What is a dive plan on a shallow wreck?

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allanbranch

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Location
Panama City Florida
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Okay, go easy on me, OW cert here + nitrox with 12 dives outside of the class. My dive buddy is my 15-year-old son.

I hear "plan your dive," but what does that mean? So help me understand dive planning with a scenario that is real...we're on a dive boat, pulled up to a wreck, it's a tug boat, the depth is 75', the top of the tug is 55', water temp is 81 at depth, viz is 15', no current.

What do we plan as dive buddies before we get into the water?

What brought this up was a recent dive where we got turned around on a wreck; the boat was anchored outside the wreck about 20'. The viz was super low, probably 12', and we have passed by the anchor line. I knew we were close to the anchor line but couldn't find it. We looked around but still couldn't see it. Got a little worried and locked arms...then slowly ascended to 35' watching our dive computers for accent rate. As we ascended, we kept looking around and finally spotted the anchor line. I told myself at 20' I was going to deploy my smb. This little "hmmm" moment has made me want to ensure we're following best practices in these situations. Being ignorant is tough.

Appreciate the wisdom.
 
Okay, go easy on me, OW cert here + nitrox with 12 dives outside of the class. My dive buddy is my 15-year-old son.

I hear "plan your dive," but what does that mean? So help me understand dive planning with a scenario that is real...we're on a dive boat, pulled up to a wreck, it's a tug boat, the depth is 75', the top of the tug is 55', water temp is 81 at depth, viz is 15', no current.

What do we plan as dive buddies before we get into the water?

What brought this up was a recent dive where we got turned around on a wreck; the boat was anchored outside the wreck about 20'. The viz was super low, probably 12', and we have passed by the anchor line. I knew we were close to the anchor line but couldn't find it. We looked around but still couldn't see it. Got a little worried and locked arms...then slowly ascended to 35' watching our dive computers for accent rate. As we ascended, we kept looking around and finally spotted the anchor line. I told myself at 20' I was going to deploy my smb. This little "hmmm" moment has made me want to ensure we're following best practices in these situations. Being ignorant is tough.

Appreciate the wisdom.
fro dive planning treat it as a square profile and stay within NDL -youll know your bottom time and so when you get to the bottom of the mooring line check you time and make sure you only go far enough along the wreck to get back to the mooring line in time -as suggested use a reel until you get more confidence and experience-you can use a strobe and clip it to the mooring line if it makes it easier -most importantly have fun
 
For me dive planning can be split into 3 areas: Gas planning, Deco planning (this includes non-deco dives), and Logistics. In addition to this you would do a buddy check which includes things like signals and equipment quirks.

  • Gas planning - how much do you have; what is it, what is its MOD; how much do you need in reserve, rule of thirds? Minimum gas? do you need a turn around pressure because you want to return to the shot.
  • Deco planning - acent rate you plan to do, and saftey stops you plan on doing, what's the maximum no deco limit, will you have manditory deco. At the end of all this you want a max bottom dive time, and a total dive time so the surface know when to expect you.
  • Logistics - stuff about the site; any compass bearings you need to know; who is leading; who is doing the DSMB, are you both doing one; where is the anchor in relation to the site (good boats will be able to tell you on the surface); what is the goal for you and your buddy, i.e. if one of you wants to shoot off to make sure they see the boilers and the other is a photographer only interesting in anenomes, learning this on the surface might avoid a seperation.
These lists are not exhaustive, lots of this can be done a long time before kitting up or even on the boat, which helps you mentally prepare. As you get more experienced you will add and subtract to this list depending on the dive and buddy. Hope that helps.
 
Great questions and good to see you're learning and doing some interesting diving.

The simple dive plan for a wreck is to plan it at the maximum depth, 22m/75ft. Look that up on your dive planning tables.

