where does my halyard cross the mast, internally?

[skyflyer]

Yes, I know, I should have thought about this and looked to see how it was threaded before I took the spreader roots out of the mast!

So, basically, 15m mast, two sets of spreaders. The masthead has two sets of sheaves, one pair leading forward for jib halyard and spinnaker halyard and one pair leading aft for main halyard and topping lift.

BUT, the entry point for the topping lift is at the front of the starboard side of the mast, and the jib halyard entry is at the aft side of the port side of the mast.

So at some point the halyard/topping lift must cross the mast - not laterally, but for and aft.

If I take this across at the wrong point the n the lines will presumably chafe against the spreader roots which of course cross the interior of the mast.

I am inclined to make the switch either between the twos eta of spreaders or between the top set and the masthead.

Anyone have any views - does it matter anyway.

(the manual is silent about this)

I guess if you threaded a halyard blind down a s tepped mast the line would fall vertically until hooked out near the bottom at the entry point, meaning the line will potentially chafe against the lower spreaders.

 

[peter2407]

My main halyard comes out of the starboard side of the mast and the spinnaker and genoa halyards come out of port slots. Mine is a selden. What is yours?

 

[VicS]

Yes, I know, I should have thought about this and looked to see how it was threaded before I took the spreader roots out of the mast!


Anyone have any views - does it matter anyway.

We need a lot more infomation, with measurements, about the geometry to suggest how the halyards should be routed past the spreaders.

(diameters of entry and exit sheves and their positions relative to the front and rear walls of the mast.)

I would guess they'd cross somewhere close to halfway if the exit points are symmetrically placed, What will that make it? between the to sets of spreaders?

I hope you have a well trained mouse.

 

[skyflyer]

My main halyard comes out of the starboard side of the mast and the spinnaker and genoa halyards come out of port slots. Mine is a selden. What is yours?

So if the spinnaker and genoa come out the port slots you have the same problem (assuming one slot is aft of the mast fore/aft centre-line). The slot that is furthest aft has to cross from behind to in front of a spreader root at some point.

My mast is US made (Isomat NG1 section). The slots are labelled at the factory with riveted on plaques.

edited to add picture of stbd side - main halyard to rear, topping lift to fore

 

[peter2407]

Not sure if i do have the **exact** same problem - I assume that the main halyard is ok, but the genny and spinny halyard slots are 1 above the other in a centre line. It may be that the genny and spinny halyards cross each other, but the main halyard goes to the right? