Current lines behind the boat?

[Peter_C]

I searched the world wide web and did not find much info on current lines. We will be diving off the Northern California coast (Sonoma, Mendocino, and Monterey)from a 14' Zodiac and want to deploy a current line when needed. I bought an 11"x14" yellow Polyform A1 series buoy and some yellow 1/2" hollow braid poly line in a 250' length. I am not sure the line is going to be large enough to drag ourselves back up to the boat though. Also not really sure to cut it at 100' or 150' or anything between 100-250'?

What are others using for rope type, color and diameter and how long of a line do you trail?

Thanks for any advice :cool2:

 

[Gen San Chris]

Good question, I do not know the answer to that one at all!

 

[dannobee]

We have 200' of 3/8" poly braid and a small boat fender that is held in a deck locker. If the dive site is remote or we know the current is running, pretty much all of it is thrown overboard as soon as we set the anchor.

As we gear up, we keep an eye on the line, checking for tangles (rare), and how long it takes to go "all out" to gauge the speed of the current. Although it's attached inside the deck locker, it's also cleated off to the transom.

The only thing I'd change is the color (ours is light brown). Hi-vis yellow would be a LOT easier to spot, although when surfacing it seems you spot the boat, then the fender, and swim to it as the poly is obviously at water level. Hi-vis yellow would make it easier for other boaters to see if the dive site is popular.

Even 1/4" poly would be plenty strong to pull yourself back to the boat. 3/8" or 1/2" is strong enough for the whole group to hang on and pull themselves back to the boat.

One more thing, on my little inflatable I use 100' of 1/4" poly and an even smaller fender, but rarely throw it out (I just use the boat for Point Lobos and nearshore stuff). It's stored in a rip-stop nylon bag in the under seat bag.

 

[Walter]

How strong are the currents? How good are your navigation skills?

Strong currents indicate a longer line. Poor navigation skills indicate a longer line. A line that's one inch short of what you can reach is too short. I would leave the line intact, but only let out about 100 ft of line. If you come up behind the line, the person left on the boat can always let out more.

It's best to plan your dive so that you never need to use the line. Have it deployed, just in case, but don't rely on it. When you start relying on the line, you start coming up farther and farther behind the boat until you eventually come up behind the current line.

½ inch line is fine as a current line.

 

[Nemrod]

I usually run out a 100 to 150 foot line made from ski rope poly. I have a dive flag float on the free end with flag and a couple of sliding floats knotted in place to keep the line up on the surface so fisherman do not run over it and foul their props while I am below. They get really mad when they get it all wrapped up on their lower units. Then the USCG came by one day and wrapped it all up in their props and snapped my line. They wanted me to go down and get it off of their shaft, I told them no, they ran over it, they can get it off. That was some years ago behind my Novurania Cancuro 420 inflatable. They said it was a navigation hazard, I told them they were supposed to stay clear of dive flags, one on my boat and one on the line seems like they should have figured it out being as they are the "law" you would think. As I motored off they asked me, "what about your flag float" and I told them they can have it, I had another. It probably took them a while to untangle it all.

Yeah, it is a good idea to have a safety line or trailing line, the half inch seems a bit overkill and will use up a lot of room won't it? White or yellow seem easiest to see.

N

 

[dannobee]

...As I motored off they asked me, "what about your flag float" and I told them they can have it, I had another.
N

Nice! You should've said, "keep it, and when you get back you can explain to your CO how you ended up with a dive flag float wrapped up in your prop."

 

[captain]

Be sure the line floats, poly should float. Larger line is easier on the hands when you have to pull on it. Strength is not an issue even with line as small as 1/4". I used 100' but there was also always someone on the boat. I used and car tire innertube as a float.

 

[FredT]

If you have it in a 250' length, and a place to store it leave it at 250. More is better here. If you leave someone in the boat mark the line in 50' increments and deploy what you think you need based on current conditions, If you guessed wrong and get in trouble the person on deck can deploy the rest as needed.

My first one was a 2' x 3' x 3' Styrofoam bat section on about 300' of salvaged 3/8" black ply line. The float size was large enough to actually get on and out of the water to rest. It worked well, and came from beach coming and recovered bottom debris.

Many purpose rigged dive boats either keep their drift line on a reel, or in a self-draining trash can mounted on the stern. A 32 gallon trash can will hold about 300' of 3/4 in line in an untangled loose coil, self deploy freely, and store a norfloat buoy tied to the end. The bitter end will be firmly cleated off to the hull, so deployment consists of simply tossing the buoy and first 10' or so fo the line overboard. It'll self deploy after that.

Self floating line generally comes down to polypropylene (the cheapest) Spectra (not cheap but way strong per diameter) and Dyneema (Significantly stronger than spectra, and more expensive.) To give a strength Most trailerable boats can be safely towed with 3/16" braided dyneema, so if you have a serious storage space problem on board you can fit a LONG safety line in a gallon bucket using Dyneema. There are also specialty foam core ropes built for the fishing industry, but they are not generally available to the public.

 

[Nemrod]

Your 14 foot Zodiac is similar in size to our Cancuro 4.20 and I doubt you have room for 250 feet of poly 1/2 inch line, floats and flag. I used to slalom ski competitively and my experience with that is that a poly ski line is more than strong enough to hold a gang of divers even in current, the line can be purchased raw from rolls at many boat shops that cater to water sports people. As to being able to pull yourself up it in terms of grip, the adrenalin will take of that. I kept the line in a bucket on the port stern and still do. The anchor rode, three strand twisted nylon, goes in another bucket in the bow locker and still does.

You need several of these:

Kwik Tek Yellow Rope Float 3" Dia X 5" - F-5Y - BoatersWorld.com

And some of this:

ROPE > Three Strand - WebRiggingSupply

And something like this on the end:

http://www.leisurepro.com/Prod/Cate...ck/DescSort_0/Filter_6=533/AQUFD67.html?Hit=1

N

 

[Peter_C]

Nice! You should've said, "keep it, and when you get back you can explain to your CO how you ended up with a dive flag float wrapped up in your prop."

Now that would be funny to see someone explain.


We are not always going to have someone onboard, but there are some places on the North Coast that are somewhat protected. There are times we will probably bring our scooters too. The current can be very strong off the coast here, and it can change fast. Usually the direction does not change though. It is somewhat predictable by looking at the tide swings.

The roll of line is pretty small and can be palmed, but once unrolled it will be more of a handful. As anyone who has dove off an inflatable can attest to there is not a lot of room onboard, and tangled lines do not sound like fun. I will cut the line at 150 feet and see how I like it. The rope was only $24 dollars. Since it is bright yellow and hollow core it should float high in the water for others to see, so I am not going to worry about adding more floats to the line. My buoy is bright yellow too, although it will not have a dive flag, my boat will. Boat traffic is not a big issue since the North Coast is pretty remote so fewer boats venture out there. Hopefully in Monterey the boaters there understand current lines, but I am probably asking too much of a Budweiser chugging boater.