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Re: want to build a trapeze [Re: Robi] #154198
09/07/08 05:51 AM
09/07/08 05:51 AM
Joined: Jul 2006
Posts: 1,147
Bay of Islands, NZ
W
warbird Offline
old hand
warbird  Offline
old hand
W

Joined: Jul 2006
Posts: 1,147
Bay of Islands, NZ
Quote
You know something funny! That image was originally posted by me and those were the trap lines I had/used on my blade. They were built by Trey Brown from Team Velocity Sailing.

WOW atleast give credit where credit is due warbird!


: )

I just grab images when I see them and use them if I need and hold them on file for others and pass them on when people ask..

I figure a picture tells a thousand words....and others, like me need all the help they can get.

By the way, did I tell you guys that image was Robi's?....they were off his blade....

-- Have You Seen This? --
Re: want to build a trapeze [Re: warbird] #154199
09/07/08 09:56 AM
09/07/08 09:56 AM
Joined: Jan 2004
Posts: 62
K
KMarshack Offline
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KMarshack  Offline
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K

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Posts: 62
How much do you allow for line creep? If you want the handle X off the deck, how much shorter do you make it to get to X after hanging on it for a few days.
Wouter.
Why do you place a loop at the bottom (after the handle) to attach to the ring or shackle? Why not just the fisherman's knot?

Thanks,
Ken

Re: want to build a trapeze [Re: KMarshack] #154200
09/07/08 10:01 AM
09/07/08 10:01 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
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bvining  Offline
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If you use a high tech line like Amsteel it doesnt creep once the knots and splices have set. And I dont think any movement due to the splices setting is going to be noticable in the handle height.

Re: want to build a trapeze [Re: KMarshack] #154201
09/07/08 11:38 AM
09/07/08 11:38 AM
Joined: Feb 2004
Posts: 3,528
Looking for a Job, I got credi...
scooby_simon Offline
Hull Flying, Snow Sliding....
scooby_simon  Offline
Hull Flying, Snow Sliding....
Carpal Tunnel

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Quote
How much do you allow for line creep? If you want the handle X off the deck, how much shorter do you make it to get to X after hanging on it for a few days.
Wouter.
Why do you place a loop at the bottom (after the handle) to attach to the ring or shackle? Why not just the fisherman's knot?

Thanks,
Ken


I've made mine out of V12 and just add an open tail so I can make adjustements if I need to; just tie a hitch around the trap wire to stop it creaping when it's not under load.


F16 - GBR 553 - SOLD

I also talk sport here
Re: want to build a trapeze [Re: KMarshack] #154202
09/07/08 01:51 PM
09/07/08 01:51 PM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
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Wouter  Offline
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I build my trap lines with no compensation for creep. Creep didn't appear to be a problem in the sets I have made so far.

I use a loop as that allows a fishermans hitch around any ring or shackle which is perfectly secure and allow quick and easy assembling/disassembling of trapeze line components. I learned from rock climbers about how practical closed loops are in securing lines. Through the same route I learned about the double figure 8 knot.

Additionally, this double figure 8 knot can double up as the knot holding the handle in place. It is nice and thick.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: want to build a trapeze [Re: Wouter] #154203
09/07/08 02:21 PM
09/07/08 02:21 PM
Joined: Nov 2005
Posts: 1,203
uk
TEAMVMG Offline
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uk
OOOERR - knots in synthetic line. isn't there some sort of techno law against that?


Paul

teamvmg.weebly.com
Re: want to build a trapeze [Re: TEAMVMG] #154204
09/07/08 03:34 PM
09/07/08 03:34 PM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
Carpal Tunnel
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West coast of Norway
You cut the strength of the line by a large amount with a knot, but that hardly matters if there still is strength enough for the application. Just the way I see it.

Re: want to build a trapeze [Re: Timbo] #154205
09/08/08 01:55 AM
09/08/08 01:55 AM
Joined: Aug 2007
Posts: 21
New Zealand
G
GoGecko Offline
stranger
GoGecko  Offline
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G

Joined: Aug 2007
Posts: 21
New Zealand
More on trapeze setups
If I have the trapeze set up for optimum length upwind s the wind increases
and I am trapping from behind the rear beam I am too high on the boat so would adjustable trapeze set up solve this or does it not matter if too high.
when on a screaming reach.

