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-   -   What is the best line to use attaching trampolines? (https://www.cruisersforum.com/forums/f48/what-is-the-best-line-to-use-attaching-trampolines-166100.html)

Puget Dan 13-05-2016 10:05

What is the best line to use attaching trampolines?
 
Hi all, the lines attaching our trampolines to our Horstman Tri Star 38 have worn out. What kind of line do you attache the tramps to your boats with? They wore out in 2 years.

thinwater 13-05-2016 11:41

Re: What is the best line to use attaching trampolines?
 
Quote:

Originally Posted by Puget Dan (Post 2119344)
Hi all, the lines attaching our trampolines to our Horstman Tri Star 38 have worn out. What kind of line do you attache the tramps to your boats with? They wore out in 2 years.

If the rope wore out in 2 years, look at the attachments for wear points first. It is not the rope; even polyester should last a decade.

SVNeko 13-05-2016 14:42

Re: What is the best line to use attaching trampolines?
 
3/16" dyneema

AD28 13-05-2016 14:43

Re: What is the best line to use attaching trampolines?
 
TW makes a good point, and I'd add: use a single braid, whatever you use. I have found that single braids don't squeak, unlike double braids. I rather like Amsteel, myself

44'cruisingcat 13-05-2016 14:50

Re: What is the best line to use attaching trampolines?
 
Quote:

Originally Posted by thinwater (Post 2119395)
If the rope wore out in 2 years, look at the attachments for wear points first. It is not the rope; even polyester should last a decade.

Agree. We used multiple lashings of 4mm VB cord and no sign of wear yet.

Cheechako 13-05-2016 15:14

Re: What is the best line to use attaching trampolines?
 
I just used black nylon 3 strand. With that many attachments stretch wasn't an issue. It lasts a long time and is not expensive on a 300ft spool. I think mine were 1/4", maybe 5/16".

Stumble 13-05-2016 19:01

Re: What is the best line to use attaching trampolines?
 
I am using 7/64 dyneema. I like my tramp as tight as I can get it, so the low stretch line is necessary.

thinwater 13-05-2016 19:39

Re: What is the best line to use attaching trampolines?
 
I'm a moderate regarding stretch. While I respect all that Dyneema can do, I'm not sure it's for all things.

"I like the tramp as tight as I can get it." In my mind it makes LOT of difference what the tramp is made of. IF the tramp were Dyneema and lashed to a rigid deck with Dynema, the forces involved if you take a big fall onto the net are immense. Dyneema can thus increase wear on the tramp (I'd rather wear out the line than tear out eyes). It also depends on how big the tramps is. A large tramp will stretch and absorb energy, while a small tramp of the same construction would feel like wood.

So without knowing the dimensions and tramp material, it is impossible to give meaningful advise. For my ~ 8 x 14 tramp, 7mm polyester is about right. But I would chose something different for a different tramp.

Puget Dan 13-05-2016 22:28

Re: What is the best line to use attaching trampolines?
 
Thanks everyone, our trampolines are 9' by 7.5' with stainless hooks on 3 sides and a stainless bar in the front. We put the boat on the hard each winter and this winter the yard put it in a area that turned out to be a wind tunnel which I think caused a lot of the wear and tear.

Sand crab 14-05-2016 07:29

Re: What is the best line to use attaching trampolines?
 
The tramps on my tri were only fastened on the sides and they really sagged when you stepped on them. I added proper fore and aft eye straps when she was hauled last month and it is much better. Not all eye straps are created equal. The cheaper ones are just stamped steel with a hard edge which will chafe your rope. Is this what you have? I used the proper ones with round bales.

contrail 14-05-2016 08:08

Re: What is the best line to use attaching trampolines?
 
Quote:

Originally Posted by thinwater (Post 2119682)
I'm a moderate regarding stretch. While I respect all that Dyneema can do, I'm not sure it's for all things.

"I like the tramp as tight as I can get it." In my mind it makes LOT of difference what the tramp is made of. IF the tramp were Dyneema and lashed to a rigid deck with Dynema, the forces involved if you take a big fall onto the net are immense. Dyneema can thus increase wear on the tramp (I'd rather wear out the line than tear out eyes). It also depends on how big the tramps is. A large tramp will stretch and absorb energy, while a small tramp of the same construction would feel like wood.

So without knowing the dimensions and tramp material, it is impossible to give meaningful advise. For my ~ 8 x 14 tramp, 7mm polyester is about right. But I would chose something different for a different tramp.


Further on stretch, although I am not an engineer! Where you will be sailing can make a big difference. The fishnet style tramps on an FP, for example, are pretty uncomfortable and stretchy. On the other hand, they are great offshore as they provide little resistance to the waves that hit them. At the other extreme, the mesh used on Leopards (like mine) has probably less than half its area as holes and is not very stretchy. It's super comfortable but can get really hit hard by waves when offshore, as there is so little give. Many, including me, have lost a tramp or had it damaged offshore and some actually change out the tramps to an "offshore" fishnet when doing that type of sailing. I have no experience with tramps made of webbing, but have been told, second hand, that they may be the ideal compromise. Maybe someone, who has offshore experience with webbing, will chime in.

But, getting back to the attachment lines, I would think that the less stretchy the actual trampoline is, and the rougher your expected conditions, the more give you would want in your attachment lines. On the other hand, if your tramp is already stretchy fishnet, or you sail mostly in protected waters, why make things even more stretchy?

Roy M 14-05-2016 09:41

Re: What is the best line to use attaching trampolines?
 
2 Attachment(s)
I use NEW ENGLAND ROPES Spyderline Micro Dyneema Braid. This spiderweb sized, high-performance line has a Dyneema SK-75 core inside a polyester double braid cover that provides superior strength for its tiny diameter. Click on the pics to zoom in for detail. 500 pounds of humans on the bow nets is nothing. Over a year now with no signs of UV damage.

Cheechako 14-05-2016 09:54

Re: What is the best line to use attaching trampolines?
 
If your tramp is 9' x 7.5 ft, you probably have at least 80 attachments/eyes. If a 200# person falls on the trampoline,, the load on each line is maybe 2.5# each max if it's a single line, half that if it's a double. The stretch in a few inches of nylon line is almost zero with a 2.5# load.

Roy M 14-05-2016 10:13

Re: What is the best line to use attaching trampolines?
 
Zero stretch is my preference. When I walk on the bow net I want maximum stability. NOT a trampoline, rather a stable, comfortable and well draining extension of my deck.

mikereed100 14-05-2016 10:48

Re: What is the best line to use attaching trampolines?
 
I'm with Roy on this one. Our tramps are 9' square. When we had polyester net we used 3/16 polyester line to attach them and it was very inexpensive and gawdawful strong. I did not like the stretch and springiness though so we replaced them with Dyneema using 1/8" Dyneema for the lashings. Far more expensive but the tramps are far easier to walk on and a much more stable (i.e. safe) work surface now. They still have some give, more than I would like in fact, but we recently had 12 people on one net for a pot-luck photo op and the net didn't even sweat.


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