Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-06-2016, 16:13   #1
Registered User

Join Date: Apr 2016
Posts: 177
new generation rope

What are possible applications of HMDPE eg Dyneemo. 10 mm breaking strength 11,000 # could be used as part of an anchor rode?
__________________

__________________
pdenton is offline   Reply With Quote
Old 13-06-2016, 16:22   #2
Registered User
 
salticrak's Avatar

Join Date: Jul 2011
Location: palmwoods qld australia
Boat: wharram tiki 26
Posts: 739
Re: new generation rope

I would not use it due to it's low stretch qualities.
__________________

__________________
salticrak is offline   Reply With Quote
Old 13-06-2016, 16:51   #3
Senior Cruiser

Cruisers Forum Supporter

Join Date: Feb 2012
Location: Carrabelle, Florida
Boat: Self-built 44' steel trawler
Posts: 873
Re: new generation rope

Agreed. Hell of a halyard or main sheet, but without the shock absorbing qualities of nylon or even chain.
__________________
tkeithlu is offline   Reply With Quote
Old 13-06-2016, 16:55   #4
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: new generation rope

A lot of fishing boat used to anchor in deep water with wire rope. Id be happy enough with spectra, as long as I had a stretchy snubber of some sort.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app
__________________
My Ramblings
Snowpetrel is offline   Reply With Quote
Old 13-06-2016, 17:19   #5
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: new generation rope

Quote:
Originally Posted by Snowpetrel View Post
A lot of fishing boat used to anchor in deep water with wire rope. Id be happy enough with spectra, as long as I had a stretchy snubber of some sort.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app
How would you attach a snubber to it? As it's so slippery that even the rope's own jacket slides around on it a good bit.

Also, I'm thinking that the only practical way to attach a snubber to it's core/bare Dyneema, would be to splice another short section of line into the rode, which would have an eye & thimble on the end of said short line.
So then, how do you decide where to install such pendants, & why in those locations? Plus, if said pendants ever happen to lay on the bed of the sea floor, I'd think that they'd present a big snagging risk.

Plus which, it's cost is on par with chain, if not higher. But without the advantages of chain. Including lifespan, ease of cleaning, & abrasion resistance. And a few more.
Also, given it's specific gravity, it's far more likely to fouls a prop, or wrap your keel, than all but a handfull of other line types (that are purpose designed to float.
__________________

The Uncommon Thing, The Hard Thing, The Important Thing (in Life): Making Promises to Yourself, And Keeping Them.
UNCIVILIZED is offline   Reply With Quote
Old 13-06-2016, 17:44   #6
Registered User
 
Delancey's Avatar

Join Date: Oct 2011
Location: Miami, FL
Boat: sunk by irma
Posts: 3,462
Re: new generation rope

Prolly could attach a snubber using one of these.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	137
Size:	370.2 KB
ID:	126115  
__________________
Delancey is offline   Reply With Quote
Old 13-06-2016, 17:46   #7
Registered User
 
Delancey's Avatar

Join Date: Oct 2011
Location: Miami, FL
Boat: sunk by irma
Posts: 3,462
Re: new generation rope

Inspired by a knotless connector intended for spectra fishing shown below. Works as advertised. No slip. Stupid simple.

Missing Link
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	133
Size:	248.2 KB
ID:	126116  
__________________
Delancey is offline   Reply With Quote
Old 13-06-2016, 18:05   #8
CF Adviser

Cruisers Forum Supporter

Join Date: Aug 2009
Boat: Custom Van De Stadt 47 Samoa
Posts: 3,743
Re: new generation rope

Quote:
Originally Posted by pdenton View Post
What are possible applications of HMDPE eg Dyneemo. 10 mm breaking strength 11,000 # could be used as part of an anchor rode?
French cruisers used a technique with polypropylene anchor line (which floats and is relatively low stretch like dyneema) in Polynesia - developed/designed to avoid snagging coral heads.

To add shock absorption what they did is tie one or several big fenders (usually big orange balls but it does not make any difference) to about the middle of the rode. This acts sort of like chain catenary but in reverse. The balls would be pulled down in gusts absorbing shock loading. It seemed to work but I never personally tried or tested it.

