Changing the stays or trap wires

I am thinking of changing from the wire stays and trap wires to an all high strength line system for the blade. Anyone done this yet? Should the same lengths be used or do I need to adjust it some?

Thanks
jody

Jody,

check out what Eric Precourt has to offer: http://www.precourt.ca/

I would prefer a system which was easy to adjust, so some kind of adjustment on the stays like erics would be an idea. Synthetic stays on beachcats are not well tested, and reports have been mixed.

Trapeze lines are well tried and a "no-brainer". Go for the same length, but look out for chafe. Spectra/Dynemaa 3mm is good enough in my experience.

I've been using 3.5mm D12 for the stays and 3mm for the trapeze for 4 years now without any traumas or problems. I've now refined it to a stage where I no longer have adjusters as its just as easy to adjust the line lengths. Its cheap, easy to adjust, easy to splice, hard wearing and very very light in weight, I'm surprised that more people are not using it <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

Wayne, I tought it only fair to warn Jody about mixed reports first off. We are definatly starting out with synthetic stays on our boats when we rig them. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Any pictures from your boat and how you do it would be very appreciated..

Ok I think I am gonna try it. Anyone know the lenghts needed for the VW blade, would save me from dropping the mast this week and measureing.
Thanks
Jody

A friend did this on my old HT with 1/8 (I think) vectran.
What kind of line are you going to use?
Unless you use PBO or dynex dux (pretty certain they don't come in small enough diameter and they are very pricey) then make them several inches shorter because they will creep. On the HT I think the side stays crept like 4 inches or so. Makes it difficult to really make them to a length that you can still use the staymaster adjusters. On trap lines it isn't as big of a deal.
In the end, I think the trouble of line as stays from a length, creep point of view outweighs any advantage they have.

If you do go ahead and do it then use a lashing type system on both sides so you can have plenty of play to tighten them. My friend's vectran (at least 20-25 feet maybe) may have even crept 5-6 inches.

I am just doing it. I discovered some abrasion on my sail, where it comes to contact with the wires. Hence I decided to take synthetic fibres.

From a pure technical point I would take PBO from 'easyrigging'. I dropped this idea, when I saw the price. There are only a few fibres which are ok for wire replacement (apart from PBO): Vectran, Aramid and Dyneema. Vectran would have a too large diameter for the same load. I didn't find any offer for covered Aramid, which I could splice, hence my choice was dyneema. I decided for Liros regatta 2000, because it has a cover, which adds UV protection. The drawback is that I needed one day for making half the splicing work (I only spliced single braid ropes so far). I think that I will use single braid Dyneema in future and replace it more often. This would reduce the rope diameter as well, since the cover adds 1mm more diameter.

For the trapez lines I took 3mm (BL 500kg, hence margin of safety 10 to 5), for the shrouds 5mm (BL 1200kg, normal load would be around 200kg, but 'missuse' could lead to significant higher loading). Since I have no jib, I have two long bridle wires (each 5.8m) and a short fore stays (0.5m). The fore stay is 6mm rope (BL 2200kg, normal load about 700kg, hence m.s. only 3, but the stay of the hooter acts as a back-up). The bridle wires are 3mm wire.

The higher gauge of fore stay and shrouds adds about 2% more drag. That is nothing compared to my skill.

The lower weight, I didn't calculate it.

Length. Each rope creeps, even wire. Dyneema creeps more than other materials. However my boat is already fitted with 'adjustment devices', which are again dyneema ropes.

Safety. I will test my splicing work by tensioning each of the ropes (two trees, main sheet, ....) Though I am still a bit thrilled.

As I am still in the process, I don't have any live expierence yet. But I will tell you I have buy a new mast (hopefully not).

