Dynema for winching boat

[adamgweba]

we have a butt cat, +_ 2.5t. we have a T max 9000 winch currently with steel cable, a warn 9000 also steel cable and a spare come up, also steel. they are mounted 1 on a tractor, 1 on a trailerr, and then a spare, as the boat is too big to hand winch so if a failure, we need to be able to make a plan.

I am considering putting dynema on the winches, for safety, as well as ease of use, and the steel is prone to rust so hence the dynema.

What dia/ strength dynema should i get? And what sort of length can i fit on the winch?
I guess with the dynema it is NB to ensure there is no chafe happening over a sharp point on the trailer that could lead to damage to the rope.
what is the set up with the dynema to the hook?

[BruceHun]

I have this on my Rhino 9500lb, 25m standard on the winch. Been running it for coming up to 4 years and used a lot on the beach. No issues. Same hook as the steel winch. Attachment looks like this.

[Spiceman]

One will often find that Dyneema is extremely abrasive resistant. Often more than steel. Obviously should there not be sharp edges where its used. An interesting thing is the difference between the roller style fairlead for steel cable and the aluminium hawse fairlead for synthetic rope.

[clivemd]

11mm x 28m what I use on my winch

[Henkus]

So you have a 9000lb winch, just over 4000kg in working strength of the first layer on the drum. 11mm rope is way north of 10000kg break strength. Your winch will fail, overheat, battery might die way before anything happens with the rope/cable.

Anything bigger than 8mm rope on such a small winch is overkill. 8mm is 6800kg MBS. Bigger diameter means less rope on the drum.

I see more boats being trailered with steel wire rope than dyneema. I also see more dyneema ropes breaking while boats are being loaded. Only steel cable I have seen break was the 6mm that was on a handwinch.

[Henkus]

And just for interest sake, this rope was used for retrieving a ski boat only. It failed as the heat radiating from the brake on the drum went beyond the melting point of plastic. Remember, dyneema is just a fancy name for plastic that went to Michael House and not a model C school.

[adamgweba]

Thanks Henk, so you are saying rather stick to the cable.

Maybe a decent set of leather gloves for working the cable.
The stuff is expensive, and if it wont last, stick tot he known materials. weight isnt our problem at all as the boat is only towed 1.5km.

[Peter Connan]

I read on this forum that the usable load of snatch straps reduce significantly if they are wet (I think 50%). I wonder if the same is true for Dyneema, and if that might be the cause for many of the reported breakages?

Also I suspect that winches run for much longer periods when hauling out boats than they do in most 4x4 recovery situations?

[dirtshark]

I have had 11mm Dynema on my boat winch for 10 years, its an overkill I know but I will never go back to a steel cable. Many years ago a mate of mine imported some of the first rolls of Dynema into SA for use in the fishing industry and I had 4mm Dynema on my hand winch for my 14'6" Ski Vee.....guys on the beach couldn't believe it

[Spiceman]

I read on this forum that the usable load of snatch straps reduce significantly if they are wet (I think 50%). I wonder if the same is true for Dyneema, and if that might be the cause for many of the reported breakages?

Also I suspect that winches run for much longer periods when hauling out boats than they do in most 4x4 recovery situations?

One problem that I saw (on yootube) wrt dyneema ropes on winches, is that since the cable/rope isn't guided during a recovery, such rope doesn't lay neatly next to each other. Also, thension on the rope is not the same for every revolution and layer. Wire rope (steel cable) has more of a tendency to lay neatly next to each revolution and layer. So the dyneema bundles up and sometimes gets pulled extremely tight over and into previous layers and that cause failure of the dyneema rope.

[Spiceman]

I have had 11mm Dynema on my boat winch for 10 years, its an overkill I know but I will never go back to a steel cable. Many years ago a mate of mine imported some of the first rolls of Dynema into SA for use in the fishing industry and I had 4mm Dynema on my hand winch for my 14'6" Ski Vee.....guys on the beach couldn't believe it

I read on the net that dyneema rope don't last as long being outside in the elements (sun) on a spool/winch. Whats your opinion?