Thanks

Re: want to build a trapeze [Re: GoGecko] #154206
09/08/08 02:28 AM
09/08/08 02:28 AM
Joined: Feb 2004
Posts: 3,528
Looking for a Job, I got credi...
scooby_simon Offline
Hull Flying, Snow Sliding....
scooby_simon  Offline
Hull Flying, Snow Sliding....
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Joined: Feb 2004
Posts: 3,528
Looking for a Job, I got credi...
Use adog bone.

Set the high end to be your upwind setting and then you should be about right on the lower for reaching at the back of the bus.


F16 - GBR 553 - SOLD

I also talk sport here
Re: want to build a trapeze [Re: TEAMVMG] #154207
09/08/08 04:33 AM
09/08/08 04:33 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
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North-West Europe

Quote

OOOERR - knots in synthetic line. isn't there some sort of techno law against that?



If it works its works, right !

(Also a reason to use the double figure 8 knot as that knots has the line make bends with a larger inner radius and thus reduces its break strengh less. There is a whole science associated to knots and there are a few very attractive knots that leave most of the line strength unaltered.)

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: want to build a trapeze [Re: Wouter] #154208
09/08/08 04:36 AM
09/08/08 04:36 AM
Joined: Sep 2004
Posts: 2,584
+31NL
Tony_F18 Offline
Carpal Tunnel
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How does splicing affect strength?
Why would you ever use a knot when you can splice?

Re: want to build a trapeze [Re: Tony_F18] #154209
09/08/08 07:30 AM
09/08/08 07:30 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
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Why open the door when standing on your feet when you can also open de door while standing on your head ?

So the answer to your question is simple. If using knots is sufficient, then why invest extra effort to make a splice in a 2-stage dyneema line (mantle and core) ?

2-stage dyneema is cheaper then D12 and other non-core spliceable line and the outer mantle protects the dyneema fibres in the core better; this is good for long term use.

Basically, using knots is easier, cheaper, faster and more durable in the long run.

Why use a splice where a knot is sufficient ?

Wouter

Last edited by Wouter; 09/08/08 07:30 AM.

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: want to build a trapeze [Re: petealmquist] #154210
09/08/08 08:14 AM
09/08/08 08:14 AM
Joined: Jun 2001
Posts: 778
Houston
carlbohannon Offline
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carlbohannon  Offline
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Houston
You forgot an important trade on line vs wire. Line does not form little "meat hooks" to tear up your hands when strands break.

Re: want to build a trapeze [Re: Wouter] #154211
09/08/08 09:13 AM
09/08/08 09:13 AM

A
Anonymous
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Anonymous
Unregistered
A



perhaps we have over complicated this for a new guy... <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Re: want to build a trapeze [Re: ] #154212
09/08/08 02:25 PM
09/08/08 02:25 PM
Joined: Mar 2008
Posts: 201
Adelaide, South Australia
simonp Offline
enthusiast
simonp  Offline
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Adelaide, South Australia
Quote
Why use a splice where a knot is sufficient ?


because it is prettier? we all like a bit of bling on our boats too!

simon


Simon
BLADE F16 AUS405
Re: want to build a trapeze [Re: simonp] #154213
09/08/08 04:24 PM
09/08/08 04:24 PM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
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Okay,

How effective is bling-bling up near the hound fitting ?

And how do the splice guys hold de handle up ?

The loop with a knot avoids the need for a timble on the lower end of the trapeze line.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: want to build a trapeze [Re: Tony_F18] #154214
09/09/08 05:26 AM
09/09/08 05:26 AM
Joined: Sep 2007
Posts: 571
Hamburg
Smiths_Cat Offline
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Hamburg
Quote
How does splicing affect strength?

No at all, a splice guarntees 90 to 100% of the breaking load. The breaking load reduction of a knot depends on the rope material. For Dyneema it is said to be around 80% reduction, hence 20% of your breaking load are still usable.

If you have a 500kg breaking load trap line, you can still use 100kg on it, which should be sufficient.

Dyneema creeps about 5%, but if you pre stretch the rope (e.g. with the main sheet) you can solve this problem. After this 5%, I didn't notice any creep on the trap lines. Some suppliers deliver pre stretched ropes as well.

