Splicing dyneema to the clew-end of genoa sheets

[roaringgirl]

Currently, the genoa sheets are 16mm polyester braid-on-braid. They have eye splices in the end and are attached to the clew with soft-shackles (on this size of sheet and sail, using bowlines is frankly dangerous whenever the clew flaps during sail changes).

I have discovered that the eye-splice is too wide to fit through the jaws of the whisker-pole. On our looming ocean crossing, we will be spending weeks wing-on-wing so I need to solve this problem. My plan is to remove the eye-splices and then splice a metre of dyneema into the end of the sheet. My force calculations show that 6mm dyneema should be sufficient, and I have this on board. This will easily pass through the jaws of the pole and the transition from dyneema to polyester should not be nearly as bulky as the previous eye-splice. This will allow the pole to slide on the sheet all the way up to the clew without obstruction.

Is there a reason I haven't thought of why this solution would be a bad idea?

 

[LadyInBed]

To attach my whisker pole I have spliced the two ends of fairly stiff laid rope together to form a quoit. It is held in place on the soft shackle along with the sheets.

 

[roaringgirl]

When we use our pole, we use it with a topping lift, foreguy and afterguy, the jaws should be able to slide freely on the sheet so that the sail can be reefed independently of the pole.

 

[Minerva]

Can you not just either get sheets which are a little thinner or one long sheet cow hitched onto the clew?

 

[Kukri]

Experimentally, we replaced the port 22mm braid on braid genoa sheet with 14mm covered Dyneema, leaving the starboard one as it was, to see which we liked better.

So far, so good. The Dyneema sheet is far easier to manage in tacking. The only downside is that the very hard Liros dyneema is a (…!) to splice.

Solution might be a double length and a cow hitch?

 

[CJ13]

If you strip the cover its very easy to eye spice Liros dyneema.

 

[Kukri]

If you strip the cover its very easy to eye spice Liros dyneema.

True. I was just trying to achieve a covered splice.

 

[Wing Mark]

Currently, the genoa sheets are 16mm polyester braid-on-braid. They have eye splices in the end and are attached to the clew with soft-shackles (on this size of sheet and sail, using bowlines is frankly dangerous whenever the clew flaps during sail changes).

I have discovered that the eye-splice is too wide to fit through the jaws of the whisker-pole. On our looming ocean crossing, we will be spending weeks wing-on-wing so I need to solve this problem. My plan is to remove the eye-splices and then splice a metre of dyneema into the end of the sheet. My force calculations show that 6mm dyneema should be sufficient, and I have this on board. This will easily pass through the jaws of the pole and the transition from dyneema to polyester should not be nearly as bulky as the previous eye-splice. This will allow the pole to slide on the sheet all the way up to the clew without obstruction.

Is there a reason I haven't thought of why this solution would be a bad idea?

Thin dyneema is quite good at sawing through things.
It's also 'low chafe' not 'no chafe'.
So maybe add a cover of polyester braid or something?

 

[riverteign]

I find with Liros dyneema it helps to give it a bash with a hammer as you pull the cover back down. When it has locked up it loosens it up again and you can keep moving,

 

[jdc]

When booming out the genoa for a downwind ocean passage we always use a guy separate from the normal sheets. The guy is connected to the clew with a smallish bowline and passes nicely through the pole.

The reason to use a guy instead of the sheet - thus three leads to the clew - is that the pole inevitably chafes the sheet or guy (it can be 2 more 3 weeks rubbing in the same place). A really, really, bad place to have chafe is in the genoa sheet very near the clew as you then have to toss it away, whereas some chafe within 50cm of the end of what is an over-long guy is no issue, just chop it off before the next ocean passage.

You can just see in this picture the guy - red and white - and the sheets lying slack in the primary winch. The pole, btw, has a bridle with two fixed length ropes to the rail and an uphaul whioch keeps it all secure. We can roll away the sail without touching the pole.

 

[dunedin]

Currently, the genoa sheets are 16mm polyester braid-on-braid. They have eye splices in the end and are attached to the clew with soft-shackles (on this size of sheet and sail, using bowlines is frankly dangerous whenever the clew flaps during sail changes).

Pray why are bowlines “dangerous”, if done properly? So far over 25,000 miles and not had a problem with bowline on genoa sheets, including trans Atlantic when 90% of time poled out.
Unless it is a tiny boat, 6mm dyneema sounds more dangerous, as (a) so thin it would be a danger if anything caught in it under tension and likely to saw through pole end fitting; and (b) splice introduces extra risk of splice failing.
We use Liros cruising dyneema attached with bowlines and will stick with this.

 

[Kukri]

I have had problems with bowlines on genoa sheets! Specifically we had a set of sheets, not now used, which just untied their bowlines literally in a few minutes, and since then we have religiously added three cable ties to each bowline.

