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07-22-2017, 10:34 AM
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#1
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Senior Member
City: Coastal SC
Vessel Model: Viking 65 CP MY (run at trawler speeds !)
Join Date: Jul 2015
Posts: 389
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What is the strongest 1" line for dock tie up ?
I ask as during hurricane Matthew, which was only category one with winds up to 60 mph, the boat got away as most of the 1" lines broke, and best I could tell not due to chafing...just flat out tension. No idea what the lines were exactly as they came with the boat... "soft " texture and black in color if that means anything.
So, what 1 inch line would be the least likely to break from stretch tension ?
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07-22-2017, 10:41 AM
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#2
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Guru
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,791
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Amsteel, but really need chafe protection.
__________________
Don't believe everything that you think.
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07-22-2017, 10:51 AM
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#3
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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I just use three braid nylon. I found out that the black lines seem to age out from UV exposure. Busted one pulling a stump with my truck, NO WAY was it anywhere near its limit. Nylon seems less susceptible to UV. Also like the stretch as that limits stress in the line.
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07-22-2017, 10:52 AM
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#4
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Valued Technical Contributor
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,775
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I seriously doubt if 1" nylon which is used for dock lines actually broke without first chafing. 1" has a minimum breaking strength of about 20,000 lbs. That will lift a lot of boats out of the water vertically. With four 1" lines on the corners of the boat, the piles or the cleats would give way first.
Chafe was probably the biggest factor.
David
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07-22-2017, 11:03 AM
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#5
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Guru
City: gulf coast
Join Date: Jun 2014
Posts: 3,440
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Really surprised they broke. Can you provide more info on where and how they broke? At a cleat? at a thimble? in the middle?
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07-22-2017, 11:17 AM
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#6
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Guru
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
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Quote:
Originally Posted by djmarchand
I seriously doubt if 1" nylon which is used for dock lines actually broke without first chafing. 1" has a minimum breaking strength of about 20,000 lbs. That will lift a lot of boats out of the water vertically. With four 1" lines on the corners of the boat, the piles or the cleats would give way first.
Chafe was probably the biggest factor.
David
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Agreed. Unless the lines were seriously degraded by age I would they would break just from the load.
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07-22-2017, 11:20 AM
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#7
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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In a storm, with a lot of boat motion the lines can really "snatch" violently. That's where a little stretch helps. The black ones have very little stretch.
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07-22-2017, 11:39 AM
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#8
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Senior Member
City: Coastal SC
Vessel Model: Viking 65 CP MY (run at trawler speeds !)
Join Date: Jul 2015
Posts: 389
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Quote:
Originally Posted by Ski in NC
In a storm, with a lot of boat motion the lines can really "snatch" violently. That's where a little stretch helps. The black ones have very little stretch.
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That must be it as they broke pretty much in the middle..I was amazed as well.....no chafing involved.....unless there was some previous chafe damage I didn't notice.
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07-22-2017, 12:23 PM
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#9
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Guru
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
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I am a fan of three strand nylon for permanent dock lines. They are strong, stretch, and easy to splice to the length you need. 3 strand is also relatively inexpensive so you can replace them easily after a few years if you see wear.
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07-22-2017, 12:40 PM
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#10
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Guru
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 12,818
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First, double up for storm lines. The first line should slow the boat as the line stretches, the second should stop the boat with only minor stretching. Repeated shock loading destroys a rope internally. In rock climbing, they use to (may still) rate ropes for number of falls. After so many falls (shock loads), the rope is retired.
Second, avoid short rope runs between dock and boat. The velocity at which the boat stops (a contradiction of terms), hugely impacts rope degradation. You want to slow the boat to a gradual stop, not jerk to an abrupt hault. Shock loading destroys the cords and can break loose boat hardware.
Ted
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07-22-2017, 01:20 PM
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#11
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Guru
City: Alexandria, VA
Vessel Model: 2000 Wellcraft
Join Date: Sep 2013
Posts: 1,467
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Quote:
Originally Posted by Xsbank
Amsteel, but really need chafe protection.
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Yes, with a breaking strength of around 100,000 pounds, one inch Amsteel is probably the winner by a lot!
