require a GREAT deal more attention than in a tropical suit.

Wazzup H,
Once you fine tune your buoyancy and ajust your trim for cold salt water, there are some awesome dive sites to explore in Monterey... 1 Draw back ! All that weight...
I am 6'1" 205 - 208, 7mm full suit, 6/5 mm vest & hood, 3mm socks, 7mm boots, 5mm gloves, AL 80, With that config. I carry 33.6 lbs. Breaks down to 3.6 on the ankles, 24 dumpable in the BC and 6 in trim pockets just below my shoulder blades, Makes a real nice attitude for swimming as well as an easy heads down when on the reefs...
So welcome to Monterey and to cold water diving, your gonna love it !

If you have all the gear and have access to a pool, you can get very close before going to the ocean. And adjusting weight in the pool is a lot easier.

Put everything on and say 30lbs on your weightbelt. Also have some extra weight in any form you'd like, either at the side or bottom of the pool. Get in the pool, and try to get neutral on the bottom (10~20ft) without putting gas in the BC. Add or subtract weight (just pick up in your hands / set down according to need) until you can.

Once you get the weight you needed to accomplish the above, subtract weight of the gas in your tank. For a full tank, about 5lbs, for a half full tank, 3lbs, for a tank at 500psi, none. This is your freshwater weight requirement.

Now add your weight 250lbs, the weight of all your gear minus weights, probably around 40lbs, and the weight you needed (let's assume 40lbs for example) giving you e.g. 330lbs. Or you can jump on the scale fully geared up including your freshwater weights and use that total.

Seawater is about 2.5% heavier than fresh water, so take 2.5% of your above total weight, (for the above example 2.5% would be 8.25lbs) and add that to your freshwater weight requirement and that will be your saltwater weight.

Do bear in mind that if you are uncomfortable on the surface you will be breathing heavily and may have slight difficulty descending with correct weighting. If that's the case, relax, and breath out all the way and you will be fine. Diving grossly overweighted "just in case" can be dangerous and at best tiring and inefficient.
Also remember to vent your BC early and often when ascending. During ascents you will need to vent a lot more often compared to warm water.

paulwlee:

Once you get the weight you needed to accomplish the above, subtract weight of the gas in your tank. For a full tank, about 5lbs, for a half full tank, 3lbs, for a tank at 500psi, none. This is your freshwater weight requirement.

Click to expand...

To expand on this point, you want to have just enough weight to be able to stay down at the end of the dive, when you have about 500psi left. If you are doing your weight adjustment with a full AL80 tank at 3000psi, you have about 5 more pounds of air than at 500psi. If you are neutral with the full tank (and empty BC), you will need to add 5 more pounds of lead when diving. You will start the dive 5 pounds negative, balanced by putting air in the BC. At the end of the dive, you will have used about 5 pounds of air, and have let pretty much all of the air out of the BC.

The basic technique is right, and I've used it myself, BUT:

paulwlee:

IOnce you get the weight you needed to accomplish the above, subtract weight of the gas in your tank. For a full tank, about 5lbs, for a half full tank, 3lbs, for a tank at 500psi, none. This is your freshwater weight requirement.

Click to expand...

ADD the weight of the gas in the tank, not subtract. And a full AL80 has closer to
6 pounds of air.

paulwlee:

Seawater is about 2.5% heavier than fresh water, so take 2.5%
of your above total weight, (for the above example 2.5% would be 8.25lbs) and add
that to your freshwater weight requirement and that will be your saltwater weight.

Click to expand...

2.56% for typical sea water. Some almost enclosed systems (most notably the Red Sea)
are a bit denser. That .06% is about a pound and a half of lead.

Executive summary: Get neutral in fresh water with a full tank. Multiply the weight of the
system (diver, all gear including tank and lead) by .0256, and add that much lead. Add six
pounds for the molecules in the tank.

Chuck