Using dyneema for rigging - warning

[Robert Sheridan]

We had a go with a dyneema bridle for our Tiki 30 at the suggestion of the rigger as it is hard to make up hard eyes on 6mm wire. The dyneema stretched really badly the first time out, we retightened and it stretched again (to such an extent I had to set up the spinnaker halyard as a forestay) so we are going to go back to wire.

We have since found out that there are forms of dyneema that 'creep' less than others, but it all creeps to some extent.  The stuff we had was apparently from Liros and the supplier is getting back to them.

So.. if you are thinking of using modern braids for rigging check their stretch and uv characteristics  very carefully before buying and also make sure you are supplied something with a cover to protect against abrasion.

[Ian R]

Ref deadeyes for dyneema, I have almost finished my 8 no. deadeyes for 6mm Marlow prestretched I have been making from CARP(engineering grade, low water absorption) tufnol/elm laminate, now sheathing with carbon cloth. I reckon I will have just about made the minimum wage on the hours spent, compared with buying them, however I have learned a lot about making blocks and using tufnol. The elm section is the pointed topend part (a filler essentially) simply because it was easier to hand cut the main part as blocks from an offcut I bought on Ebay (about £20), which was too small for the overall block size, and stick on the well seasoned elm. I grooved the blocks by hand with a 6mm chisel, making the scribing cuts with an old  scrap Jap back/pull saw. I've got plenty of carbon cloth (I sheathed my outboard sled with it which is effectively, very tuff) so I'm laminating carbon up the sides before I make the drillings for the lashings afterwards then white 2 pack paint. The tufnol dust is pretty nasty, for the record,  and I would only machine cut it with extraction and airpowered facemask which I habitually use as everyone should do.

Buying the titanium  production ones would have been very nice, but the point is I have had to do a lot of reading up on dyneema, rope tests, blocks, radii etc, and have had to learn how to make the blocks. Since I have been making mastfittings in stainless at the same time, I know I can be confident of fixing anything that goes wrong at sea myself with gear I have onboard, (cutters, material, drills, grinders, crimpers, dyneema gear etc).

Currently I have no phone/camera etc, but will post photos of the finished blocks eventually . I could get into self -blockmaking with tufnol and standard bearing  parts etc., I have enjoyed that (but not the stainless drilling though!) You might guess that I'm proud of me blocks!

Tight lines!

[Éric Bouvéron]

Ian,

I certainly wish to see that!

Éric

Ian R said:

Ref deadeyes for dyneema, I have almost finished my 8 no. deadeyes for 6mm Marlow prestretched I have been making from CARP(engineering grade, low water absorption) tufnol/elm laminate, now sheathing with carbon cloth. I reckon I will have just about made the minimum wage on the hours spent, compared with buying them, however I have learned a lot about making blocks and using tufnol. The elm section is the pointed topend part (a filler essentially) simply because it was easier to hand cut the main part as blocks from an offcut I bought on Ebay (about £20), which was too small for the overall block size, and stick on the well seasoned elm. I grooved the blocks by hand with a 6mm chisel, making the scribing cuts with an old  scrap Jap back/pull saw. I've got plenty of carbon cloth (I sheathed my outboard sled with it which is effectively, very tuff) so I'm laminating carbon up the sides before I make the drillings for the lashings afterwards then white 2 pack paint. The tufnol dust is pretty nasty, for the record,  and I would only machine cut it with extraction and airpowered facemask which I habitually use as everyone should do.

Buying the titanium  production ones would have been very nice, but the point is I have had to do a lot of reading up on dyneema, rope tests, blocks, radii etc, and have had to learn how to make the blocks. Since I have been making mastfittings in stainless at the same time, I know I can be confident of fixing anything that goes wrong at sea myself with gear I have onboard, (cutters, material, drills, grinders, crimpers, dyneema gear etc).

Currently I have no phone/camera etc, but will post photos of the finished blocks eventually . I could get into self -blockmaking with tufnol and standard bearing  parts etc., I have enjoyed that (but not the stainless drilling though!) You might guess that I'm proud of me blocks!

Tight lines!

[Ian R]

Here are the deadeye blocks. The micrometer is set @ 1/2". I haven't decided yet whether to varnish or paint...the blocks are sitting on the elm that the pointed part of the deadeyes are made out of. The holes are for 1 no. knotted end cord, then 2 no. double lashings.

[Ian R]

[Éric Bouvéron]

Ian,

Bravo!

If I dare: paint them. Varnish is a pain to maintain.

But, that's a great job!

Éric

[Ian R]

Bonjour Eric,

Yes, I will have to paint them sadly, but I show them like this so you can see where the laminations are. I have enough brightwork on the boat already, the beam support blocks are like this so I can see any incipient rot but there is of course a labour cost to maintain. I pressure- washed her yesterday and because she was sheeted over for winter (ie half the year this time) and the tillers were covered there are only a couple of places where the cover sheets have rubbed the varnish for recoating thankfully.

