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pdqaltair 05-07-2019 05:17 PM

Re: Jack Lines
 
Quote:

Originally Posted by Scandium (Post 2051600530)
You clip yourself into the bow cleat with a ~4-6ft tether? So if you fall off you'll be hanging from it underneath the bow of the boat, or along the side? How do you get back up? Are you alone, or do you rely on someone stopping the boat and pulling you up? BoatUS did a test and I believe they found you have about 60-90 sec to stop before drowning becomes a risk, so I would make sure this is all clear and set up properly.

I hope you did not take my statement that way, because I meant the reverse.

You clip to a jackline that ends 4-5 feet aft of the bow, to prevent falling forward. You can still reach the bow, of course, because sometimes you must. I then clip down low to a toe rail or railing, if I need to work at the bow. I would be sitting--it's hard to fall over a lifeline that way. I've done this with the short leg doubled; even with the bow playing submarine, you can't fall off.

Going to the bow in heavy weather is never pretty. Scooting rather than walking is often smart. There is no stand-up plan that is mistake proof.

paulk 05-07-2019 05:17 PM

Re: Jack Lines
 
We have webbing that replaced SS wires. The webbing is nice because it doesn't roll underfoot if you step on it. We rig them between a padeye on the foredeck and mooring cleats on the stern quarters. (We don't need the mooring cleats for anything else when we need jacklines rigged.) If they're polyester UV is not going to damage them much.

pdqaltair 05-07-2019 05:20 PM

Re: Jack Lines
 
On outboard powered boats there is an additional reason to end the jacklines well forward of the transom; if you fall of the back you could be chopped to death. I'd rather drown.

No, you are not likely to go off the back when the engine is running, but it could happen.

colemj 05-07-2019 06:30 PM

Re: Jack Lines
 
What about dyneema webbing?

We currently have a set of West Marine 1" polyester webbing jacklines. I've never been happy with them, but jacklines on a catamaran are not as critical (don't jump on that - I'll explain later). 1" polyester webbing has a breaking strength of ~1,500lbs. This is the same as 7/64" dyneema line, which is spiderweb-thin. There would be no issue with rolling under foot, and no issue with being in the way. The only issue might be actually finding it to clip on to.

Dyneema line has become very cheap. Particularly if you buy cutoffs, which is just fine for most jackline applications. I just bought 60' of 1/4" Endura 12 for $15.

So who here would feel comfortable with 7/64" jacklines? They are the same strength as 1" polyester webbing and won't roll under foot. For you metric fans, that is 2.5mm.

Jacklines on a catamaran only need to keep one from reaching over the edge. They will never really take a giant load, and one has so many other options for obtaining stability while stumbling around - bimini frame, grab rails, shrouds, simply falling toward the centerline, sitting down on the tramp, etc.

Our jacklines get run up the center of the boat, which puts them 8-10' from the edge of the boat. If one did fall, they would not reach the edge of the boat, so the jackline would only experience the load of the person slipping, and not a load of a person being dragged through the water.

The most dangerous part of going on deck in most catamarans is that short distance from the front of the cockpit to the front of the cabin house. This short side deck is usually wider than that on a monohull, and has the shroud located right there. Once forward of the cabin house, one is on a very wide deck, and even sunken in a trampoline. So there is ~8-10' between cockpit and solid bimini grab holds and the expanse of the foredeck that one must pay particular attention to. Luckily, the shroud is located in the middle of this distance, so that provides a good hand hold. Again, the jackline is 8-10' away from the edge, so there is no danger of going overboard.

For this short zone, we rig lines from the stern cleats, up to the shrouds at chest/middle height, and down to a bow cleat. These lines can be made tight, and don't interfere with the sails. This is serves as a high lifeline. Now, there is a nice hand hold outboard to use, and if one did somehow fall outboard, they would likely fall onto this lifeline.