Cheers,

Klaus

Excellent! That was my one unknown factor. Thanks.
For us living in the white spots marked "here be dragons" on the beachcat map it is much easier and cheaper to get dynema and rig this ourself than getting the proper wire or dyform.

have alook at http://www.marlowropes.com/public/pageManager.cfm?page_id=132 where you will be surprised at the versatility of the D12. As to creeping, actually creep is the wrong word, the fibres tighten upon themselves under load and thus lengthen once first used. I tend to make up an approximate length, tie it between two supports and then sit on it, you can then readjust the end ( splicing only takes afew minutes )to the correct length minus about 25mm on the stays. After a few days they settle down and don't really move much.

The only down side I think is that you really need to change every couple of years the forestay as the spinnaker seems to " fray " the rope a little but 3.5 mm is much stronger than wire so theres a bit of tolerance left.

The other thing I would recommend is that on the 3mm trapeze line the loadings are fairly light and consquently the slippery rope tends to " creep " through the splice as its not tightening hard enough on itself. I now insert the end of the line 3 times through itself rather than the 2 as marlow recommends and have'nt had any bother since. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

As to increasing the drag by 2%, can you check that as my instinct would say .002 as that is a huge increase in drag

cD_shrouds = diameter_shrouds * length_shrouds * 2 * cd / area_sail, with cd of tubes, ropes etc. of about 1.
Going from 3mm to 5mm of 2 * 6m shrouds for a boat with 14m² sail area creats a delta drag of 0.0017. If the total drag of your boat is around 0.1, than you have an estimated drag increment of 1.7% = 2%.

Cheers,

Klaus

Be aware of the possible foibles of D12, I had a mast down last night due to a side stay splice coming loose, no real damage apart from my pride <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />. I would recommend that you definately go though itself 3 times on all lightly loaded ropes and leave one strand visible outside of the core as a telltail. Some 49er sailors say thay have even put a stitch through the tail to prevent this light load creep. Still haven't had a stay fail yet through breakage just the splices creeping though on the lightly loaded stays.

I agree 3 times is better. I've hopefully copied a link to explain how to do a "brummel splice" just in case you don't understand this thread.
http://www.precourt.ca/splice/splice1.htm
Clear as mud!

I prefer to not embed the end of the line inside the core, but leaving it on the outside with two half hitch knots.

Yep, that's what I do too.

The Brummel Splice won't work with the D12as its plaits are too close together, try the Marlow Web site http://www.marlowropes.com/public/pageManager.cfm?page_id=207 which has a nice simple piccie sequence <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Hi Waynemarlow,

So, you are using D12 as side stays? What is your expierence?
I had some time to continue with the rope rigging. Pre stretched the ropes and checked by that the splicing. Since I use double braided ropes, I have to burry all strands. I locked the splice by stitching with a fine waxed rope.

However tensioning the rigg was difficult and I have to say, that I am a bit concerned about the limited stiffness of the sidestays. But only a test sail can prove the concept.

Cheers,

Klaus

Hmmm yes they do stretch abit when new but soon settle down to a good " twang " as per the steel. I only have experiance of the D12 so not sure of the type you are talking about. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

It is covered 12 strand SK75, should be comparable.

Well, I have pre stretched them with about 300kg 10 times. Than put them on the boat and streched again. After one week (without sailing, but mast up and tensioned) I went sailing (strong winds) and after a few minutes they were stretched another 6cm. At the end that means the windward forstay and the main sheet has to take nearly all the load). Back on the beach I had to tension again. That is what I meant with "difficult to tension".

Regarding stiffness, it depends on the rope diameter of course. If you select the diameter by breaking strength (equal diameter for wire and D12), D12 will stretch 1% at 20% load and wire 0.2% at the same loading, hence wire is 5 times stiffer. To get the same stretch, you have at least to double the diameter. However I don't know how important shroud stiffness is, if your boat is conventional rigged (left and right shroud + one forestay). However if you have two forestays, it plays an important role.

If I have to re-tension again after the next sailing or if the leeward forsetay constantly comes slacky, I will switch back to wire <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />.