[clivemd]

And just for interest sake, this rope was used for retrieving a ski boat only. It failed as the heat radiating from the brake on the drum went beyond the melting point of plastic. Remember, dyneema is just a fancy name for plastic that went to Michael House and not a model C school.

the Dyneema that I got from the UK is totally different from what I seen in SA
there might be a difference in Dyneema and synthetic rope that is sold in SA as so called Dyneema

[clivemd]

I read on the net that dyneema rope don't last as long being outside in the elements (sun) on a spool/winch. Whats your opinion?

It is UV treated but like anything sunlight will brake it down over time, when not in use needs to be covered, if I don’t use my winch for long times I remove my Dyneema and store inside, when on winch I made a ally cover to protect from sunlight

11mm Blue Dyneema® Winch Rope comes ready rigged with a hook and thimble and can be made with a terminal or tapered end as required.

• Rated at 12.6T, (27,720lbs) this rope is ideal for 9,000, 9,500 and 12,000lb winches.
• An immensely strong 12 strand synthetic winch rope made from Dyneema® SK78 High Modulus Polyethylene Fibre.
• This creates an incredibly robust, strong and lightweight safer alternative to wire rope.
  
• After manufacturing the 12 strand rope, it is heat set under tension to ensure durability, uniformity and maximum strength.
  
• Very light easy to handle very strong.
  
• Easily spliced does not kink or curl up like wire rope.
  
• It floats.
  
• Less effort in use does not kink or curl, safety in use.
  
• No more wire rope ‘spikes’ to catch in the gloves.
  
• A lot lighter and safer than a wire rope.
  
• Ideal for extension winch ropes as well.
  
• If it did break, like any wire rope could do in a ridiculous Scenario, Dyneema® Bowrope will not flail. A very important safety feature.
  
• UV stabilised giving the rope a long and safe working life.
  
• Very durable due to its good resistance to both mechanical and environmental attack.
  
• Another reason to use Dyneema® Bowrope is that it stretches very little, even under full load.
  
• Dyneema® is a registered trademark of ROYAL DSM N. V. and is produced in accordance with ISO 2307:2019

[Rainier Vermaak]

the boat is only towed 1.5km.

That is a long winch...

[JanB]

Speak to the guys at Southernropes. They are in your valley and supply to the marine and rigging industries. They should be able to provide you with good advice.

Remember that Dyneema is just one brand of Ultra-high-molecular-weight polyethylene (UHMWPE). There are specific ropes for specific applications with all sorts of different weaves, sheathing, strand thickness etc.

From my experience with using it on a sailing dinghy (i.e. not winching):

• Soft and pleasant to work with. You don't have heavy, hard coils that want to whip you in the face or take your head off when they snap.
• 5-15 times stronger than steel for the same diameter.
• Light and it floats.
• It is more susceptible to UV degradation than steel, but then it does not rust on the inside where you cannot see the damage. (For example, for standing rigging on yachts - the lines that hold the mast up - it is recommended to replace steel shrouds every ten years because corrosion cannot be measured or observed. Rope degrades from the outside, so you replace when it starts to look weak.)
• Rope does stretch. That should not matter when winching.
• You can splice (put in eyes, loops and thimbles) yourself with very basic tools. No special pliers and crimping tools necessary. That alone makes it cheaper than steel, even if the cost per length is slightly higher.

So, UHMWPE is not the perfect solution for all applications, but I would explore the options carefully before using steel.

Edit: I typed slower than Clivemd.

[dirtshark]

I read on the net that dyneema rope don't last as long being outside in the elements (sun) on a spool/winch. Whats your opinion?

The sun stuffs everything up so mine is covered with a canvas bag.....I find the biggest problem with the smaller diameters is that it cuts/binds in when layering, that's why I went with the 11mm.