Reefing - new setup - dyneema size

[Tintin]

Ok, the questions continue (sorry if covered on other threads - phone and forum search function make it hard to search).

New to me benny first 325 has reefing lines from leech cringle into boom, to gooseneck, with a handy small winch and in-boom jammer.

As part of refit, and as i will be rebedding deck hardware (removing headlining today revealed numerous leaks), I am thinking of changing reefing so it is easier to do in cockpit, and going with 1st and 2nd reefs using balance block in boom, with third reef done with seperate leech and luff lines.

All lines led back to cockpit (i know, new organisers and clutches but am keeping this boat for a while).

I have read about people changing to thinner dyneema to reduce friction - 8mm seems about right but do you think I could use 6mm?

I know handling will be harder but the reduction in friction, cost, and cordage in cockpit would all be a bonus.

Thoughts?

 

[sailorman]

you need wear redundancy i have 12m/m braid on braid on a 37 footer it has done 15 yrs to date

 

[Pinnacle]

I suspect this issue for you with new dyneema lines is not going to be "are they strong enough" but "are they a size I (and the winches ) can comfortably handle". I know it will cost more, but thicker lines will be much easier to handle.

 

[Javelin]

On a reefing line you only need dyneema on the section you don't handle and that can be 4mm.
On the rest braid on braid is fine - Minimum 8mm, nice is 10mm and luxury is 12mm.

As said above the only reason for using dyneema is that it allows you to reduce dia but keep strength.
4mm dyneema has a break of at least 1200kg (depending on make) more than enough for a reef line.

I personally don't like big thick ropes dangling from my leech so I use 4mm tapered to 8mm for the cockpit end.
With my sensible cruising hat on I'd use 10mm throughout for a 32 footer.

 

[lw395]

Might there be an issue with the low stretch of dyneema?
Could those lines be put under great tension for instance by the boom moving?

 

[Javelin]

If in the unlikely event that you pulled down the reef so tight to the boom that there was no play left then I guess it could be and issue but the issue would be a block letting go more than a rope issue.
It also depends on the route your lines take, I not sure on mine the angle of the boom would make any difference.

However in practice I doubt you would ever get the reef that tight unless you had a gorilla on the reefing winch or worse you used an electric one.

 

[bitbaltic]

We have just changed out all our reefing lines on a big-rig 30 footer to 6mm Dyneema throughout, no problems on hands or winches as the setup is very low friction. You will not exceed the breaking strain of 6mm.

However, we have done many other things to reduce friction e.g. fit a teflon mainsail track and carefully set up our lines led back, so it is not just about going down a line size as the only solution.

the balance block is not about reducing friction, it is about increasing purchase. It is probably cheaper to fit one than to tackle friction say in your luff groove by fitting an expensive track. However, if you first tackle friction wherever you find it, you will not need to resort to things like that on a 33 footer, and you will be able to keep it slick and simple. I'm not saying that you shouldn't fit one- they are generally reliable and inexpensive- but they are about tackling the problem form the other end with respect to changing out your lines IMHO.

Cheers

 

[srah1953]

If you are going to change everything then size the clutches for the thickness of rope you propose to use. I have XTS 0814 clutches and I thought that I would change to 8mm dyneema, but it was suggested to me that there would be potentially greater slippage in the clutch with 8mm rather than 12-14mm. I don't know if it's true but worth bearing in mind.

 

[vyv_cox]

the balance block is not about reducing friction, it is about increasing purchase. It is probably cheaper to fit one than to tackle friction say in your luff groove by fitting an expensive track. However, if you first tackle friction wherever you find it, you will not need to resort to things like that on a 33 footer, and you will be able to keep it slick and simple. I'm not saying that you shouldn't fit one- they are generally reliable and inexpensive- but they are about tackling the problem form the other end with respect to changing out your lines IMHO.

Cheers

Some confusion about the function of a balance block? Its purpose has little to do with purchase, it is there to allow reefing with a single line instead of separate ones for tack and clew.

I use 10 mm Dyneema, mainly because smaller sizes would probably not be accepted by my existing clutches and ST winches. I suspect that 8 mm may well work but at the time I bought mine, quite a few years ago, I thought it best not to risk it with me and boat 2000 miles apart.

 

[bitbaltic]

Some confusion about the function of a balance block? Its purpose has little to do with purchase, it is there to allow reefing with a single line instead of separate ones for tack and clew.

I use 10 mm Dyneema, mainly because smaller sizes would probably not be accepted by my existing clutches and ST winches. I suspect that 8 mm may well work but at the time I bought mine, quite a few years ago, I thought it best not to risk it with me and boat 2000 miles apart.

OK. I thought the OP was referring to an arrangerment of blocks to increase purchase in the boom, my mistake.

 

[Tintin]

OK. I thought the OP was referring to an arrangerment of blocks to increase purchase in the boom, my mistake.

regarding leads and clutches, the old XA's and Francespa4 clutches are being replaced with XAS. I considered XTS but the XAS have a wider rope size range and a I think the loads will be fine. I am going with new deck organisers, replacing the old Lewmar 3 sheaves with stacked spinlock T50 3 sheaves, and replacing some of the mast base blocks. This will reduce friction.

The main reason for 8mm or smaller is to reduce bulk and cordage in the cockpit area. I must check the winch tailors are ok with 8mm and maybe 6mm, although my old boat had neither tailers or clutches so i am sanguine about the tailers.

Another thought this morning was instead to mount a halyard winch for the main at the mast and avoid the cost of all these changes, this reducing the trips back and forth to the cockpit.

 

[Daydream believer]

Some confusion about the function of a balance block? Its purpose has little to do with purchase, it is there to allow reefing with a single line instead of separate ones for tack and clew.