Cheers,

Klaus

OK then if the stays are stretchy how bad does this effect the boats handling and speed as to be honest I have always had the windward stay go slack regardless of whether I use wire or not, do I need to put alot more tension on. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Given the dificulty, cost, drag, durability, etc. of switching from wire to dyneema (or what have you) I wonder what is the benefit supposed to be?

Is this all just to reduce total weight on the boat? What about the wind drag of the fatter line vs. the skinny wire? Has anyone weighed their 3 wires (ok, 7 if you include both trap lines) vs. the lines? How much total weight savings is there?

Even most A cats are still using wires vs. line, at least for the rigging if not the trap wires too.

Hi Timbo,

I didn't calc the weight benefit. In theory dyneema is 7 times lighter than wire. However I don't believe that such a small improvment will improve the performance of the boat. I gave a guestimate about the drag some postings before, it is neglectable as well.
The main benefit of dyneema is cost. I would pay nearly 50%-75% more for wire including swaging and a plastic cover to protect the sail.

After another day with light wind (in the morning) and strong wind (in the afternoon). I think I will invest in wire. In light winds, it was fine. For strong winds and waves it is not stiff enough in my opinion.

Waynemarlow,

Agreed that the leeward sidestay will be slack. But the leeward forstay (if you have one) should not.

Cheers,

Klaus

Simple answer is.

Use wire for the stays and diamonds, synthetic line is just practical here/

But use lines for the trap-lines. There is absolutely no reason not the use line here. Cheaper, lighter, simpler, less wear on the batten pockets and safer (can be cut in emergency)

Wouter

Sticky back sailcoth on the batten pockets where the stay rubs works fine for this, replace when it gets worn through which is every year or so for me.

Elasticity in side stays while sailing is just wrong, might as well go back to cotton sails.

Darryn
Mozzie
1782

For me it was largely being able to set up my own shroud lengths easily and simply without having to constantly go to a chandler to adjust the stays, cost and weight was not really the issue, as an aside I lost nearly 3 kilos ( including the adjusters ) and had nice soft stays which didn't damage sails nor hands.

It would be interesting to go back to wire for a while and probably see what others are confirming that the D12 is just too elastic or perhaps not. Coming from a gliding background where there was some argument whether stiff platforms were better than flexiable ( basically the flexiable platforms took out all the shock and jolting allowing the pilot to thermal better vs the flexiable wings didn't allow the wing to perform as it should ). I guess trial and error maybe the answer. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

The 3M gunnal non slip is also good for protecting the batten pockets & last quiet a few years

I talked to Mike Krantz at Layline, and he felt that line for the traps was OK (his word) but that for the stays unless you go with the carbon stuff ($$$$) then he felt there is just to much creep. I have to believe that he would know since he could use any line he wanted on his F18 or A cat and still has wire on them. So for now think will stick with wire.

Jody

My concern is not about the small amount of weight you save, but the amount of wind drag you add by going from skinny wires to fatter line, and then add the risk of creep, and the risk of failure if something sharp rubs up against it. You would have to be constantly checking them for wear and nicks, etc. I would think.

I like the lower maintenance of wire because I leave my mast up most of the time. If I were keeping the boat on a trailor with the mast down and all stays coiled neatly in the box, maybe I wouldn't worry about using line instead of wire. Of course I could stop drinking beer and I would lose more weight than by switching to line too. <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

Klaus had calculated the extra drag to be a 2% increase. He made some posts about this early in the thread.

Well, it's a small increase but an increase anyway, and if it's blowing 20, going upwind, I'd rather not have any increase in drag up there. I count 3 stays plus 4 trap lines, so there are 7 fatter lines vs. 7 skinny wires.

My origanl reason for the line over wire was just easy of storage as we have to travel to all the regattas, but at the expense of creep and worse preformance I can handicap myself there with stupid stuff, so will have one less beer, and keep the wire for now.