As for the cockpit, we have nothing, and don't wear tethers or vests there. I'm not sure how we could even fall out of the cockpit - it is sunken, wide, and deep. We would have to be lifted 5' in the air and thrown 12-20' sideways to even come close to leaving the cockpit.

Mark

colemj 05-07-2019 06:43 PM

Re: Jack Lines
 
Definitely remove the jacklines when not needed. UV isn't even the real driver - they are just in the way and dirt magnets otherwise. Devise your system so that they are easily installed, removed, and stored. Webbing is great for this - rolls up into a tiny package.

If you determine that jacklines are needed whenever you are sailing, then leaving them in place seems more reasonable, though.

We think of jacklines as passage-making gear. Day sailing, or even a short over-night in planned weather we don't rig them because we are rarely on deck, and both of us can easily be up and active if there was any need to go on deck. However, for us all lines are led to the cockpit, so going on deck is a rare thing anyway. If we do need to be on deck, it is usually for a reason that being clipped to a jackline is a valuable thing.

Mark

RegisteredUser 05-07-2019 06:45 PM

To me...jacklines can double as handhold lines...rigged chicken/safety bars.
I would like to be able to wrap an arm and/or leg around and hug it tight..if ever needed.
Top of my boat is an obstacle course...even at quiet anchorage...:)
If rough...scoot crawl..always weight down low..and hold the fk on to sumping..
I run a 1/2" line to mast then to bow cleat..is off the deck and easy aid when moving

I love dyneema but id want simething large enough i can squeeze the juice out of

bristol299bob 05-07-2019 06:51 PM

Re: Jack Lines
 
I rig webbing pulled tight as I can between dedicated hard points a foot back from the bow and 2 ft from the stern. After reading this thread I'll consider moving them even further from each end.

I also have 3 hardpoints in the cockpit to directly connect tethers.

But I have come to rely on fixed tethers at workstations ... I have a fixed tether at the mast and one near the bow. The tether at the mast is quite comfortable (chest height) and easy to get steady and get the job done. The one on the bow ... well ... I'm secure, but thats all I can say. its the bow of a monohull afterall. For me, working at the bow of a monohull in conditions that require a tether is just not pleasant no matter how you slice it.

pdqaltair 05-07-2019 08:14 PM

Re: Jack Lines
 
Quote:

Originally Posted by colemj (Post 2051600580)
What about dyneema webbing?

We currently have a set of West Marine 1" polyester webbing jacklines. I've never been happy with them, but jacklines on a catamaran are not as critical (don't jump on that - I'll explain later). 1" polyester webbing has a breaking strength of ~1,500lbs. This is the same as 7/64" dyneema line, which is spiderweb-thin. There would be no issue with rolling under foot, and no issue with being in the way. The only issue might be actually finding it to clip on to.

1" polyester webbing suit able for jacklines is actually about 6500 pounds, once an allowance for stitching is made. World Sailing and ISO say 5000 pounds finished. (You can confirm by reading WS Offshore rule)


Dyneema line has become very cheap. Particularly if you buy cutoffs, which is just fine for most jackline applications. I just bought 60' of 1/4" Endura 12 for $15.

So who here would feel comfortable with 7/64" jacklines? They are the same strength as 1" polyester webbing and won't roll under foot. For you metric fans, that is 2.5mm.

Not 7/64, probably 1/4" to meet strength requirement. That is what APS does for the ones they make. In part this is because Dyneema does NOT stretch, making for higher forces than polyester. Additionally, the fittings will need to match the Dyneema line, about 8000 pounds.

Jacklines on a catamaran only need to keep one from reaching over the edge. They will never really take a giant load, and one has so many other options for obtaining stability while stumbling around - bimini frame, grab rails, shrouds, simply falling toward the centerline, sitting down on the tramp, etc.

Yes, they can. Stuff wave at 15 knots and see. Also, the wide cabin top and hard top are great places to fall from. I've been launched from the cabin top and it can be a LONG way (I had a PDQ before the tri in my avitar).

