Convert to Dyneema backstay

One of this seasons upgrade plans for my 320 is to replace the 5mm backstay with a Dyneema version. However, as always, my head is full of questions:

1. Is a 6mm "single braided" Dyneema similar to 5mm wire?

2. How much should the involved block in my aft-stay arrangement be able to withstand? (What size of block should I aim for?)

3. Has anyone carried out a similar upgrade?

stian,

Stian,

You can make a really expensive one using only blocks from Ronstan or you can do like me go for the budget model by using Selden blocks. I only bought one block from Ronstan which is the huge one at the end of the backstay.

Simple drawing:


Nr. 1: Ronstan Orbit Halyard block art no. RF79108
Nr. 2: Selden PBB50 Single block art. no. 405-001-01R
Nr. 3: Selden PBB50 Single block art. no. 405-001-01R
Nr. 4: Selden PBB50 Tripleblock art. no. 405-001-07R
Nr. 5: Selden PBB50 Trippleblock with becket and cam art. no. 405-001-10R

The purchase gained is maybe a little more than initially intended.

Sorry for the sketch showing a horizontal rather than in a portrait layout.

I have got the art. no. wrong.

Think both of these are sufficient:
RF74108 nok 912.-
RF64108 nok 681.-

I bought the last and cheapest one.

I will indeed talk to a professional rigger regarding these details, and have also been talking to him at several occasions and mentioned this.

From previous, and current, work-experience - I can tell that what most professionals charge you $100-150 an hour (Norwegian prices, though) - can easily be done yourself absolutely for free, and also provide me with some extra knowledge. As my current position offers a 1/1 schedule - I've got plenty off spare-time to "take from" for my little boat project, in addition to being my number 1 interest...

Compared to the work them "professionals" have performed on other Hanse's in my area, including my own, I'm 100% sure that what I've done on my boat myself holds an equal standard, or even better. Because I've got the time, the keen interest - and spends hours of investigation and reading before doing any major un-reversible change - I'm confident not "ruining" the sloop to a piece of unrecognizable white plastic.

Certainly forums like e.g. Myhanse.com provides the "base" of tips and ideas, supported by different articles and documents on the web. So far this has proven to be "far beyond" good - and in the rare cases where I've been discussing technical details with them pro's - I've been able to prove them wrong. But one day, this may prove to be wrong...

My motivation(s) for fitting a Dyneema backstay are, in prioritized order:

1. Get the backstay off my mainsail when tacking/jibbing. (And also to be prepared for my new main, when I've got them $ to invest in high-tech clothing...)

2. Get a better trim of my 9/10 rig. (Which leads us into my no 3.)

3. Better "ratio". (Today I would have to use the ST'er to tighten it up.)

4. Have a non-stretchable sheet for adjusting the backstay; today's cheap polyester bungee cord, probably cost me 1/10th of a secound for every 100 nautical mail I race...

5. Get a "flying lead" 450MHz antenna implemented for my CDMA-based   onboard Ice.net network connection.

6. The looks.