Looking at those drainholes at the beam blocks , while pressure washing the muck out, I thought again, no matter how I have tried (and that's taken a lot of time) it's very hard on this boat to design out the faults in surface water drainage. I have been fairly successful but I would be more successful if I had another lifetime ...The water draining turned some lashings green but I blasted it off. For s/h buyers you need to be aware of these faults, because they are faults, and look for the rot where the rainwater lodges and can't easily drain at/in the cockpits and at the beam support blocks of the Tiki 31.

I only have one mast fitting left to make and the masts can be stepped and rigged. My 6mm cobalt bit burned out this afternoon and I'm trying to regrind the set before making the last fitting, ie not having to buy another lot of cobalt bits. I'm off to France for a while soon: since winter has eventually stopped, the grass is growing....the masts are waiting to go up for when I return.

Just one other thing, I was talking to a Woods self- builder yesterday, we happened to mention NOT screwing on the rubbing strips to your keels as advised in my (very old) plans. Woods stresses not to penetrate your epoxy/paint surface, I thoroughly endorse this, that's why there are NO holes in my beams/keels/hulls only than mastic screwed/fixed flat tufnol captive rebates for boards under beams 2 and 3 for the centre deck. No through holes at all, as they are, practically speaking IMPOSSIBLE to protect properly. There are no holes (ie epoxy/counterbored) of any description in my hulls apart for the rudder lashings and the U bolts for the bridle.

A bientot   Ian

[Ian R]

If there are any xylophiles out there (timber fanatics), if you look at the edge of the elm board in the photo you will see the tracks of the elm beetle that killed the tree. Usually, when this happened, after felling, the bark later detached from the wood. The bark beetle carried a pathogen which compromised the way nutrients were transmitted through the tree, and eventually killed it. This is historic now, since few elm remain in Europe of any size or age.

This plank is over 20 years old, I still have some 2" thick full width (eg 30/32") elm boards I converted and kilned over 20 years ago as well as the 1 1/4" boards like this. I can remember some of the trees that the timber came from, and in the case of the 2" boards know exactly the site where I bought them. I'm still using it on my boat, it's light, but it's only good either above the waterline or below it, ie full submersion or dry. The beam blocks I have on my boat are from this, I need to keep an eye on them for that reason. Fortunately the elm moves less than oak, which is always moving, and has a better chance of holding the epoxy coat. I have used many tonnes of oak in housebuilding, it's a difficult timber sometimes, but it's sustainable unlike the tropicals which I try to avoid, though I use them occasionally when there's no suitable alternative.

Elm was used for building gigs, because it's light and tough. I sold many of my best trees to gig-builders.

Small batch production was started in the industrial revolution in England when at Portsmouth the Navy made basic machines to make rope blocks, I've visited the shed and seen the machines. I was conscious of a kind of full-circle when making these by hand for myself incorporating elm, which was the choice timber for that purpose in those days.

Hope I haven't bored you,.... I'm a timber-obsessive.

[Axel]

I'm now ready to start making rigging pieces for my T38 and pondering the deadeyes.... the cost of buying them is prohibitive and so am thinking of different ways to make them. Since I don't have access to a lathe or machine tools, I have made wooden pulleys in the past by laminating oversized cheeks to a central cylinder. I am wondering whether this would work for deadeyes?

My idea is to cut the center, drop-shaped load-bearing portion of the deadeye from aluminium plate, perhaps 10mm. Then glue and/or mechanically fasten slightly oversized cheeks of thinner plate to this piece to provide the groove for the line. If I make all 3 pieces from Al. then it would be simple to sand tumble all the parts in my cement mixer to smooth them out, as I did for the mast fittings. Seems to me this would be pretty straightforward; all the pieces can be cut with a bandsaw and just the holes would need radiusing. The shaping of the holes should be easy enough with a file or a dremel tool. I suppose this would work for wood too though for such high stress parts the idea of using 6061 is attractive. And I have enough surplus from making my mast cranes and feet lying around. 

Before I start, feel free to comment with any experience or ideas...

[Éric Bouvéron]

Sorry, it's in French, but that's the best I found. Resin made with a mold. supposed to hold 9 tons. I am not patient enough to do that, but it may be faster and stronger if you make a few of them. If some words are too difficult for google translate, let me know and I'll help.

http://etpartoutlamer.canalblog.com/archives/2015/08/28/32552684.html

[Omar M. Rashash]

The Spirit of Gaia, a Pahi 63, uses wooden deadeyes and chain plates, coupled successfully with Dyneema stays.

[boatsmith]

Éric Bouvéron said:

Sorry, it's in French, but that's the best I found. Resin made with a mold. supposed to hold 9 tons. I am not patient enough to do that, but it may be faster and stronger if you make a few of them. If some words are too difficult for google translate, let me know and I'll help.

http://etpartoutlamer.canalblog.com/archives/2015/08/28/32552684.html

nice,, thanks for that

[Axel]

Thanks Eric and Omar.

Eric, I really like the resin deadeyes but I fear they would be more work than making them out of wood or aluminum. If I need 50 of them that would be the way to go! I suppose I should clarify that while I can make them out of solid wood I am not in the frame of mind to patiently hand carve the grooves out and so am trying to come up with a way of doing it that is quicker and easier. My idea seems so simple to me that I was hoping, (sorta') that somebody would shoot it down...