As to tying onto dyneema - I tested 4 different gripper hitches and the icicle was the best and will hold to a pretty high load - the hitch actually broke rather than slipping (12mm dyneema and 3/16 icicle). For a snubber you would need to play around with this - would need a stronger line for the icicle but larger diameter I believe holds less well - but that is a path I would pursue. I guess I would start by trying the same small diameter but in a multiple loop to get extra strength while still having the small diameter gripping.
__________________
estarzinger is offline   Reply With Quote
Old 13-06-2016, 18:30   #9
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: new generation rope

All valid points uncivilised, but there are also some big plusses to dyneema, its low stretch and abrasion resistance make it very chafe resistant. Its low weight can be a big advantage in some situations, such as rowing out a kedge.

The problems you mention can all be overcome with a bit of lateral thinking. The biggest issues are really cost, and it floating.

Its interesting that the dashews have gone to dyneema mooring lines, as have most ships and deepwater mooring systems.

Id like to have 100 meters of the stuff for my kedge anchor, where its lightweight and low stretch would be a big advantage. The floating would also help when rowing it out.

Id also use the length for shore lines, a drogue line, a very deep water extension for my normal chain, and a tow line. To give it some stretch Id copy the big shios and use a nylon tail at one end, eg for anchoring id go chain, then 10m of nylon, then the dyneema.

I would stow it on a reel to reduce the chance of tangles and splice big loops in either end. Maybe it would be worth splitting it into 2x50 meter lengths?
__________________
My Ramblings
Snowpetrel is offline   Reply With Quote
Old 13-06-2016, 20:52   #10
Registered User

Join Date: Apr 2016
Posts: 177
Re: new generation rope

I'm new to the forum and very impressed with the number of responses and all the different suggestions. MY feeling is that it is clearly a technological advance and I would like to integrate it. Chain is inelastic but has many advantages, but under high loads can snap i.e. fail suddenly. An all-chain rode is a consequence of the problem of winching a rope and chain. The most important reason for chain is to load the anchor horizontally with the line providing elasticity.
I'm out-fitting a boat I just bought, a Pearson 35, which has a small anchor locker. I have bought two shots 5/16 G4, 90' each. I have a Rocna 35 and supermax 35 mounted. A 45# Mantus in reserve. To match the chain i have 150' of double braid. So in such a small boat if I could somehow integrate a reel of spectra it would save weight and volume. A wet rope can weigh more than chain.
The catenary effect only counts at low loads, but is a plus. the idea of a float as a reverse catenary is interesting. Maybe a kellet could help.
Indeed the worst problem is fouling the prop.
PHD, PhD
__________________
pdenton is offline   Reply With Quote
Old 13-06-2016, 21:17   #11
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,326
Re: new generation rope

Quote:
Originally Posted by pdenton View Post
I'm new to the forum and very impressed with the number of responses and all the different suggestions. MY feeling is that it is clearly a technological advance and I would like to integrate it. Chain is inelastic but has many advantages, but under high loads can snap i.e. fail suddenly. An all-chain rode is a consequence of the problem of winching a rope and chain. The most important reason for chain is to load the anchor horizontally with the line providing elasticity.
I'm out-fitting a boat I just bought, a Pearson 35, which has a small anchor locker. I have bought two shots 5/16 G4, 90' each. I have a Rocna 35 and supermax 35 mounted. A 45# Mantus in reserve. To match the chain i have 150' of double braid. So in such a small boat if I could somehow integrate a reel of spectra it would save weight and volume. A wet rope can weigh more than chain.
The catenary effect only counts at low loads, but is a plus. the idea of a float as a reverse catenary is interesting. Maybe a kellet could help.
Indeed the worst problem is fouling the prop.
PHD, PhD
Personally, it would be simpler to go with 1/4" G70 and use a nice long nylon snubber (>30'). Much simpler. Truthfully, 1/4" G43 would be enough with a good snubber. That is the rig I use on a 34' cat. With a long snubber, the loads just are not that high.

Funny thing, in Sail this month they had a story where the wise sailor blames his snubber failure on age, when the real problem was that it was simply too short to absorb the energy--it takes length. He was in shallow water, so the chain catenary went bye-bye. Not going to learn much from that article.
__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Old 13-06-2016, 22:43   #12
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: new generation rope

Wow, these are some great ideas & insigthts on this topic. And it'll be interesting to find out how well some of them work. As it surely would be nice to replace a spool of high volume rope, like 3-strand nylon, with a svelte spool of Dyneema. Especially from a space onboard perspective, ditto on line weight.

