Lazy jacks - advice please

[KREW2]

I am in the process of redoing mine, too much slack and it looks like a bag of laundry on the boom, too tight and it starts to act like a topping lift.
I think it is important to have an adjustment system on them, so as to be able to slacken off when sailing.
I want to be able to adjust on the boom, rather than a rope going up the mast through a small block and back down.
as I have a stack pack I didn't think this was going to be possible, then I discovered this knot.

http://www.asiteaboutnothing.net/cr_most-useful-knots.html#adjustable-grip-hitch

Which I hope will allow me to tension it when moored.

 

[PuffTheMagicDragon]

On Cyano, the lazyjacks terminate on a stackpack type of bag. There are three terminations on each side made off to stainless triangles. The forward four are tied off to the triangles. The aftermost pair end in snaplinks to the triangles. The reason for this is that when I am at anchor, say for a weekend, I rig up a canopy as protection from the sun. To do this above the boom, the lazyjacks would get in the way. Therefore, the solution is to unclip the snaplinks from the aft triangles and re-clip them to the forward ones. This renders the lazyjacks loose enough to be pushed out of the way. (one can also do this unclipping on a long passage but I don't bother).

The line is 6mm (because it was available) braid although 5mm would also have been ok. The line passes through nylon thimbles: cheap and effective.

Incidentally, the bag is held in place on the boom by the footrope of the main. The triangles are sewn on each side of the bag with webbing near long 'pockets' through which I inserted two lengths of rigid plastic pipe of the type that we used to use for plumbing before the advent of Acorn. This gives the bag a better 'hang' when the two flaps of the bag are folded inside. Closure is by a long nylon zipper.

You might be able to make out the details if you enlarge this photo:

 

[Bosun Higgs]

What type and diameter of cordage would the Forum's pundits recommend for the lazy jacks on a 28-ft bermudan sloop?

Depends on how you want to work things. If you keep a topping lift, then all the liones do is stop the sail flopping over the edge of the boom and you could do this with 4mm cord. Thats all mine are on a 36 footer.

On the other hand I have often thought that you could get away without a topping lift if the cord on the lazyjacks was a bit heavier. Splice the two lines together as they exit the mast and lead them to a cleat by the cockpit.