Length of spool line

[Amphiprion]

I don't know whether I never learned this or if I just forgot, but when doing decompression diving (presumably 130' +) how long should my spool line be? I've never needed to shoot a bag at depth, but do this on occasion where the decompression is a drift.

 

[rjack321]

How much drift? (how fast are you going to go away from the boat/site)

How deep is the bottom? (where you could shoot it)
What is your first deep stop? (where you could shoot it)
What's your deepest deco gas? (where you could shoot it)

Either 100ft, 150ft or 400ft are your choices depending on the dive and these issues.

 

[Druid]

Your line should be at least 1.5 times as long as your depth. So for 130' dive you need at least 195' of line.

 

[sea2summit]

Your line should be at least 1.5 times as long as your depth. So for 130' dive you need at least 195' of line.

What he said.
I use a spool to 100' or 150' in the quarry, anything else is a reel (try letting a spool play out for more than a minute and you'll understand).

 

[Cave Diver]

Your line should be at least 1.5 times as long as your depth. So for 130' dive you need at least 195' of line.

Ditto.

 

[rjack321]

Your line should be at least 1.5 times as long as your depth. So for 130' dive you need at least 195' of line.

What the heck for? Maybe you need this much line shooting a bag from the bottom of the English channel, but locally 99% of my dives I use a 100ft spool cause I'm not shooting a bag any deeper than 70ft (EAN50 switch depth). Yes we have current in Puget Sound but for most dives 70ft is <10mins up from the bottom. So at most you're a few hundred feet from the boat when the bag hits the surface.

 

[deepstops]

Standard practice in the S FL tech community is shooting the bag as we leave the wreck because the captain wants to be tracking us ASAP, not trying to estimate where bags will pop-up 20+ minutes into the deco schedule (where the 70' switch occurs).

Even in a moderate 1.5 knot current, 20 minutes equates to half a mile.

And yes, you want lots of extra line because there's often a large difference between the current on the top and the bottom.

 

[rjack321]

Standard practice in the S FL tech community is shooting the bag as we leave the wreck because the captain wants to be tracking us ASAP, not trying to estimate where bags will pop-up 20+ minutes into the deco schedule (where the 70' switch occurs).

Even in a moderate 1.5 knot current, 20 minutes equates to half a mile.

And yes, you want lots of extra line because there's often a large difference between the current on the top and the bottom.

From the bottom, you'd almost assuredly be using a reel not a spool I don't know what your profiles are, but for a dive like the HydroAtlantic you aren't 20+mins away from 70ft. You could practically shoot a 150ft spool from the bottom.

 

[Cave Diver]

What the heck for? Maybe you need this much line shooting a bag from the bottom of the English channel, but locally 99% of my dives I use a 100ft spool cause I'm not shooting a bag any deeper than 70ft (EAN50 switch depth). Yes we have current in Puget Sound but for most dives 70ft is <10mins up from the bottom. So at most you're a few hundred feet from the boat when the bag hits the surface.

I made that mistake. Once.

Our original plan had been to tie into a wreck, but the current didnt allow it. 3 dive teams did a hot drop in 4-5kt current in 220'. I had 150' of line on a spool, but knew with the amount of current we were drifting in that wasn't sufficient scope to pop a bag until we hit our 70' stop. With 4'-6' seas the boat didn't spot our bag until we were at our 20' stop and about 7 miles down current from our initial drop point. And yes, this was in S. Florida

Every dive since then has been with a spool or reel with sufficient line to hit the surface from 1.5 x the target depth.

 

[deepstops]

From the bottom, you'd almost assuredly be using a reel not a spool I don't know what your profiles are, but for a dive like the HydroAtlantic you aren't 20+mins away from 70ft. You could practically shoot a 150ft spool from the bottom.

There are a "few" other wrecks besides the Hydro Atlantic around here
And many of them are deeper so based on 220' average depth and 30 minute BT, yes, we are ~20 minutes into the deco schedule depending on the first deco gas (32 or 50).

I carry a 400' reel and two 170' spools and make the choice on what to use based on the depth and conditions.