Mainsail tack attachment

[chris-s]

I’m wondering what the intended method of attaching the mainsail tack to the boom/mast is on our new-to-us OC320. When we acquired the boat the sails were off and there was a long dee shackle on one of the rings as shown in the photo. Clearly this is not the correct way to attach the sail as it holds the tack ring at the wrong angle (not that it makes much difference given the state of the sail), at the very least, a twisted shackle would be better or should it just be tied-off?

Whilst we are here, the reef tack points I assume are just intended to be tied-off to one of the rings on the mast?

I'll shortly be ordering a new main, so if there is anything I could do to improve this setup (which might affect 'tack-cut back'), then let me know. I'd like to fit some 'reefing horns' somehow too.



Chris

 

[VicS]

Id expect t o see the tack secured to the boom or to the goose neck.

Perhaps replace the bolt through the goose neck with a ring bolt and shackle the tack to that ???
Even
Combine the rams horns with the eyebolt in some purpose made fitting ???

Have a wander round the marina to see how its done on other boats

 

[Poignard]

 

[chris-s]

View attachment 156903

Yes, that’s the sort of thing. I just can’t figure out how Beneteau had intended for it to be attached….unless of course the gooseneck pin/bolt was changed at some point.

I’m not sure a typical eye bolt would be a good option as they tend to be a machine screw rather than a bolt and so the threads would be bearing the loads/swivel action and wear the gooseneck?

 

[KevinV]

If you put the shackle through one eye, through the sail and fixed in the other eye the orientation would be correct.

 

[Poignard]

[...]

I’m not sure a typical eye bolt would be a good option as they tend to be a machine screw rather than a bolt and so the threads would be bearing the loads/swivel action and wear the gooseneck?

That's a very good point and I would certainly not use a threaded-to-head bolt in that situation.

But what you see there is a proper goose-neck pivot bolt that originally had two horns loosely rivetted to the top. I removed these horns and that left what you see there, a sort of eye-bolt, to which I shackle the tack of the sail.

Before removal of the horrns:

 

[chris-s]

Right, after a bit of googling, I have determined that it is an Isomat spar setup and those rings on the mast are part of the auto-reefing feature...



... so at least I have something to go on. Oh, and the reefing blocks inside the boom are long gone.

Chris

 

[Refueler]

You don't have to use a shackle - you can use a light line passed through multiple times to secure ... using both mast eyes and sail tack.

 

[Chiara’s slave]

You don't have to use a shackle - you can use a light line passed through multiple times to secure ... using both mast eyes and sail tack.

Or a soft shackle if the mood takes you. The twist wouldn’t be as important then.

 

[Refueler]

Or a soft shackle if the mood takes you. The twist wouldn’t be as important then.

Lets be honest - many boats have a shackle at gooseneck ... then a light line reeved through clew to secure at boom end ...

 

[Chiara’s slave]

Lets be honest - many boats have a shackle at gooseneck ... then a light line reeved through clew to secure at boom end ...

They do. Neither of my boats but I accept it’s common practise, and entirely satisfactory on many boats

 

[chris-s]

You don't have to use a shackle - you can use a light line passed through multiple times to secure ... using both mast eyes and sail tack.

Yes, absolutely. I was thrown by the existing Dee shackle and lack of understanding how it had been intended to be used.

 

[Poignard]

Here’s a simple, secure system using lengths of Dyneema and snap shackles.

 

[chris-s]

Looks like I have worked out how it was intended to be used. From the spare parts page it seems as tho the pin should be fitted the other way around and a shackle fitted thru the hole…



Mystery solved!

Chris

 

[Martin&Rene]

On your new main, consider having pulleys put in where appropriate. This thread describes parts of my single line reefing system.

Single Line 3rd Reefing Setup

It is good not having to go to the mast whenyou are reefing the main.

 

[chris-s]

On your new main, consider having pulleys put in where appropriate. This thread describes parts of my single line reefing system.

Single Line 3rd Reefing Setup

It is good not having to go to the mast whenyou are reefing the main.

There are some good tips there. The existing sail has three reefing points, it’s recognised that this boat is over-canvassed and we will include three on the new sail. Out of the factory it was only setup for two reefs so doesn’t really have the boom fittings for a third. In a previous life it has been to the Caribbean and back so it’s plausible that a new sail was commissioned with the extra reef point at that time. It definitely looks like it’s seen some miles!

 

[William_H]

Glad OP has figured out the tack atachment. Essentially the tack should be close enough to the mast to take luff in a straight line from tack up to head attachment without loading the luff slugs or blot rope. Similarly but not so important with loose footed main the tack eyelet should be close to the boom. if you have a bolt rope mnina track on top of boom it is even more important get tack eyelet down close to boom. Of course it is possible that tack eyelet has been fitted further in to sail to allow for a long shackle to gooseneck but still have luff in line.
So when we get to a reef it is similarly desirable to get the reef tack eyelet up close top the mast. (and boom but less so )
I use a similar system at the reef tack to Poignard in his lovely picture except the front reefing line is permanently attached and runs from the saddle on one side below and forward of gooseneck up to eyelet then back down to a similar saddle on other side (or cheek block) then dowen to turning block on deck back to a winch. The location of the saddles approx. 45 degrees down from where the eyelet will sit when reefed gives an equal pull forward and down. But gets the eyelet tucked in close to mast and boom. I can reef in seconds while hard on wind from cockpit. Gaskets (ties around bunt of spare sail) are optional.
So I would argue against using ram's horns or single line reefing, go for 2 line reefing from cockpit. Much safer albeit a bit messy with lots (6) of lines if you have 3 reefs. ol'will