Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 25-09-2020, 09:48   #1
Registered User
 
sanibel sailor's Avatar

Join Date: Feb 2013
Location: Ocala FL
Boat: 1979 Bristol 35.5 CB
Posts: 1,701
Dyneema topping lift failure

My Bristol 35.5 had a 1/8Ē stainless steel topping lift, fixed at the masthead and adjustable at the boom and when I bought her. The cable was deteriorated. I replaced it with a 1/8 inch dyneema line, same set up. This lasted about four or five years and then broke in the middle. I assumed it was too weak and had UV damage here in Florida. I replaced it with 3/16 inch dyneema, again single braid. Now four or five years later, this one has broken in the middle as well. Just sitting at the dock. It does not show any signs of chafe. I am considering going up in size and/or going with a covered dyneema line. Another alternative is a complete change of set up. I can rig an extra block for a topping lift at the masthead and bring it down to a cleat at the gooseneck. All my other lines are internal and run aft. Windage chafe and noise are disadvantages.
__________________
John Churchill Ocala, FL
NURDLE, 1979 Bristol 35.5 CB
Homeport currently Yankeetown FL
sanibel sailor is offline   Reply With Quote
Old 25-09-2020, 09:56   #2
Registered User

Join Date: Apr 2019
Posts: 968
Re: Dyneema topping lift failure

be interesting to see pictures - of where it broke.

Did you maintain it under significant load - cranked down? They do lose about 1/2 their strength within a year or two in that sort of UV. This UV strength loss happens even with braided covers - this has been proven in tests. You need a solid cover (like a plastic dip or heat shrink tubing) to get much uv protection on the core.

i'm surprised it broke in the middle (unless there was something was flicking it there). I guess it's possible that was sort sort of resonance/vibration point but a bit odd it would be same place for two different thickness.
Breaking Waves is offline   Reply With Quote
Old 25-09-2020, 10:20   #3
Registered User

Join Date: Mar 2011
Location: Southport CT
Boat: J/36
Posts: 1,380
Re: Dyneema topping lift failure

Makes you wonder how long the deteriorated wire would have lasted. Replacing the dyneema for the third time, is the cost coming up to what new wire would have been at the outset? We're tempted to switch our ss wire backstay and running backs to dyneema for the weight savings when we race, but so far (since 1981) they show no signs of needing replacement.
psk125 is offline   Reply With Quote
Old 25-09-2020, 10:24   #4
Registered User

Join Date: Apr 2019
Posts: 968
Re: Dyneema topping lift failure

we had dyneema check stays, same stays for 15 years. They were 10mm (bare), and they were not stored under significant load, but in use they were under significant load and did not break.

I test pulled one of them after 15 years and it was about 40% strength.

The UV resistance of bare dyneema differs significantly in its early years by brand. Some brands have more urathane coating on them, which provides some protection and others have almost none. After some years the difference between them declines as the coating wears off.
Breaking Waves is offline   Reply With Quote
Old 25-09-2020, 10:35   #5
Registered User

Join Date: May 2013
Location: Mangareva, French Polynesia
Boat: Heritage West Indies 36
Posts: 781
Re: Dyneema topping lift failure

Following. We have uncovered dyneema shrouds. Hoping to get ten years out of them.

I've had this sort of UV degradation with Spectra a few years back but not from dyneema yet. 3/16" does seem very light.

With regards to shrouds they say that when they get fuzzy it's a sign that they might be needing replacement soon. Presumably the fuzziness is caused by the outer layers breaking down in the sun but the inner layers should still be OK. Our shrouds are 11mm (7/16"). Does anyone know the penetration of UV into HDPE? At 3/16" it might penetrate right to the center, giving no signs of ageing before breaking. In that case going up a size or two would not only give you a greater percentage of strength to lose before it breaks but it might also slow the rate of UV degradation by protecting the inner layers better.

