Buoyancy in 7 mil and how to be a good instabuddy -- kelp!

[Blyslv]

Heading for the San Clemente Islands aboard a 4 day live aboard. I'm going solo and joining a group. As a newbie, yeah, I'm a little nervous. To wit:

1. I've never dove in any sort of wetsuit, only a rash guard. I'll be renting a 7mil suit this trip and am wondering how it will affect my buoyancy. The shop is also giving me 28lbs(!) of weight.

2. I've reserved a 95cf. steel tank, hopefully I'll not be the one cutting short dives.

3. After reading the thread on 'instabuddies' and alarm bells, I want to be proactive. What things can an instabuddy do to put ones mind at ease? The gear will be new to me, the conditions new, and the people new. So keep my mouth shut when people are setting up, ask worthwhile questions, practice with my gear a few times seem like good ideas. Anything else? Do a buddy check, understand their hand signals, and don't drink all their wine at dinner.

In the water, clear the entry when jumping in, stay close by, and maybe a little above? Is it it a good idea to ask at least once how much air they have left?

4. I learned in metric... this will be PSI. Is it difficult to convert PSI to Bars?

5. I'm sure I missed many things, so can you let me know?

6. How worried should I be about getting tangled in kelp?

Thanks, I'm really looking forward to this!

 

[MikeFerrara]

The heavy wet suit is going to result in a greater change in buoyancy for a given change in depth. I would want to set aside time to get my weight and trim sorted out before a real dive.

Regarding units of measure, zero is still zero and half is still half but, a bar is roughly 15 psi (maybe more like 14.5).

The instabuddy thing...brief before the dive, debrief after the dive and plan dives that are appropriate for new buddies of your experience level. I like to start with a new buddy by doing one or more simple dives before taking on anything challenging..."simple" being relative.

I can't help with the kelp. I always wanted to dive in it but never quite got the chance.

 

[lemke]

When you go out to your first dive site, ask your buddy if he wouldn't mind helping you with a weight check. An honest and humble request usually makes a friend. I suspect someone over-hearing your query will pipe up, "Yeah, me too, me too!"

You'll do fine!

 

[Bopper]

You're gonna love San Clemente, and you're gonna fall in love w. kelp.

Regarding how to avoid being tangled in it, it's actually not that difficult underwater. Oftentimes as you swim through it your head and then shoulders will separate the strands of kelp for you. (The one caveat I would say though is that ppl who dive w. pony bottles mounted to the side of their tanks seem to get caught ALL THE TIME). When you're on top of the water and you need to do a surface swim, you'll want to swim over kelp on your belly while trying to push the kelp down with your arms and hands. You don't want to kick through kelp on your back as you're almost certainly going to get tangled with your tank and the kelp. And if you are tangled, try to gently backtrack from the direction you just came without twisting your body and creating the "spaghetti" effect where you become the fork and the kelp is the spaghetti. Most of the time just calmly reversing your direction will release the kelp. But always bring at least two cutting devices just in case you find yourself really tangled. In all the kelp dives I've done I've never actually had to cut through it.

 

[DivemasterDennis]

Re Instabuddy, this is from my blog here on SB:
When I have to dive with a "stranger," I pair up as early as possible, and talk to them. I ask about their last trip, their last dive, how long they have been diving. I look at their gear (brand new, rental, seasoned but well maintained, crappy, etc.) I tell them a little about me in the same areas. I ask if they have any objective for the dive ( want to go 100 feet, see a shark, find an eel, take pictures, etc.) It can all be a very friendly conversation. Within a few minutes we are not strangers. I then ( the divemaster sneaks out) work the conversation into a meaningful planned dive, with buddy check, orientation to each other's equipment, air use expectation and etc. I started this long before I had a professional rating and continue it to this day. I do it with students in continuing ed classess too. I have never had anyone object to the talk, and it leads to good planning, and good buddy habits in the water. Just be postiive, be nice, and be interested in learning about the other person. If there is a repetitive dive, let them know any changes you'd like, again in a positivie manner- such as the rambling buddy issue. Say "that was a great dive, but I was a little tense when you took off after that ray. I'm more comfortable if we stay closer together as a buddy team. Is that ok with you? Just be pleasant and positive. If they are totally wipeouts, then change buddies or make the best of it, or mention it to the DM or captain and let them make a "general" annoucement to the whole group.
DivemasterDennis

 

[Lorenzoid]

The thing about insta-buddies is that they don't always want to talk. Sometimes the best I could get was a nod or a shrug or an "Okay, fine." Just do the best you can, and don't let it throw you for a loop if, once in the water, the insta-buddy doesn't follow what you thought you agreed on. You've got a lot on your plate with unfamiliar gear, unfamiliar conditions and an unfamiliar buddy.

 

[Lopez116]

Regarding the weight - I just got my "cold water" buoyancy sorted out not too long ago. The steel tank will help immensely. With an 80 AL I dive with 24, with an 80 steel, I was good at 18. Didn't realize it would be that great a difference


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[Jim-SAR]

Disclaimer: I tend to dive over-weighted due to helping with students, and also being on the county dive team where we're searching on the bottom, so I'm used to diving heavy, and not perfectly adjusted.

When I go between a Steel-100CF and an Aluminum-80CF, I add(AL)/remove(ST) 10 lbs of lead and the buoyancy works out pretty well for me. I've attached a PDF chart of typical cylinder specs that shows the buoyancy when full and empty, and highlighted an 80-CF and 95-CF. As you can see, there's approximately 8 lbs difference when empty.

As for the 7mm wetsuit... I've been searching and I can't find any simple charts for a ball park figure. Here's a link to a weight calculator that'll probably get you within 3-5 punds. It was pretty close for how much weight I use when I'm diving in a drysuit with heavy undergarment. If you know what you normally dive with, for your conditions, then use the calculator and see how far off it is (+2 lbs, -2lbs, +3.5lbs, etc). Now, calculate for the new configuration, and then apply the difference you found before. This should get you really close.

Estimated Diving Weight Calculator

When it's all said and done, and you've got a weight value decided upon, go ahead and add another 3-5 pounds on there. Why? This is because you don't sound experienced in a thick wetsuit, or a larger tank (trim will be off), and the frustration of feeling restricted by the suit, you may feel like it's harder to breathe and you'll breathe a bit faster/shallower. Just being in a new/cold environment with a buddy you don't even know, in an area you don't know, and dealing with new obstacles (Kelp), it can all lead to you being a bit more anxious, and once again, that leads to faster/shallower breathing. When you breathe faster/shallower, you'll hold more air in your lungs and that will increase your buoyancy.

Enjoy the Pacific :cool2:

 

[mikeycanuk]

28lbs??

I'm not a big guy but I wear a XLS 7mm Aqualock. In a Cozumel with a steel 120 I was using 8lbs with a 7mm suit and 7mm boots but no hood/gloves. 28lbs is going to cause you issues and really weigh you down.


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[Bopper]

28lbs??

I'm not a big guy but I wear a XLS 7mm Aqualock. In a Cozumel with a steel 120 I was using 8lbs with a 7mm suit and 7mm boots but no hood/gloves. 28lbs is going to cause you issues and really weigh you down.


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I'm 5'9" 190 lbs and I used to wear 28lbs w. a steel 100 when I dove my 7mm AquaLock. That kind of weight requirement is not at all uncommon around here. In fact, a local day boat suggest 10% of your weight plus 7 lbs when trying to guesstimate weight requirements.