10mm or 3/8" - how critical for Lewmar D2?

[steve77]

I have two problems that I want to remedy. First, our main halyard (1/2 inch New England Ropes Sta-Set double braid) is very tight going through the rope clutch - A Lewmar D2 10-12mm. There is enough friction at the clutch to make it difficult to properly tension the mainsail. Secondly, after several hours of sailing the main halyard has enough stretch to result in poor sail shape.

I would like to replace the main halyard with something that would fit the rope clutch and also have less stretch. I was looking at New England Ropes Endura Braid. This line has a dyneema core with a braided polyester cover.

My concern is that the New England Ropes website states that this line is available in 3/8 inch-10mm as if these two numbers are identical. To save you the math, 3/8 inch is 9.52mm. Since the Lewmar D2 rope clutch is sized for 10-12mm line, I want to make sure that it will properly grip the Endura Braid.

Anyone have any experience with this? Is the Endura Braid actually 10mm or is it 3/8 inch? If it is 3/8 inch, will the rope clutch grip it even though it is slightly smaller than the size line that it is designed for?

Note - I have sent e-mails to both New England Ropes and Lewmar and have not received any replies.

Thanks!

Steve

[PaulinOz]

OR

10mm = 25/64 inch

[Training Wheels]

I have used both Warpspeed and Endura braid in my D2's. In my experience, Warpspeed is 3/8ths and Endura braid is slightly larger, 10mm. The Endura Braid has a bit more friction through the clutch, but I would suspect more holding power. I have been switching my lines over to Endura Braid.
If your clutch is a 12, then to get the max holding power you'd have to go with 12mm line. For 10mm line, if holding power is a concern, then you'd want to go with a 10. I do have some control lines that are 5/16", in a 10 clutch that hold fine, but the loads aren't that high.
I believe Lewmar used to have a chart showing the estimated holding power of different size lines in their clutches, it's probably available on their website.

[Stumble]

It will work fine, but there are a few tricks to getting the best out of the clutches.

1) cycle the clutch before taking the load off the winch, or just open them before you pull the line in. This cuts slippage by about half.

2) slowly release the load from the winch.

3) if you still see a slippage issue you can bury a piece of thin dyneema in the core of the endurabraid. You just herniated the core out of the cover, burry a thin (say 1mm or so) piece of dyneema, About 6" for and aft of where it hits the clutch. This will bulk the line a decent amount and reduce slippage.

Finally endurabraid has a very good reputation of not slipping in clutches. The cover is tight and bound to the core well. Which means there is a lot of preassure against the cam. Very loose weave line like NER Salsa for instance slips quite a lot, since the loose weave has a lot of room to crush down.

[steve77]

Thanks, all. I appreciate the input!

Steve

[roverhi]

No personal experience with Lewmar Clutches, only Spinlock, but 3/8" line has worked fine in them. Also in the climbing hardware of my ATN climbing gear even though they say to use larger diameter line than 3/8".

Can't imagine that the difference in diameter of 10mm and 3/8" line would have any effect. Switched between mm and inch diameter wire in Norseman terminals doing rigging without issue.

[UNCIVILIZED]

Another option for adding a bit of grip to 10mm line in 12mm clutches is to add some extra cover where the line will get gripped by it. Which can also have the perk of increasing wear resistance, in that primarily the wear will occur on the extra jacket, & not on the primary line itself. Look up some of the rigging, splicing, & cordage options at places like www.APSltd.com or similar. And if you need more info sources, or cordage suppliers, let us know. As there are LOTS of options that you can go with in terms of materials, splicing, & hardware. Far more than have been mentioned here.

Also, if it's not obvious, the best way to maximize grip in a line clutch is to use the biggest line that will fit into it. As holding power in them drops precipitously as line diameter goes down in relation to what'll fit in them. With 10mm taking a huge hit as compared to 12mm.

You also would be well served to look at the line application guides at places such as the Sampson Ropes website, & to consult the product guides too. As they show the stretch characteristics (at various load ratios) of the various cordages.

Samson's Warpspeed is pretty much the benchmark that most lines are compared to. With great stretch characteristics, light weight, & outstanding longevity. Albeit in your case another option would be to use the jacket from your current halyards over the properly sized high modulus core.

[onavegador]

My sailmaker warned me in 2002 when I told him that I would install some Lewmar rope clutches on my catamaran. Maybe that Lewmar has worked since on the design of their rope clutches.
I was searching then for more advice and finally I decided to install Spinlock rope clutches for the halyards, topping lift, sheets, traveller and accidential gybe preventer.

I have to say that on the boom I had already Lemar rope clutches installed by the previous owner for the 3 reefing lines. So far they worked well but the ropes had 12mm diameter, a little bit less than 1/2".

I would propose you to try with a sample of 1/2" diameter rope through the rope clutch and engaged on a winch. When stretching the rope you will probably see if it slips through or not. Try the rope dry and wet.

Good luck.

[Dave22q]

The odds on this tiny difference mattering are slim to none. Sailing is not rocket science. Very little on any boat was made with such fine tolerances. A 64-th of an inch is no big deal.

[UNCIVILIZED]

Originally Posted by Dave22q

The odds on this tiny difference mattering are slim to none. Sailing is not rocket science. Very little on any boat was made with such fine tolerances. A 64-th of an inch is no big deal.

The above is entirely true. As 2 lines of the "same size" can vary by 1/8" from one manufacturer to the next, & even significantly in measured diameter from one line type to another from the same manufacturer.

For example, the first time I bought a spool of Amsteel Blue, it's measured diameter was almost 3mm larger than it's nominal size. And I was ready to send a few samples of it out for testing until I spent 15min talking to Sampson. Where they gave me the scoop, but still said they were more than happy to test it for me if I so wished.

Plus, some lines lose more of their diameter than others once they've been fully loaded up a few times.

[dfelsent]

Clutches are great. They all slip at some point. But they are still great to have.
I make sure that I open and close the clutch before taking the load off the winch. That helps minimize slip. If I can, I cleat the tail. If I care about slip and can't cleat the tail i take a bight of the tail and make a half hitch around the loaded part of the line forward of the clutch. That stops slip in its tracks.
I also (sometimes) put the load back on a winch prior to opening a clutch. Much less wear on the line's cover and on the clutch. Also easier to open the clutch.
I have worn clutch jaws when I have not done this.
A clutch is a wonderful piece of hardware. But not a perfect thing.