Setting up mast bend

[Torchy]

Quite soon (perhaps urgently) I am going to need to replace the UV degraded dyneema setting the tension on Loco's diamonds.

How do I do this?

I am thinking that I hold mast bent with kicker whilst replacing them:
* How do I get the tension the same ie high enough and the same each side?
* Do I 'overbend' the mast, tie the cords (accurately to the same length), then let the kicker off?
* Do others use bottle screws? (it seems this might be easier)

[JimC]

I've always done diamonds/caps with the mast off the boat, just using the lashing. I use a steel rule to make sure I have the lengths the same - assuming I am confident everything is symettrical - and then check the mast is straight afterwards. I think I'd tighten (and slacken) them progressively on both sides rather than pull all the tension on one side and leave the other slack. I'm not sure what could go wrong if you put all the load on one side and none on the other, but I just feel happier doing it that way.

[Torchy]

Thanks Jim...seems fiddly and difficult to tie knots that won't creep

I did a bit of a trawl and found this discussion:
http://www.sailingsource.com/cherub/forum/index.php/topic,1095.0.html

[Torchy]

PS Just realised who JimC must be and have really enjoyed some of the articles you have on a site somewhere (your blog?)

[JimC]

seems fiddly and difficult to tie knots that won't creep

The way I figure it, with a lashing of ten times or more a few mm creep turns into a few tenths of mm creep on the length and isn't going to make a blind bit of difference!

[Torchy]

Certainly thinking of trying that...it IS how it has been done previously...just wondering how fiddly it is to set up.

Accurate measurement using metal rule does seem a good starting place and see if I can get it to stay. Once set it stays set, for us, for now anyway.

[Phil Alderson]

I tend to unhook the shrouds from the spreaders, and tie them about the right length, while loose then hook them back up, sight along the mast and adjust, repeat as nessicary.

Accurate measurement is dependent on the shrouds, spreaders, and holes being symetrical.

[john_hamilton]

if you can, unhook from spreaders, its so much easier

[Torchy]

Hi guys...Loco has separate shrouds and 'diamonds'

To save another thread...what rope for spinnaker halyard? Loco's has nearly worn through where the halyard hits the block when hoisted ie near the middle

[simon_jones]

We always do the bend off the boat this is done by placeing the end on something higher than the ground, then one of us pushes the mast down in the centre while the other adjusts the caps. We have in the past used rope to tie these off but moved to bottle screws as this allowed us to get the tension exactly the same on both sides.

[Torchy]

Thanks Simon, equalising tension seems to be the issue and off the boat the way...will try KISS first (keep it simple, stupid), using dyneema and if not good enough move to screws.

[phil_kirk]

Doing it of the boat often requires supporting the mats at the ends and pushing down in the middle to create the bend then tightening up the diamonds/cap shrouds.  Doing it a bit at a time like Jim said is sound policy.  I have also, when on my own, made adjustments on the boat.  With the boat on it's side and the boat breaker eased take a line from the tip of the mast to the main sheet bridle.  Tighten the boat breaker to give some mast bend and tighten up the cap shrouds.  You may need to do this in several stages to get it right.

Sight along the mast to check straightness. ease or tighten as required.