I've always been curious about the use of Polypro rope for mooring & anchor lines, from the perspective of it's low UV resistance. Because aside from that, it would seem to have several plusses to it. Particularly in terms of when one needs to row out a shore line, or spare anchor.
__________________

The Uncommon Thing, The Hard Thing, The Important Thing (in Life): Making Promises to Yourself, And Keeping Them.
UNCIVILIZED is offline   Reply With Quote
Old 13-06-2016, 22:59   #13
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: new generation rope

I agree that its hard to beat all chain for a primary anchor system. I see future applications where dyneema rode might be preferable to a nylon rode for a secondary system, or exceptionally deep water anchoring. Especially given the potential issues with nylon chafing and heating up at high loads. Cost is the biggest real issue, and given the amount you can downsize due to the extra strength the real extra cost may not be that much more than nylon brait rope of equivalent strength.

Looks like there are plenty of options to add a nylon snubber and that float/drag trick really does work exceptionally well to damp peak loads and yawing, without the bounce associated with a long nylon snubber, kind of like a cars shock absorber.
__________________
My Ramblings
Snowpetrel is offline   Reply With Quote
Old 14-06-2016, 01:37   #14
Registered User

Join Date: Apr 2007
Location: Australia
Boat: Island Packet 40
Posts: 1,373
Images: 7
Re: new generation rope

Quote:
Originally Posted by thinwater View Post
Personally, it would be simpler to go with 1/4" G70 and use a nice long nylon snubber (>30'). Much simpler. Truthfully, 1/4" G43 would be enough with a good snubber. That is the rig I use on a 34' cat. With a long snubber, the loads just are not that high.

Funny thing, in Sail this month they had a story where the wise sailor blames his snubber failure on age, when the real problem was that it was simply too short to absorb the energy--it takes length. He was in shallow water, so the chain catenary went bye-bye. Not going to learn much from that article.
A trick I have used with a nylon snubber on a chain mooring system in shallow water was to run it over the bow chain roller back along the deck and cleated it off on an aft cleat.

I think that because it is stretchier nylon has the highest energy absorption capacity when used as a snubber but poly tends to float and not snag on things by dragging about on the bottom when used for anchoring.
__________________
RaymondR is offline   Reply With Quote
Old 14-06-2016, 01:58   #15
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,735
Re: new generation rope

Quote:
Originally Posted by Snowpetrel View Post
I agree that its hard to beat all chain for a primary anchor system. I see future applications where dyneema rode might be preferable to a nylon rode for a secondary system, or exceptionally deep water anchoring. Especially given the potential issues with nylon chafing and heating up at high loads. Cost is the biggest real issue, and given the amount you can downsize due to the extra strength the real extra cost may not be that much more than nylon brait rope of equivalent strength.

Looks like there are plenty of options to add a nylon snubber and that float/drag trick really does work exceptionally well to damp peak loads and yawing, without the bounce associated with a long nylon snubber, kind of like a cars shock absorber.
I think single braid dyneema could be quite all right as the secondary part of a mixed rode, after a goodly length of chain. Compared strength to strength, it is not actually more expensive than other materials, or not much more. It has far superior chafe resistance. Being slippery and hard, it will be far easier to chafe-proof, and it won't suffer from internal heating or the other problems of normal rope. I don't think you care so much about shock absorption if you have 100 meters or 60 meters or whatever of heavy chain ahead of it, especially if you have a decent way to attach a snubber.

I think it's a promising idea.
__________________

__________________
"Parce que je suis heureux en mer, et peut-Ítre pour sauver mon ame. . . "
Dockhead is online now   Reply With Quote
Reply

Tags
rope

Thread Tools
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
Question aboud Rope and rope thimbles jaaaaay Off Topic Forum 16 23-04-2016 11:07
Rope to rope 'snubber' mjcayman Anchoring & Mooring 5 12-07-2014 08:11
Rope on rope chafe ScuzzMonkey Anchoring & Mooring 27 29-11-2013 17:44
For Sale or Trade: Lewmar Superlock D2 rope clutch for 3/8"-7/16" rope, $70 chienbizarre Classifieds Archive 0 14-10-2012 17:28
NEW GENERATION Anchor by Subaru cat man do Anchoring & Mooring 1 30-06-2011 04:27



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 16:11.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.