Going From Fresh Water To Ocean (lead)

[Yoyoguy]

Ok everyone. I am planning a trip to N.C. this summer in July time frame. It appears the water temps will be 75-80F at 100 feet which is quite warmer than I am used to diving. I regularly dive lakes/quarries where 7mm wetsuit with 7mm hood and gloves are needed. Due to this I used to carry 22-24lbs lead which would give me pretty good buoyancy/trim. I converted to a bp/w setup and now I have 8lbs lead on my belt with my back plate and a weighted STA. I also recently started diving steel 100s as well which allows me to ditch the weighted STA. From what I gather, I will likely be diving a 3mm or 5mm suit in the ocean this summer. I think it will likely be the 3mm suit. Now there is that general rule of 3lbs per 1mm suit. So for a 7mm that would be 21lbs which was pretty dang close to what I needed. Going with that logic a 3mm suit will be 9lbs which is a solid 10lbs less, however, going to the ocean typically adds 5lbs due to the salt water so that means really about 4lbs coming off my belt. That would only leave me 4lbs on my belt. My concern is being able to swim up my rig in a total wing failure. I will be diving with lots of buddies but I do like to plan. 4lbs left on my belt is not a whole lot of weight to drop. This means worst case scenario I could be swimming up a full 100 steel with a steel backplate. I am considering buying an aluminum plate for this very reason. This would allow me to move 4lbs to my belt Thoughts? Am I being overly cautious? I know the real issue would be with diving double steels with out back-up buoyancy(drysuit) so maybe I am making I am presenting a non-issue with single tank. The other thing I fear is when I get down there to do a weight check and I end up with no weight on my belt...again this may be a non issue.

 

[Bigeclipse]

Anyone care to comment about my thoughts on getting an aluminum backplate?

 

[macado]

There is no real mathematical solution to your question. A proper weight check is going to be the best way to do this. I personally wouldn't go out and buy an aluminum plate just for this reason alone unless you're finding yourself to be extremely negative. I mean you can buy an aluminum plate for like 65 bucks without a harness at DiveGearExpress.com so it's not a huge investment.

Complete wing failures are honestly a bit uncommon. Even if the wing does fail it will usually hold / trap a bit of air. If you're worried about it then take a liftbag or large SMB with a spool as backup inflation device and "reel yourself up.." Not pretty but it works..

Having said that, a lot of people regularly dive HP100s with SS backplates in North Carolina with full 3mm/5mm wetsuits. In this setup I actually don't carry any ditch-able weight at all and am pretty negative but I could conceivably swim this up in a complete wing failure.

I've estimated I can swim up -10-14lbs. I've tested it before. Specific Example: Aldora Divers in Cozumel where I typically dive an steel HP100 or HP120 with a SS backplate/wing and a 5mm wetsuit. I'm honestly like boat anchor but even without air in the wing I can swim this up fine.

In my opinion it is not an issue as you're not going to be negative enough for it to be a problem. But like everything your results may vary some people are more negative/positive than others.

Here's a very simplistic overview. There are other factors and variables that I have probably left out
Full 100 HP ~ -8.5lbs
SS backplate -6lbs
Regs ~ -2lbs
--------------
-16.5lbs
+5 lbs (buoyancy from brand new full 3mm wetsuit - I'm guessing here..)
-11.5lbs negative

Obviously the buoyancy of the wetsuit in question will depend on lots of favors such as age, thickness and size but let's say your wetsuit provides ~5lbs of positive buoyancy (Honestly..I have no idea..)

Another thing to consider, a 3mm suit at 100ft is not a 3mm anymore. Same thing with a 5mm. That is one of the specific reasons why I would choose to wear a 5mm over a 3mm in 75-78f water.

 

[Bigeclipse]

There is no real mathematical solution to your question. A proper weight check is going to be the best way to do this. I personally wouldn't go out and buy an aluminum plate just for this reason alone unless you're finding yourself to be extremely negative. I mean you can buy an aluminum plate for like 65 bucks without a harness at DiveGearExpress.com so it's not a huge investment.

Complete wing failures are honestly a bit uncommon. Even if the wing does fail it will usually hold / trap a bit of air. If you're worried about it then take a liftbag or large SMB with a spool as backup inflation device and "reel yourself up.." Not pretty but it works..

Having said that, a lot of people regularly dive HP100s with SS backplates in North Carolina with full 3mm/5mm wetsuits. In this setup I actually don't carry any ditch-able weight at all and am pretty negative but I could conceivably swim this up in a completely wing failure.

I've estimated I can swim up -10-14lbs. I've tested it before. Specific Example: Aldora Divers in Cozumel where I typically dive an steel HP100 or HP120 with a SS backplate/wing and a 5mm wetsuit. I'm honestly like boat anchor but even without air in the wing, I can swim this up fine.

