Block size and dyneema tack line size for helix furling gennaker

[dune16]

I am getting a north sails 98sqm helix top down furling gennaker for my Lagoon 42 cat. General concensus is do not attach the furling directly to the bow sprit, instead have a 2:1 tack line. I am trying to go with something similar to the photo (although that's a racing boat so high spec, higher loads etc.). I am unsure of the block size I would need and what size dyneema for the tack line? Any ideas? Thanks

 

[Neeves]

What is the size of the dyneema halyard and the specification of the torque luff line? I assume its a 2:1 dyneema halyard. (My knowledge may be superseded by better cordage - you will also know to leave the halyard on the winch, don't trust the clutch).

Jonathan

 

[dunedin]

I am getting a north sails 98sqm helix top down furling gennaker for my Lagoon 42 cat. General concensus is do not attach the furling directly to the bow sprit, instead have a 2:1 tack line. I am trying to go with something similar to the photo (although that's a racing boat so high spec, higher loads etc.). I am unsure of the block size I would need and what size dyneema for the tack line? Any ideas? Thanks

View attachment 147312

Ask North Sails, they are experts in this

 

[GHA]

Low friction rings might be worth investigating as well instead of a block. Multiple falls would reduce the force needed on the line, maybe cheaper than a single block. Not too hard to splice thin-ish dyneema into thicker polyester also, nicer to use.

Sort of but not quite >>

 

[Daydream believer]

Once you have found the optimum length why is the concensus an adjustable tack line?
Apart from access to fit & remove, will you be adjusting when under way? If so will you not be able to do this on the halyard? Presumably you will not be letting the tack fly, complete with the weight of the furler swinging around. Or is it because you have a cat & cannot reach the contact point from either bow. Hence, need the adjustment?
Otherwise, it seems that you are just adding an additional failure point. Plus tying up additional fixing points for the control line.

 

[dune16]

Having had more feedback I think the setup to go for is as described but instead of a block use a low friction ring. Regarding adjustable tack line, I agree, this may not be necessary so perhaps it will all end up as a fixed setup, I was just copying what I have so far found other Lagoon 42 owners online to be running

 

[Neeves]

Most such furling sails, or the ones I see, are dropped on deck when not in use (though we furl and keep rigged). If you are going to pack the furled sail away having an adjustable line will make it easier to remove or you need to wiggle up an uncomfortable prodder. From memory Lagoon prodders are not long - so maybe its not an issue. You may need the purchase system to keep the lines separate and usure its the furler that rotates - not the whole assembly. If you intend removing the furled sail you will desire some sort of quick and simply means to release the tack

We need a winch to tension the halyard/luff - it would be impossible by hand (but you need to release, slightly, to furl - and you need a winch that can be dedicated for the sail.

Jonathan