why more than 60-100' of line for a DSMB?

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tep

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I've been shopping for a DSMB and spool. I've never needed one, so far, but I know the time will come. Especially with some of the fun currents we get in San Diego kelp.

But a few dives ago I was in a current with a new buddy, and his DSMB was very helpful for our safety stop. No current at depth, but we moved at least 50 yards between coming up and holding at the safety stop. We would have been OK without it, but I know it made a huge difference for the boat to know where we were coming up. We ended up at least 75 yards downstream from the boat.

I'm convinced.

I keep seeing line capacities of 150-250 ft for a spool.

I pretty much never dive deeper than about 60-90, and I believe that I'll only want a DSMB when I'm on the ascent or at the stop.

Why should I have more than 100' of line on a spool for this?

Or am I completely wrong in every respect?
 

elan

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I never needed more than a 100ft spool for my DSMB and that has some line removed so realistically it holds about 80ft of line. 200ft gets into a realm of a small reel for me.
 

boulderjohn

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What tbone1004 said is true, but for what you describe as your plans, a 100 foot spool should be all you need, and you will probably want to take 10 feet or so off of it to make it more manageable. If you ever get to the point of needing much more line, you will be at the stage of your diving where you will have multiple spools/reels anyway.
 

Nemrod

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I have several spools but the two I use the most, one has 30 feet of line and the other has 60 feet of line (as of my last trip). The 30 feet spool is attached to a 3 foot sausage (SMB with over pressure) and the 60 feet spool is attached to a 5 foot sausage (DSMB). I can shoot the 30 footer at 30 feet on ascent and wind it to15 for safety stop. The 60 footer I can shoot from 60 feet on ascent for minor deco stops and then my safety stop. Since I am generally on drift with the current I do not need a lot of scope. But, yes, sometimes the surface current (and wind) is different from even at 15 feet, so you want a little extra over your intended depth of use.

I have to be able to deploy my sausages with one hand so I attach them to the spool. I got tired of dropping the damn spool with 150 feet of line on it while dealing with other more important things like my wife, or my camera or for that matter, myself and then futzing around with trying to recover 150 feet of tangled up line.

James
 
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RobPNW

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I've never used a DSMB and feel I need one for the equipment setup I'm putting together. I would be using it for recreational diving for now and want to keep things simple and minimal on my kit. I assume I can rig up a couple bungee loops on the side of my BP and stuff the rolled up device in there for storage.

On the topic of spool vs reel, is there a small and user friendly reel that I could use for this but also use for basic wreck dives as well and not carry two devices? Or would you recommend a compact spool solely for the DSMB for most of my dives and if I know I'm diving on a wreck, bring an extra reel for that?

Seems the color standards vary depending on location, but is it safe to say a solid orange one will be considered a standard, non emergency marker for most common situations?

What would be a sweet spot between being large enough to see on the surface but not be to much bulk on a streamlined gear setup? I'm guessing 1.5 meters?

I see most have a dual purpose valve for your inflator or oral inflation. Any pluses and minuses for the ones that have the open end with a "duck bill"? I assume that would be for exhaling into from your regulator exhaust?

I see they have an over pressure valve in case you get over zealous with inflating them. Depending on the depth of inflation, this thing is going to try and expand considerably. Is it normal for that excess air to bleed out of the over pressure valve on the way up, by design, or is the diver underinflating it at depth, anticipating expansion on ascent?

Any preference on color of line?
 

NothingClever

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I've never used a DSMB and feel I need one for the equipment setup I'm putting together. I would be using it for recreational diving for now and want to keep things simple and minimal on my kit. I assume I can rig up a couple bungee loops on the side of my BP and stuff the rolled up device in there for storage.

On the topic of spool vs reel, is there a small and user friendly reel that I could use for this but also use for basic wreck dives as well and not carry two devices? Or would you recommend a compact spool solely for the DSMB for most of my dives and if I know I'm diving on a wreck, bring an extra reel for that?

Seems the color standards vary depending on location, but is it safe to say a solid orange one will be considered a standard, non emergency marker for most common situations?

What would be a sweet spot between being large enough to see on the surface but not be to much bulk on a streamlined gear setup? I'm guessing 1.5 meters?

I see most have a dual purpose valve for your inflator or oral inflation. Any pluses and minuses for the ones that have the open end with a "duck bill"? I assume that would be for exhaling into from your regulator exhaust?

I see they have an over pressure valve in case you get over zealous with inflating them. Depending on the depth of inflation, this thing is going to try and expand considerably. Is it normal for that excess air to bleed out of the over pressure valve on the way up, by design, or is the diver underinflating it at depth, anticipating expansion on ascent?

Any preference on color of line?

Since you’ve never used a DSMB, I’m going to assume you‘re not thinking of bringing along another spool with the intention of laying line in the wreck. If true, one spool and DSMB should be enough.

A reel can be a lot of line. There are some itty-bitty reels out there but they seem gimmicky to me. Halcyon makes a really trick spool that has a small handle (Defender Pro). The largest holds 60m of line which means you can shoot from 40m in a current and not get dangerously pulled up. Not critical for recreational diving (but critically important for technical diving). That 60m Defender Pro still fits in a leg pocket.


An orange DSMB is pretty universal for “Here I am decompressing / drifting / practicing” but make sure others (the captain and crew) understand what your DSMB color(s) mean. Some captains hardly ever see a DSMB so you don’t want them freaking out assuming something‘s wrong and trying to haul you up like a fish. It happens. If you let go of the spool and they come up empty handed, then all kinds of pandemonium ensues.

I think 1.5 meters is good. That will still fit in a mask pocket. I hate dangly stuff so if I’m in a stripped down ST rig in a simple exposure suit (no pockets), I put a spare mask pocket on my waist belt and carry my DSMB and spool there. Some divers have a DSMB and spool flopping all around like it’s symbolic of experience. If I tried hard, I could probably come up with a slick bungee system that doesn’t require a pocket but I’m working on other problems these days so the mask pocket works for now.

The duck bill models need to be fully inflated to ensure air doesn’t leak out. Some folks don’t like them because in a current they can start taking on water through the duckbill and displacing air out the OPV. Water-logged DSMB = not good.

When at depth, fill that sucker as much as you can without losing control of your buoyancy and let the OPV do its thing as the air expands on the way up. You want that DSMB standing proud at the surface, not wilting or trying to impersonate a carrot in the garden. I’ve seen a bunch of DSMBs only partially filled at the surface with only about half (or less) of the DSMB above the water. You don’t want that. If you find that when you surface, work to correct it at first opportunity.

Your DSMB is an effective communication device. Make sure not to mumble when you talk.

Dealer’s choice on line. I have white and orange. Both work.
 

inquisit

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Yes, you can count on the expansion to help the fill. No need to completely fill at depth, which also pulls less prior to release. A little more than a third full is all you need from 66 ft / 20m, etc.
 
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