Cheers,

Klaus

Re: want to build a trapeze [Re: Smiths_Cat] #154215
09/09/08 05:41 AM
09/09/08 05:41 AM
Joined: Sep 2004
Posts: 2,584
+31NL
Tony_F18 Offline
Carpal Tunnel
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Splices are prettier and reduce windage, obviously <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />
Seriously though, ropes can sometimes get caught behind knots so thats another reason to splice.

Re: want to build a trapeze [Re: Smiths_Cat] #154216
09/10/08 03:11 AM
09/10/08 03:11 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
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Wouter  Offline
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Quote


No at all, a splice guarntees 90 to 100% of the breaking load. The breaking load reduction of a knot depends on the rope material. For Dyneema it is said to be around 80% reduction, hence 20% of your breaking load are still usable.

If you have a 500kg breaking load trap line, you can still use 100kg on it, which should be sufficient.



I can't say that I find any justification for these claims in my personal experience.

After a capsize I easily put 100 kg on the line, yet I have never broken one.

Also a splice ONLY get's a high breaking load fraction when ALL parts of the loop are prevented from bending to a radius less then 7 times the line diameter. In effect, if you don't use thimbles in all spliced loops then the wrap around any object will reduced the breaking strength of the spliced loop to much less then 90%.

But we can do numbers on these things as much as we want, fact of the matter is that using knots is sufficient on a 3 mm 500 kg mantle-core dyneema line as proven by myself (90 kg in the nude) overy 7 years now. With me are several others who have done the same to their traplines. The theoretical data needs to be in agreement to that. Having only 20% break strength left doesn't appear to satisfy the real life experience.


Added to this is my cascaded downhaul setup where the later stage is experiencing 300-400 kg load and also using knots to secure it to the blocks. Again, you have good knots (with a high fraction of breaking strength left after knotting) and bad knots. I learned alot when I was still active with stunt kites. Good knots are : Double figure 8 knot, fishermans hitch, sheet bend and the bloodknot. With these you can do everything and not loose more then 50% of the breakstrength in the worst case scenario due to the knot itself.

But my best advice is to learn and remember the "double figure 8 knot" this is truly a good knot. Has the lowest break strength reduction in my opinion, makes very tidy/smooth knot and makes fixed loops. Won't come undone when shook about untensioned like the sheet bend sometimes does.

Wouter

Last edited by Wouter; 09/10/08 03:28 AM.

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: want to build a trapeze [Re: Wouter] #154217
09/10/08 06:24 AM
09/10/08 06:24 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
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Posts: 12,310
South Carolina
Quote
Quote


No at all, a splice guarntees 90 to 100% of the breaking load. The breaking load reduction of a knot depends on the rope material. For Dyneema it is said to be around 80% reduction, hence 20% of your breaking load are still usable.

If you have a 500kg breaking load trap line, you can still use 100kg on it, which should be sufficient.



I can't say that I find any justification for these claims in my personal experience.

After a capsize I easily put 100 kg on the line, yet I have never broken one.

Also a splice ONLY get's a high breaking load fraction when ALL parts of the loop are prevented from bending to a radius less then 7 times the line diameter. In effect, if you don't use thimbles in all spliced loops then the wrap around any object will reduced the breaking strength of the spliced loop to much less then 90%.

But we can do numbers on these things as much as we want, fact of the matter is that using knots is sufficient on a 3 mm 500 kg mantle-core dyneema line as proven by myself (90 kg in the nude) overy 7 years now. With me are several others who have done the same to their traplines. The theoretical data needs to be in agreement to that. Having only 20% break strength left doesn't appear to satisfy the real life experience.


Added to this is my cascaded downhaul setup where the later stage is experiencing 300-400 kg load and also using knots to secure it to the blocks. Again, you have good knots (with a high fraction of breaking strength left after knotting) and bad knots. I learned alot when I was still active with stunt kites. Good knots are : Double figure 8 knot, fishermans hitch, sheet bend and the bloodknot. With these you can do everything and not loose more then 50% of the breakstrength in the worst case scenario due to the knot itself.

But my best advice is to learn and remember the "double figure 8 knot" this is truly a good knot. Has the lowest break strength reduction in my opinion, makes very tidy/smooth knot and makes fixed loops. Won't come undone when shook about untensioned like the sheet bend sometimes does.

Wouter


Layline.com has a line "punisher" that is a long steel I-beam, a hydraulic press, and a load meter. I don't have the exact numbers but they clearly confirm that knots definitely weaken lines more than splices.


Jake Kohl
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