I'm just musing here, not suggesting anything in particular or claiming any great expertise on the topic!
DefinitelyMe is offline   Reply With Quote
Old 25-09-2020, 12:43   #6
Registered User
 
sanibel sailor's Avatar

Join Date: Feb 2013
Location: Ocala FL
Boat: 1979 Bristol 35.5 CB
Posts: 1,701
Re: Dyneema topping lift failure

Less sail chafe was a bigger driver to my decision than cost of stainless.

The upper splice is cowhitched over a Clevis pin and shielded inside the masthead assembly. It has retained its original color. Thimble lower end at the adjustment tackle. Break is about 15 feet above boom, length is 42 feet.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	236
Size:	380.1 KB
ID:	224182  
__________________
John Churchill Ocala, FL
NURDLE, 1979 Bristol 35.5 CB
Homeport currently Yankeetown FL
sanibel sailor is offline   Reply With Quote
Old 25-09-2020, 12:45   #7
Registered User
 
sanibel sailor's Avatar

Join Date: Feb 2013
Location: Ocala FL
Boat: 1979 Bristol 35.5 CB
Posts: 1,701
Re: Dyneema topping lift failure

Close up of breakage.
3/16" Breaking strength is reported at 5500 lb, almost double that of 1/8" (2900).
Should have been plenty without UV impact. I keep the mainsheet snug to prevent it from slatting when docked, but not cranked down.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	166
Size:	415.8 KB
ID:	224183  
__________________
John Churchill Ocala, FL
NURDLE, 1979 Bristol 35.5 CB
Homeport currently Yankeetown FL
sanibel sailor is offline   Reply With Quote
Old 25-09-2020, 13:03   #8
Writing Full-Time Since 2014
 
thinwater's Avatar

Cruisers Forum Supporter

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 7,534
Re: Dyneema topping lift failure

Quote:
Originally Posted by sanibel sailor View Post
Close up of breakage.
3/16" Breaking strength is reported at 5500 lb, almost double that of 1/8" (2900).
Should have been plenty without UV impact. I keep the mainsheet snug to prevent it from slatting when docked, but not cranked down.

Are you SURE these is not a sharp something or a fiberglass batten sticking out? More likely than any other reason.
__________________
Gear Testing--Engineering--Sailing
https://sail-delmarva.blogspot.com/
thinwater is offline   Reply With Quote
Old 25-09-2020, 13:07   #9
Registered User
 
Sailmonkey's Avatar

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 8,097
Re: Dyneema topping lift failure

Quote:
Originally Posted by sanibel sailor View Post
Close up of breakage.
3/16" Breaking strength is reported at 5500 lb, almost double that of 1/8" (2900).
Should have been plenty without UV impact. I keep the mainsheet snug to prevent it from slatting when docked, but not cranked down.


Our spectra topping had the exact same break at the 8 year mark!!

In fact, I still use the line for lashing odds and ends. Hereís a photo of one half of the break

Click image for larger version

Name:	IMG_1601064463.206024.jpg
Views:	133
Size:	415.8 KB
ID:	224184
Sailmonkey is offline   Reply With Quote
Old 25-09-2020, 13:12   #10
Registered User

Join Date: Apr 2019
Posts: 968
Re: Dyneema topping lift failure

hmmm . . .its always hard with pictures, but away from the break the rope does not look totally cooked - its not super fuzzy and the color looks decent. This should have taken around (very very roughly) 2500 lbs load to break in the middle, on its own with no 'outside influence'. That's a possible load if you really really cranked it piano string tight - but I would have guessed unlikily (for reference that would be like a full on upwind totally cranked genoa sheet loading).

It's not a 'clean cut', rather damaged/broken over an area. In the close up, on the right strand it looks like there are two further areas which have been 'bruised' down below the break.

There is nothing that could be flipping/hitting it there - like the tail of a wire tie on the back stay, or a batten end fitting on the sail?

There is discoloration like something with a little rust on it, or something applying extra heat there.