Personal preference but I would not bother with blocks in the boom for single line reefing on a boat OP's size. Not necessary increased cost & friction & just another problem if something fails.
On my Hanse 311 - which has a relatively big main for boat size- i have 8 mm braid on braid reef lines.
I found thicker lines create more friction
Dynema tends to slip slightly more in spinlock clutches - I found this changing my halliards from braid on braid to dynema

 

[prv]

On a reefing line you only need dyneema on the section you don't handle and that can be 4mm.
On the rest braid on braid is fine - Minimum 8mm, nice is 10mm and luxury is 12mm.

That sounds brilliant - slippery skinny 4mm dyneema up around the sail where you don't touch it, and nice fat 10mm polyester where you do. But what kind of splice would I use to taper from from one to the other? I can do braid eyes (with a reminder of the different length markings) but have never really handled dyneema before.

Pete

 

[JohnGC]

with third reef done with seperate leech and luff lines.

Since one of your aims is to reduce cockpit line clutter. Have you considered not having the 3rd reef luff line running back to the cockpit? On my 32 footer I'm happy going to the mast to put in the 3rd reef and have a permanent 3rd reef leech line. Reefs 1 & 2 are single line.

That sounds brilliant - slippery skinny 4mm dyneema up around the sail where you don't touch it, and nice fat 10mm polyester where you do. But what kind of splice would I use to taper from from one to the other?

I'm also very interested in that.

 

[vyv_cox]

Personal preference but I would not bother with blocks in the boom for single line reefing on a boat OP's size. Not necessary increased cost & friction & just another problem if something fails.
On my Hanse 311 - which has a relatively big main for boat size- i have 8 mm braid on braid reef lines.
I found thicker lines create more friction
Dynema tends to slip slightly more in spinlock clutches - I found this changing my halliards from braid on braid to dynema

I originally installed single line with balance blocks on a 29 ft boat and have had them for 20 years on a 34. Not really sure why the size of boat has much to do with it, over about 20 ft. It's about simplicity of reefing and reducing the length of lines in the cockpit.

 

[Daydream believer]

I originally installed single line with balance blocks on a 29 ft boat and have had them for 20 years on a 34. Not really sure why the size of boat has much to do with it, over about 20 ft. It's about simplicity of reefing and reducing the length of lines in the cockpit.

But you have to buy more rope to start with because you effectively have a double line in the boom.
As for reducing the line in the cockpit- I will have to think about that as I am not sure you are correct- But then you may be. I would be tempted to rig a simple jig up to check

is he correct?? anybody!!!!!

 

[vyv_cox]

But you have to buy more rope to start with because you effectively have a double line in the boom.
As for reducing the line in the cockpit- I will have to think about that as I am not sure you are correct- But then you may be. I would be tempted to rig a simple jig up to check

is he correct?? anybody!!!!!

Assuming you are taking reefs back to the cockpit, then you have a tack line that probably is 1:1 and a clew line that is 1:2 plus the length of the boom, both plus the distance from the boom through blocks and organisers to the cockpit. With a single line using balance blocks you have all that minus one line from boom back to cockpit. The main point is that you only haul in one line and if set up properly it is almost automatic.

There is a drawing of my arrangement at http://coxengineering.sharepoint.com/Pages/Singlelinereefing.aspx

 

[Daydream believer]

Assuming you are taking reefs back to the cockpit, then you have a tack line that probably is 1:1 and a clew line that is 1:2 plus the length of the boom, both plus the distance from the boom through blocks and organisers to the cockpit. With a single line using balance blocks you have all that minus one line from boom back to cockpit. The main point is that you only haul in one line and if set up properly it is almost automatic.

There is a drawing of my arrangement at http://coxengineering.sharepoint.com/Pages/Singlelinereefing.aspx

So you get the same amount of line in the cockpit, You need more line to set it up, you create friction inside the boom, the blocks inside the boom can twist if not on tracks creating a jam & finally you have an additional problem in the event of a failure inside the boom

On my system there is a block on the sail luff & the line returns to the gooseneck (then to the mastfoot) like the leech line in your drawing. So the purchase there is 2:1 to give increased downward tension on the luff. In that respect I need a longer line, but get better mechanical advantage
Your design can do that if need be.
The line to the leech is the same as yours, but he line runs from the end of the boom straight to the gooseneck with no blocks installed.
& for the life of me I cannot see what they actually do. On one side of the blocks you get 2:1 but on the other it is 1:2 so there is no mechanical advantage whatsoever. In fact friction reduces mechanical advantage

I was arguing this point with another sailor & rigged a set up on my bench with weights & proved there was no mechanical advantage inside the boom. The line which you pull in is the same as what you pull out & the only mechanical advantages are at leech & luff where one can get 2:1 ( if the luff line is bought back to the gooseneck similar to the leech line) or 1:1 on the luff & 2:1 on the leech as in your diagram

 

[blackbeard]

On my little boat (25') I have 5 mm reefing lines which work fine. Just a line, no balance blocks. Great care to reduce friction, I have ball-bearing blocks at cringles. Has worked fine over several years. Small size of lines gives no problem, but then, it's a small boat so loads not great.
Was originally 10 mm and ropes passed through the cringles, friction everywhere, which was utterly hopeless to the point of being unworkable and potentially dangerous.

 

[Javelin]

See http://www.premiumropes.com/splicing-rope/splicing-instruction-videos

To see how to splice / taper ropes - they have various videos.

I don't actually use their method as I seem to have devised my own over the years and despite a search I can't find a video showing the way I do it though Marlow ropes have a very similar method.
Almost all my lines on board are tapered it really helps with handling and friction overall, plus I can use small high load blocks which are much cheaper.