In my opinion it is not an issue as you're not going to be negative enough for it to be a problem. But like everything your results may vary some people are more negative/positive than others.

Here's a very simplistic overview. There are other factors and variables that I have probably left out
Full 100 HP ~ -8.5lbs
SS backplate -6lbs
Regs ~ -2lbs
--------------
-16.5lbs
+5 lbs (buoyancy from brand new full 3mm wetsuit - I'm guessing here..)
-11.5lbs negative

Obviously the buoyancy of the wetsuit in question will depend on lots of favors such as age, thickness and size but let's say your wetsuit provides ~5lbs of positive buoyancy (Honestly..I have no idea..)

Another thing to consider, a 3mm suit at 100ft is not a 3mm anymore. Same thing with a 5mm. That is one of the specific reasons why I would choose to wear a 5mm over a 3mm in 75-78f water.

thanks for the info. I figured I might be over analyzing but I just want to be prepared. I am still on the fence about 3mm vs 5mm because I dove once in 81F temps and only wore my bathing suit and was completely fine for a 45 minute dive but maybe 75F is a bit cooler and 5mm would be necessary. Do you think hood and gloves are needed?

 

[macado]

thanks for the info. I figured I might be over analyzing but I just want to be prepared. I am still on the fence about 3mm vs 5mm because I dove once in 81F temps and only wore my bathing suit and was completely fine for a 45 minute dive but maybe 75F is a bit cooler and 5mm would be necessary. Do you think hood and gloves are needed?

3mm vs 5mm is hard to judge since it's based on personal tolerances. Your dives may be a bit shorter in NC due to depths so you can probably get away with a 3mm but I personally like to be warn. You can always flush the suit with water if you feel like you're too hot. Can't fix too cold if you only bring a 3mm with you and nothing else.

I wouldn't bother with a hood at all. Gloves yes. The mooring lines can have hooks on them from fishermen and wrecks can have sharp edges if you happen to pull yourself through a door way. Buy a pair of work / garden gloves at Home Depot/Lowes (Firm Grip Latex-Coated Cotton Large Work Gloves-5083-48 - The Home Depot)

 

[boat sju]

5 degrees is a significant temperature differential. At 75 deg I'd want a 5 mm but at 80 just a 3 mm. I'm with macado on this, I'd rather be warm in the 5mm.

Can you get in a pool with the gear you intend to use? The math for the buoyancy between fresh water and salt is easy and accurate. (Usually about 6 lbs.)

 

[drrich2]

"The mooring lines can have hooks on them from fishermen and wrecks can have sharp edges if you happen to pull yourself through a door way."

Quick note: When I dove with Olympus Dive Center out of Morehead City, N.C. last August, they didn't tie off to mooring buoys. They put down an anchor, with an anchor line, and thus nothing was 'growing' on the line (e.g.: stinging organisms, razor clams) unlike one might find with mooring lines.

I'm not knocking gloves; just mentioning something of note if the O.P. is focused on a N.C. trip.

Richard.

 

[Carl_F]

5 degrees is a significant temperature differential. At 75 deg I'd want a 5 mm but at 80 just a 3 mm. I'm with macado on this, I'd rather be warm in the 5mm.

And I dive just a rashguard & board shorts in 80+. 3mm in 75F in Hawaii was just fine even on long dives. I'm good with a 3mm down to 65F or so though I might add a skin under the 3 mil at the lower end of that spectrum.

All personal preference.

 

[TMHeimer]

Simply, as always I agree with just doing a weight check. As for water temps., 75-80F for me means body suit or rash guard as they call it. Unless you can find a pool before you go to NC you'll just have to estimate what wetsuit to wear. OR, you could check the temp. and dive the good ol' Hudson, add a few degrees perhaps, and go from there......

 

[macado]

"The mooring lines can have hooks on them from fishermen and wrecks can have sharp edges if you happen to pull yourself through a door way."

Quick note: When I dove with Olympus Dive Center out of Morehead City, N.C. last August, they didn't tie off to mooring buoys. They put down an anchor, with an anchor line, and thus nothing was 'growing' on the line (e.g.: stinging organisms, razor clams) unlike one might find with mooring lines.

I'm not knocking gloves; just mentioning something of note if the O.P. is focused on a N.C. trip.

Richard.

Yes sorry. My mistake. I was confusing Florida moorings and other permanent moorings. The crew / mates in NC will tie into the wreck. There still can be hooks, fishing lines and sharp edges on wrecks though so a thin pair of gloves is not a bad idea. Not needed for thermal comfort.