Our jacklines get run up the center of the boat, which puts them 8-10' from the edge of the boat. If one did fall, they would not reach the edge of the boat, so the jackline would only experience the load of the person slipping, and not a load of a person being dragged through the water.

The load of a person running/stumbling 12 feet considerably exceeds that of a 6' vertical fall. You can do the math. I've had harder stops on multis than any mono.

The most dangerous part of going on deck in most catamarans is that short distance from the front of the cockpit to the front of the cabin house. This short side deck is usually wider than that on a monohull, and has the shroud located right there. Once forward of the cabin house, one is on a very wide deck, and even sunken in a trampoline. So there is ~8-10' between cockpit and solid bimini grab holds and the expanse of the foredeck that one must pay particular attention to. Luckily, the shroud is located in the middle of this distance, so that provides a good hand hold. Again, the jackline is 8-10' away from the edge, so there is no danger of going overboard.

For this short zone, we rig lines from the stern cleats, up to the shrouds at chest/middle height, and down to a bow cleat. These lines can be made tight, and don't interfere with the sails. This is serves as a high lifeline. Now, there is a nice hand hold outboard to use, and if one did somehow fall outboard, they would likely fall onto this lifeline.

As for the cockpit, we have nothing, and don't wear tethers or vests there. I'm not sure how we could even fall out of the cockpit - it is sunken, wide, and deep. We would have to be lifted 5' in the air and thrown 12-20' sideways to even come close to leaving the cockpit.

Mark

Just sayin', watch the assumptions.

colemj 05-07-2019 09:32 PM

Re: Jack Lines
 
Quote:

Originally Posted by pdqaltair (Post 2051600602)
Just sayin', watch the assumptions.

OK, so I made a few assumptions. To whit:

1. We won't ever be stuffing our bows at 15kts while anyone is on deck. Seriously, do you think people cruise this way?

2. I won't be on our hardtop, or even our cabin top in serious weather. Why do you think someone will climb onto the hardtop in inclement weather? What reasonable person even rigs jacklines on their hardtop? If for whatever reason going up there was necessary, then the procedure would be a specific one, with a specific plan, and not rely on a general jackline.

3. 7/64" dyneema may be a bit light, but even 1/4" will not roll under foot. Still a viable alternative.

I disagree that a person taking a prat fall on a wide deck, or having one foot slip, or simply jerking quickly aside a few inches, considerably exceeds a dead fall of 6' coming short on a tether. This is probably easily shown through simple physics, but most people's experience is sufficient. I won't do the math, since I'm not the one questioning it. BTW, nobody is running to the foredeck. At least not anymore on a catamaran than a monohull, and nobody will be doing it for 12' on a catamaran, since the tether is 6'.

I'm with JeffH in thinking that stretch works against one in this case. As for end fittings, of course they need to be matched with the expected load. Otherwise, it is like cautioning against connecting anchor to chain with shoelaces - pretty much a waste of breath.

But what about dyneema webbing? Doesn't seem too expensive, won't roll underfoot, good UV and chafe resistance, and stronger than polyester.

Mark

pdqaltair 05-07-2019 10:17 PM

Re: Jack Lines
 
a. I've always sailed that fast. Some of it cruising, some just for fun. Heck, my PDQ would do double digits pretty easy, and my tri is faster. Why else have a multihull?
b. Each boat reefed from the mast. No big deal.
c. Yes, there were always hard points or jacklines on the cabin top. That's just good design, since a jam related to the mast or boom is always a possibility. I fact, rigged vertical jacklines, something like shrouds. Really nice when working on the hard top. No big deal.
d. Take your tether, tie it to a tree with 12 feet of slack, and run as though you tripped. It will hurt, a lot. It's just safety gear. If you don't actually take a worst case trip or stuff anything will work.

I like the idea of Dyneema. There are slackline companies that market limited amounts of Dyneema webbing. Try balancnecommunitee.com.


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