Next thing is to decide how you ascend. Can you come up anywhere using an SMB (don't care); or is it a MUST return to the shot/anchor line; or is it a SHOULD return to the shot/anchor line. The answer to this will tell you how critical it is to find the shot/anchor line again:
  • If it's a don't care about returning to the shot dive, then you can bimble around the wreck until your time's up, then ascend under an SMB.
  • If it's a MUST return to the shot/anchor dive, then you must allow for time to return to the shot, basically allow for HALF of the NDL time to go out from the shot and the other half to come back to the shot. Therefore you must be aware of how to get back to the shot line.
    • If the visibility's not great the best way is you tie off a line on the shot anchor and reel it out. You then will have to cut short your bottom time -- half of the NDL time for that depth -- and once time's up, you reel back in to return to the shot line, untie, and ascend.
    • If the visibility is OK, then you will need to constantly "back reference" so that you know where the shot line is at all times.
    • It is possible to put a bright strobe marker on the shot line which makes it a little easier to see the shot line
  • A should return to shot depends on what "should" mean; will probably be the same as MUST return, but you've more scope to come up under an SMB if you need to.
Have fun :)
 
Other people gave you good advice.

Mine would be ASSUME that you will not find the anchor line to ascend. You and you son should be able to make an ascent without locking arms and without visual references. Saying that is easy, developing the skills to do that will probably take time and practice, but it will be worth it when you both have accomplished that. Locking arms was the right thing to do if there was any doubt about your skills in staying together on an ascent. Nothing really wrong with that, but it should not be necessary.

You BOTH should know how to run an SMB and deploy from depth - even if you get separated or you die. To be safe, you need to develop the skills to handle things when they go sideways.
 
GUE EDGE for a dive like this could look something like this, assuming all divers are in AL80s

Goals we're going to go see the Ships bell on the bridge
Unified team: I'm going to be the captain of the dive and run decompression. Diver 2 willl deploy the SMB. We'll travel side by side and diver 2 will be on my right.
Equipment match: head to toe match to make sure we have everything like the SMB etc.

Exposure: This will be a 20 minute dive at 75ft
Decompression: "Our MDL at 75ft is 50min, we'll use a min deco ascent profile and our first stop will be at 40ft our total ascent time is 8 minutes" (on nitrox 32)
Gas: Our min gas is 1100psi and our gas strategy is half-usable, our turn pressure will be 2100psi (assuming AL80s for everyone)
Environment: The visibility on this dive might be a bit low, and there is boat traffic in the area so if we come up off the line we'll need to make sure to get the SMB up before 20ft.

1660757438962.png



There is also GUEPLAN which is a mnemonic for:
goals and objectives
unified team strategies
Equipment strategies
Parameters: depth, distance, duration, direction, gas and decompression strategies
Logistics
Assessment
Nutrition
 
GUE EDGE for a dive like this could look something like this, assuming all divers are in AL80s

Goals we're going to go see the Ships bell on the bridge
Unified team: I'm going to be the captain of the dive and run decompression. Diver 2 willl deploy the SMB. We'll travel side by side and diver 2 will be on my right.
Equipment match: head to toe match to make sure we have everything like the SMB etc.

Exposure: This will be a 20 minute dive at 75ft
Decompression: "Our MDL at 75ft is 55min, we'll use a min deco ascent profile and our first stop will be at 40ft" (on nitrox 32)
Gas: Our min gas is 1100psi and our gas strategy is half-usable, our turn pressure will be 2100psi (assuming AL80s for everyone)
Environment: The visibility on this dive might be a bit low, and there is boat traffic in the area so if we come up off the line we'll need to make sure to get the SMB up before 20ft.

View attachment 738588


There is also GUEPLAN which is a mnemonic for:
goals and objectives
unified team strategies
Equipment strategies
Parameters: depth, distance, duration, direction, gas and decompression strategies
Logistics
Assessment
Nutrition
Whilst a very interesting and informative post, that style of planning requires a fair amount of training, certainly beyond that of the OP's current training and experience.
 
Whilst a very interesting and informative post, that style of planning requires a fair amount of training, certainly beyond that of the OP's current training and experience.
I think if you strip it of the dogma it's actually a useful tool. If you account for all those things, or can explain why they are N/A, you have a pretty good start on a dive plan, regardless of skill level.
 

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