Slieve, the only fault that I can see certainly applies to me and others as well, and simply put, it’s that we’re all getting older and can’t do as much as we used to do. In my case, Parkinson’s makes it extremely difficult for me to write accurately; but I can still draw (so long as I’ve taken my medication!). That’s why I think that there needs to be a collaborative team effort here, pooling skills and resources to ensure that everything that has been learnt about SJR is recorded into a useful document. You have passed on your knowledge to those members who have built SJR rigs, and it is now those members who should really be stepping forward to make a good record all that you’ve taught them, in order to pass it on again. By all means do as much as you can, but I don’t see why it has to be a solo effort. So come on, all you SJR sailors, it’s time to get to work! 

Anonymous wrote:All this discussion is leading me towards the view that there really ought to be a document on this website detailing the current state of the SJR art, building on Slieve’s original rough draft notes, and adding all that subsequent practitioners have proved to work. For example, I can find the broadseam calculator spreadsheet, but no notes on how to use it, and I don’t think that it gives dimensions for a mk2 sail. I can’t find notes on actually building a complete sail and rigging it, as the rough draft is incomplete, and it doesn’t give full explanations for some things that are advocated, such as the jibs being on the starboard side of the battens (this puzzles me). I’d certainly like to see a spreadsheet for the mk2 sail, and will undertake to develop a version of it with 5 parallel panels / 6 sheeted points, as a generic 2D CAD drawing that can be used to design and make offshore cruising sails. Like Slieve, I’ve retired from active sailing, but if I were still able to make a rig, put it on a boat and use it offshore, this would be what I’d favour, and I’d want to be able to access a full set of sailmaking instructions for it, as Arne has done for the kind of rig that he favours. If a wordsmith amongst us (Graeme?) will undertake to gather the info and draft such a document, I’ll undertake to employ such skills as I’ve acquired in 3D CAD modelling to illustrate it. 

What a beautiful idea David!

I think that many JRiggers would devoure such a writing.

I certainly would....

Mauro

Slieve wrote:

Hi Thomas,

There are an interesting number of points here, and possibly some simple answers.

Firstly, I don’t see why the Mk2 rig would not scale up well to 65sq.m. I have a spreadsheet which will give all the dimensions for that for the ‘standard’ shape (though I would have to check that is is complete) if you would like a copy. It may even give the broadseam depths and widths if going that way.

As to whether to add another panel my answer is that I would not like to increase the aspect ratio too much, so might draw a rig only half a panel taller and split it into 5 parallel panels, but I will admit that I feel that 5 panels given enough reefing steps because of the rigs apparent tolerance to sail area and the advantage that with split sheeting with 2 battens per sheet then the twist can easily be controlled when reefed.

As for additional controls for long distance cruising, the minimalist controls is one attraction of the rig. With no Hong Kong parrels, luff hauling parrels, fan up preventers you are left with a halyard, a pair of sheets, three or four combined downhaul/ batten parrels and either a yard hauling parrel or another downhaul/ yard parrel to make it work. In practice I would add shortish batten parrels to at least the top and bottom battens and to the yard for added security, and would discuss with David his comment on securing the boom (bottom batten).

One thought I have had for long distance sailing on a junk would be to have a detachable water sail which could be clipped onto the bottom batten and held down against the deck with bungees through rings stretched from toe-rail to toe-rail. When sailing in light conditions closing the gap below the sail could give some extra drive. It could be made from spinnaker material, with a couple of small areas of window material and probably not need a slot. But as I say, just a thought.

As for working out where the CoA of the existing multi headsail rig is, count me out.

And don’t forget, I’m biased.

Cheers, Slieve.

All this discussion is leading me towards the view that there really ought to be a document on this website detailing the current state of the SJR art, building on Slieve’s original rough draft notes, and adding all that subsequent practitioners have proved to work. For example, I can find the broadseam calculator spreadsheet, but no notes on how to use it, and I don’t think that it gives dimensions for a mk2 sail. I can’t find notes on actually building a complete sail and rigging it, as the rough draft is incomplete, and it doesn’t give full explanations for some things that are advocated, such as the jibs being on the starboard side of the battens (this puzzles me). I’d certainly like to see a spreadsheet for the mk2 sail, and will undertake to develop a version of it with 5 parallel panels / 6 sheeted points, as a generic 2D CAD drawing that can be used to design and make offshore cruising sails. Like Slieve, I’ve retired from active sailing, but if I were still able to make a rig, put it on a boat and use it offshore, this would be what I’d favour, and I’d want to be able to access a full set of sailmaking instructions for it, as Arne has done for the kind of rig that he favours. If a wordsmith amongst us (Graeme?) will undertake to gather the info and draft such a document, I’ll undertake to employ such skills as I’ve acquired in 3D CAD modelling to illustrate it. 

Here is my last proposed sailplan again, this time shown deeply reefed to only three panels. I have often sailed with only these panels set, either when entering the harbour, when trolling for mackerel or when the breeze suddenly increases. I am very glad I have kept this Hasler-McLeod type top section, as it gives me so much extra sail area for a given mast length.
This has led me to add the Fan Up Preventer. I can live with the moderate extra attention this needs.
The FUP, the YHP and THP are not being touched unless I am to alter sail area.

As for the HK parrels; these are standing parrels. After initial setting up (takes 2 or 3 outings), I just forget about them. The job of the HK parrels these days is actually just to stabilise the sail and make it believe it is flat. Simple as that.

Cheers
Arne

PS: Don’t forget, I am biased too...☺

(full size diagram in Arne's sketches, section 9)

Anonymous wrote:

Thomas Nance wrote:

Thanks Arne for the sail drawings. From what I know, it seems a sail with around 33% balance forward of the mast is needed to place the mast in the ideal location, anything less puts it in the bullhead or right where your head lays on the forward berth. 

...

Thanks again for all your time

Funny that, Thomas.
Unless your boat differs from the plans (see below), the mast will not hit any of the bunks. However, I would consider offsetting the mast 10-15cm to port to ease the access. That will have no negative effect on sailing.

Arne

PS: Where did you plan to position the mast?