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07-22-2017, 01:53 PM
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#12
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,119
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No stretch in amsteel....use it for chafe but beeter have someting for stretch.
Might as well use wire to tie thr boat up with.
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07-22-2017, 01:56 PM
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#13
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Guru
City: La Conner Wa.
Vessel Name: Sea Fever
Vessel Model: Defever 49 RPH
Join Date: Sep 2012
Posts: 877
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I am a big fan of Amsteel but would not use it for mooring lines as it has no stretch what so ever. Maybe use it as a back up to a nylon line, tied a little longer, so it doesn't come into play until the nylon is stretched out.
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07-22-2017, 02:04 PM
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#14
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Guru
City: Alexandria, VA
Vessel Model: 2000 Wellcraft
Join Date: Sep 2013
Posts: 1,467
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Quote:
Originally Posted by psneeld
No stretch in amsteel....use it for chafe but beeter have someting for stretch.
Might as well use wire to tie thr boat up with.
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Agreed.
But, it is the correct answer to the OP's question.
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07-22-2017, 02:09 PM
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#15
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,068
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Quote:
Originally Posted by Ski in NC
In a storm, with a lot of boat motion the lines can really "snatch" violently. That's where a little stretch helps. The black ones have very little stretch.
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Never heard color can affect stretch, before. The New England Ropes charts usually show that colors can matter (white and gold/white being "stronger" than other colors), but I don't remember anything about colors and stretch...
??
-Chris
__________________
Chesapeake Bay, USA
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07-22-2017, 02:44 PM
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#16
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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Quote:
Originally Posted by ranger42c
Never heard color can affect stretch, before. The New England Ropes charts usually show that colors can matter (white and gold/white being "stronger" than other colors), but I don't remember anything about colors and stretch...
??
-Chris
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I'm being very generic with the color. Not sure of a better description, but the super common black dock lines usually sold pre-made.
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07-22-2017, 03:00 PM
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#17
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Guru
City: Kitimat, North Coast BC
Vessel Name: Badger
Vessel Model: 30' Sundowner Tug
Join Date: Jul 2012
Posts: 5,946
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Quote:
Originally Posted by djmarchand
...1" has a minimum breaking strength of about 20,000 lbs...
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They test strength when dry. Wet nylon rope can lose up to 25% of its rated breaking strength...add in cyclic loading (which further weakens it) and a heaving boat...
__________________
"The most interesting path between two points is not a straight line" MurrayM
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07-22-2017, 03:04 PM
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#18
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,068
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Quote:
Originally Posted by Ski in NC
I'm being very generic with the color. Not sure of a better description, but the super common black dock lines usually sold pre-made.
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Ah, fair enough. We have some black 3/4" Samson double-braid lines and I don't they've ever stretched much. Stiff as a board, usually, even when new, even after washing, etc.
OTOH, the 5/8" black double braid NER lines have always been much more pliable, much easier to stretch as necessary...
Difference in thickness, of course... Both pre-made, though.... I'd guess maybe not so much the color but the brand, the way they're laid, etc...
-Chris
__________________
Chesapeake Bay, USA
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07-22-2017, 08:58 PM
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#19
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Guru
City: Punta Gorda, fl
Vessel Name: Escapade
Vessel Model: Nordic Tug 37 2002
Join Date: Jan 2015
Posts: 1,231
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8 Strand Plaited Nylon Line is one of the best for strength, shock and takes less space to store. Check out the picture. 100' of three strand on left and 100' of Plaited line on right.
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07-22-2017, 09:20 PM
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#20
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Guru
City: New England and Canada to Florida
Vessel Name: Tadhana
Vessel Model: Helmsman 38 Pilothouse
Join Date: Jul 2011
Posts: 596
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Well there have been some very interesting comments here about lines braking in the middle while under load. I have never see that and am interested to know if anyone can provide any more input as to how and why. 50+ years in boatyards and marinas i have seen a lot of dock lines fail in storms. But it was always at a chafe point. What am I missing? also amsteel has no stretch, zero, nada, and in rough conditions the entire shock load is directly applied to the points of attachment. A very strong rope, but might very well break the cleat at one end or the other.
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