1/8" was too small (after taking into consideration uv over time) but the 3/16 should have been about right.

IDK, odd.
Breaking Waves is offline   Reply With Quote
Old 25-09-2020, 13:19   #11
Registered User

Join Date: Apr 2019
Posts: 968
Re: Dyneema topping lift failure

Quote:
Originally Posted by Sailmonkey View Post
Our spectra topping had the exact same break at the 8 year mark!!
This is a much cleaner break than the op's. Probably a different cause.

But what diameter is that? It looks quite big for a 32' boat topping lift.
Breaking Waves is offline   Reply With Quote
Old 25-09-2020, 13:27   #12
Registered User
 
Sailmonkey's Avatar

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 8,097
Re: Dyneema topping lift failure

Quote:
Originally Posted by Breaking Waves View Post
This is a much cleaner break than the op's. Probably a different cause.

But what diameter is that? It looks quite big for a 32' boat topping lift.


Itís oversized because I use t he boom and mainsheet to lift the dinghy alongside at night.

I want to say itís 1/4Ē but canít remember what Iíve bought to replace it. Also too lazy to go below and get the calipers to measure it.
Sailmonkey is offline   Reply With Quote
Old 25-09-2020, 13:38   #13
Registered User

Join Date: Apr 2019
Posts: 968
Re: Dyneema topping lift failure

That line is huge strength. Even after uv damage it did not break under topping lift or dinghy lift loads. And it is quite clean (except for the two distinctive last strands which finally gave under load). Something chafed/cut/heated it up in a quite narrow zone. I guess probably in a relatively short time frame or you would have noticed it.

I will comment in any case . . . . wire can chafe the leach of your mainsail, but it is rather less susceptible from breaking in this way. You just have to choose your poison.
Breaking Waves is offline   Reply With Quote
Old 25-09-2020, 13:54   #14
Registered User
 
sanibel sailor's Avatar

Join Date: Feb 2013
Location: Ocala FL
Boat: 1979 Bristol 35.5 CB
Posts: 1,701
Re: Dyneema topping lift failure

Original color was bright orange.
I keep the boom off center when docked, so unlikely to chafe on backstay. When sailing, TL is a bit slack. Battens insert at forward end of sail. Boat has not been underway in 6 weeks, on a dock in a narrow river without any waves and minimal wake. No weather of significance recently.
Same circumstances with my initial line. I just came to the slip one day and boom was in the cockpit.


I rather suspect low quality line with insufficient UV protection.


With what should I replace it? SS wire, covered high-tech stuff, better/bigger Dyneema?
__________________
John Churchill Ocala, FL
NURDLE, 1979 Bristol 35.5 CB
Homeport currently Yankeetown FL
sanibel sailor is offline   Reply With Quote
Old 25-09-2020, 14:03   #15
Registered User

Join Date: Apr 2019
Posts: 968
Re: Dyneema topping lift failure

If it were me, i'd go back to wire., since we don't know the cause of the failure. Something is going on with the 2 failures.

What was the brand of the line? I remember there was a samson amsteel 'knock off' which was super poor quality.
Breaking Waves is offline   Reply With Quote
Reply

Tags
dyneema, lift

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
how to install new outhaul and topping lift? deano Deck hardware: Rigging, Sails & Hoisting 4 01-01-2018 14:23
Boom Lift and Topping Lift skully Deck hardware: Rigging, Sails & Hoisting 1 19-05-2013 20:14
Rigging a Topping Lift off-the-grid Deck hardware: Rigging, Sails & Hoisting 17 16-03-2013 22:04
Lines From Leech To Topping Lift Moonchaser2304 Deck hardware: Rigging, Sails & Hoisting 12 12-04-2009 19:55
topping lift, boom vang and reef? scotty Deck hardware: Rigging, Sails & Hoisting 20 08-09-2008 21:12

Advertise Here


All times are GMT -7. The time now is 18:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.