Lazy jack rigging question

[chriscampbell]

I have a new-to-me boat that has 4 lazy jack lines with eye splices coming down from the mast. I do not have the lines to rig them to the boom, but the boom has an eyelet on one end, plus two hooks, on each side. Someone at my marina told me this configuration allows an "M" shape to be rigged using shock cord. You can simply unhook the cord from the boom and push the line up to the mast to get them out of the way.

My question: I want to order the shock cord. What thickness should I get? I've seen lots of references about 1/4" being fine for lazy jacks, but does that still apply for shock cord? Is 1/4 going to have enough resistance to catch the sail?

Here is what it might look like on each side, with the red being the shock cord:

Thanks!

 

[Tally Ho]

My boat is quite a bit bigger, but my jacks are set up so I can loosen or tighten them(or even pull them all fwd to the mast so I can drop the Mack Pack.

Mine are all rope (no shock cord).

Greg

 

[Justin_NSA]

You're missing the part of the system that lets you tighten or ease the lines. Like Greg mentioned, you don't need shock cord

 

[Mark Maulden]

Use dyneema. Less chafe

 

[Hollyberry]

We had a shock cord system on our last boat. The same “M” that you are proposing. It worked fine, you need to play around with the tension , and adjust some as they age.

Rather than take them forward to the mast we added another section of shock cord to the cabin top handrails with a hook at the end and gathered the “M”s and stowed them on the hooks attached to the handrails. This opened up the gap and made raising the main easier. We “deployed” the lazy jacks only when lowering the sail. Less chafe on the sail.

Removable lazy jacks also allow you to use a conventional sail cover - no slots, flaps, etc that is common with fixed lazy jacks.

 

[chriscampbell]

Thanks, everyone. My plan was to unhook the aft two points of the M, allowing the whole thing to be secured to the mast when not needed. Then, when lowering the sail we'd hook them back up. I don't have a sail cover designed for lazy jacks, so I need to move them out of the way anyway. I'm leaning toward 1/4". 3/8" seems like it could be bulky in that application.

 

[Hollyberry]

Storing them off the mast is much quieter (think halyard slap x 3)
Fresh 1/4” will be fine but you may find you’ll have to replace them periodically.

 

[Justin_NSA]

Take a look at Sail Care's Sail Cradle. Sounds like what you want to do

Sail Cradle MK IV – Sail Care

sailcare.com