Thursday, 22 July 2010

On the Ropes.

The ropes or lines on Rosie are in reasonable condition, (rope, is also called a line or warp when used aboard a boat) however, I am tempted to purchase some longer replacements. We want to spend some time cruising the river network which will require Rosie to have longer lines available. I also want to be able to configure the boat to enable single handed trips if needed. Longer lines will make the tying up in locks much easier single handed.

I did look at one or two items of rope that were on offer whilst walking around the boat show at Crick. But  did not make a purchase. In the main because I was not sure which of what was available would be useful to me. I was not knowledgeable enough about the charateristics of lines. I figured it was time to go looking on that font of all knowledge "Google" on the tinterwebbie!

This is not a masterclass on ropes, lines or warps it is just a collection of notes taken from my research reading so far. For instance, it would seem that a rope or line is classified by whether it is made of natural or synthetic fibre, it's physical construction (including the number of ply) and diameter and breaking strain.

Rope can be further sub-divided into two groups – laid and braided. Laid or three-stranded ropes are most common on leisure boats. Braided ropes have a core at the centre that carries the load. The rope has an outer braided cover or sheath to protect the core and make the rope easier to grip.

I shall concentrate my google research on laid rope rather than braided.

Main Synthetic Rope Types.

Also known as Terylene or Dacron. Polyester is the stuff from which most boating rope is made of. It is resistant to rot and ultra-violet light, it also sinks in water. 3-strand polyester rope is a rope used mainly for mooring and anchoring. Even when wet polyester retains full strength and remains easy to handle. Polyester stretches very little and is excellent in resistance to abrasion. It is easy to splice and can be used for lanyards, fenders and fender lines.

Has more stretch than polyester. Polypropylene floats in water and will over time degrade under ultra-violet light. 3-strand Polypropylene rope is the most versatile rope that's manufactured. Polypropylene rope is strong and great value for money. It is a good all round rope that can be used for a variety of tasks.

Dyneema lines have the highest strength to weight ratio. Polyethylene lines don't hold knots well. Dyneema is a synthetic fibre based on ultra high molecular weight polyethylene, 15 times stronger than steel and up to 40% stronger than Kevlar.

Nylon is very stretchy and used for anchor ropes and towing lines. Its stretchiness makes it very good at storing energy. Then if it breaks, all that stored energy is released extremely quickly. This can cause serious whiplash types of injury.

Synthetic Polyhemp.
Polyhemp or Hempex Rope is a 3-strand synthetic rope made to look like a natural fibre rope. This soft handling rope is easy to grip and is soft on the hands. It has excellent breaking load, good resistance to abrasion and will not rot. It has low stretch and is easy to splice.

Pros of synthetic line: very strong, has excellent resistance to rot, mildew and deterioration, and it is extremely resistant to harmful sunlight U.V. rays and weathering. Another pro of synthetic line is its elasticity in applications where that is an important factor.

Cons of synthetic line: slips much easier than natural line so it is not ideal for knots and for use with deck fittings, its elasticity can be dangerous if it parts during a load bearing operation such as towing, and it is susceptible to chafing from rough surfaces.

Main Natural Fibre Rope Types.

Real Hemp Manila.

Hemp, Manila, Sisal and Cotton are all natural fibre rope. Little of this type of rope is made now, and for that reason  it is quite expensive. Because it is a natural fibre rope manila will shrink when wet and lengthen when dry.
Cons of natural fibre line: Poor performance in load bearing applications such as towing, it is not resistant to rot, mildew and deterioration, and it has poor resistance to chemicals compared to some synthetic ropes such as polypropylene and polyethylene.

Pros of natural line: Strong (but not as strong as synthetic), resistant to harmful sunlight UV rays and weathering, and it is resistant to abrasive surfaces.
Common Rope Diameter.
6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm and 24mm
The Breaking Strain of a rope or line will vary with the material used as well as the construction of the rope. Remember that over time the rope will also weaken through everyday usage.

Tips I picked up along the way.
  • Rope now comes in different colours, so by using different colours you could help to identify different rope lengths for instance.
  • The rope must be much weaker than the weakest fixing point on your boat. That certainly applies to any towing points or anchor points if these ever come under any significant strain.
  • The correct way to clean a length of rope is to put the rope in a pillow case with the end tied, and then place the pillow case in the washing machine.
  • Natural fibre line should be uncoiled from the inside of a new coil in order to prevent kinks.
  • It is possible to reduce the wear and tear on a rope by use of clear soft plastic pipe which can be slid along the rope to the point of abrasion. Some people also use bicycle inner tubes for the same purpose.
  • There is no such thing as an old or disused rope. Old rope can be used for internal stuffing on buttons and fenders. So there is money to be saved for old rope.
  • Forward mooring ropes should when required be tied off to a length not long enough to reach the propeller if they should fall into the water.
  • Floating rope such as Polypropylene can be used to help keep longer ropes away from the propeller if they should go into the water.
  • Keep a short length of rope (six feet should do) on the stern dolly with a large foot sized loop and a spaced series of large knots as hand holds. This can be used to help you climb back onboard if you should accidentally slip over the side into the canal. You need to be able to reach the rope from the water.

Some Rope Suppliers.

Sharp and Enright
Trafalgar Marine
English Braids
Cheap Ropes
Rope Locker

Want to tie a knot?


1 comment:

  1. Nice post to come across different types ropes as well as their uses. Now a days rope manufacturers are increasing at a faster rate, if you are looking for ropes which are made using high technology and from a technical know how people then you can get it from Axiom Cordages Limited. It is one of the leading manufacturer and supplier of all types of Ropes.


Please put your name to your comment. Comments without a name may automatically be treated as spam and might not be included.

If you do not wish your comment to be published say so in your comment. If you have a tip or sensitive information you’d prefer to share anonymously, you may do so. I will delete the comment after reading.