 

[dunedin]

I have had problems with bowlines on genoa sheets! Specifically we had a set of sheets, not now used, which just untied their bowlines literally in a few minutes, and since then we have religiously added three cable ties to each bowline.

Not sure what you are doing with your bowlines, as never had this issue. When first tied we always make a point of winching the sheet tight the bed the knot in.

 

[Kukri]

Not sure what you are doing with your bowlines, as never had this issue. When first tied we always make a point of winching the sheet tight the bed the knot in.

I do know how to tie a bowline. So does my son, who is a career deck officer as well as an RYA instructor having been a Sea Cadets instructor and of course holds an EDH certificate. We checked each other’s knots.

This was the first time that this happened to me in fifty years of owning cruising boats. So it is perhaps conceivable that one day it may happen to you, or to someone else. Which is why I mentioned it.

 

[dunedin]

I do know how to tie a bowline. So does my son, who is a career deck officer as well as an RYA instructor having been a Sea Cadets instructor and of course holds an EDH certificate. We checked each other’s knots.

This was the first time that this happened to me in fifty years of owning cruising boats. So it is perhaps conceivable that one day it may happen to you, or to someone else. Which is why I mentioned it.

I should have added a smilie - I know you have a lot of experience. But one knot coming undone in 50 years is probably not a reason to change away from a proven technique. Suspect soft shackles on a jib clew will have a greater failure rate than once in 50 years - most things do

 

[Neeves]

All our headsail sheets are one long dyneema rope joined in the middle with hollow dyneema tape. The tape is slid over the dyneema sheets and sewn in place leaving about 300mm of empty tape. The empty tape is cow hitched to the clew. The tape is sewn to the dyneema sheet using braided dyneema fishing line. The end of the tape, which is prone to unravelling could be sewn into the sheet but being lazy we have whipped it and then sewn over the whipping. We use this for our furling Genoa and large (as big as the main) screecher. The clew ring is still ahfty bit of stainless (but cannot think of a way of making it less of a missile) but tacking is no longer an issue. The joint is not much bigger than the sheets. There maybe some slippage of the cow hitch, but we have not noticed it and the sheets inside the tape provide stops for any slippage. The sheets are 10mm dyneema with polyester covers.

There is dyneema and dyneema - some is not very tactile and very difficult to sew, but good for halyards. You need strong needles and a palm to sew it.

If you don't fancy sewing - most sailmakers will do it for you.

Not my idea - introduced to me by Pryde in HK but then we used nylon hollow tape, dyneema just brings it unto date. With nylon we did have failures, of the stitching, now it last forever.

If you need to remove the sheets it can be difficult, narrow nosed pliers work well. If we remove the sail we remove the sheets as well and store together.

Most rope makers make a dyneema cover, hollow tape.

Sewing rope to make an eye etc is common place. These are bridle ropes, both with a shrink fit cover, which you would not have on a continuous sheet. The shrink covers for cordage is available of varying diameters off eBay or some rope makers. We have used sewn eyes when using Low Friction Rings, I find I get a tighter fit with sewing (and then sleeving). Sleeving makes the 'splice' stiffer which has advantages in some applications.

Jonathan

 

[roaringgirl]

Re: danger - I've experienced the heavy bowlines hitting things, (including my face) when the sheet is loose. Using eye splices and soft shackles eliminated this issue.

Re: strength - 6mm dyneema has a breaking strain of 40,000N. The combined sail-area of the whole boat is roughly 600sqft. If this were all genoa, in 40kts of wind, it would exert a force of 20,000N on the sheet.

 

[Roberto]

Re: danger - I've experienced the heavy bowlines hitting things, (including my face) when the sheet is loose. Using eye splices and soft shackles eliminated this issue.

hmmm
FWIW, I find equally frightening to bowlines the single metal eye pressed into the cloth and the various kg of all the clew reinforcement pads etc furiously flapping around; in other words no way I would get in the way of a flapping (biggish) genoa clew, be it bowlines, soft shackles or anything else it may be tied to.

 

[roaringgirl]

hmmm
FWIW, I find equally frightening to bowlines the single metal eye pressed into the cloth and the various kg of all the clew reinforcement pads etc furiously flapping around; in other words no way I would get in the way of a flapping (biggish) genoa clew, be it bowlines, soft shackles or anything else it may be tied to.

You concede then that reducing weight there reduces the danger.

 

[Neeves]

I'm with Roberto - the clew ring is enough danger by itself on a large Genoa. Using a soft shackle and/or eliminating a bowline is still going to leave it as a danger of which to be cautious. Removing the bow line should make tacking easier, no hang ups, the reduction in danger - not part of the equation for us (35m^2 headsails). Our 45m^2 screacher has tape instead of a clew ring - but it is still treated with respect.

Jonathan