Tuesday, March 25, 2014

Dyneema Rigging

When Zuline was launched she had beautiful hand spliced galvanised rigging. It was done by a very talented friend and it was very effective rigging. It was also very heavy - heavier than it needed to be.
Roll forward nearly 10 years. Zuline's mast was in sad need of some care and attention. She was launched in mid winter and it had been very difficult to get varnish to go off in the cold community hall where the mast had been. Consequently she was launched with only about 3 coats of varnish on the mast. We had chased the varnish for a number of years, just keeping ahead of it from a harness suspended from a halyard. A period of ill-health had put a stop to that and the mast had deteriorated.
We decided, after much agonising, to pull the mast out, strip the mast back to bare wood, make the minor repairs required and then get a decent cover of varnish on it.

On December 16 last year the mast came out, and it was a sorry sight. We set it up on trestles and got loose with the heat gun and scraper to remove the remaining varnish. It quickly became apparent that we might as well do a proper job and remove all the hardware as well. We needed help!! So we engaged a local shipwright to remove the hardware, do the minor repairs, sand the mast and prepare it for varnish. Once done Celia put 6 coats of Werdol Rapid Clear then 6 coats of Werdol Clear Varnish on both the mast and the boom. We are very impressed with this system so far. The Rapid Clear requires no sanding and only 5-6 hours between coats. So you get a quick build of product with lots of UV protection. Then the Clear Varnish requires sanding and 24 hours between coats. After this the spars looked glorious.

Meanwhile we had decided that all the near water stays (bobstay, whisker stays and boomkin stays) needed replacement. However we couldn't find anyone in Melbourne to splice them up in stainless. Eventually I tracked down Joe Henderson in Sydney who said "Put them in the post. We can splice them in galv, though I wouldn't recommend it, stainless or Dyneema." We settled on heat set Dyneema with overbraid.
Between Christmas and New Year we took a good hard look at the other stays and realised that whilst they mightn't all need immediate replacement they would soon enough. We took the tough decision to re-rig completely in Dyneema with overbraid. This was beginning to be a money pit. That's the problem with unexpected expenditure.
The thimbles were made on a CNC machine from Aluminium bronze with files provided by Joe

The Bobstay is 13mm Dyneema with Overbraid and served overall

Stays for a Lyle Hess 32 foot cutter

Whilst we were at it we embarked on a mission to remove anything hard or heavy that had been damaging the spars, particularly the bowsprit. As well the stainless lifelines gave way for new Dyneema ones.
The bronze piston hanks from the two headsails were quickly removed with a set of bolt cutters and replaced with our own design of Dyneema soft hanks.
The hanks were made from 2.5mm Dynex and are captive on the sail

Finally the big day arrived and the mast was stepped. It was a great relief to have all the work come to fruition after almost 4 months out of the boat.

The end result is a different rig entirely. We removed 9kg of near water stays and 52kg of above deck stays. In their place we put back 3kg of near water stays and 13kg of above deck stays - and that includes the bronze bobbins. This represented a 74% saving in weight! Further weight reduction has come with the removal of the stainless lifelines, removal of stainless shackles and replacement with soft shackles, removal of reefing winches and a rethink of reefing...Overall the weight reduction is of the order of 70kg.
Joe Henderson was pleased with the outcome - and so are we. Joe had to remake only one stay on the day after launching and that was a quick and simple exercise. All the others fitted perfectly out of the box...and they look the part.
A happy rigger with his work

Now we just have to tackle the rest of the varnish. After the mast, that all looks quick and simple!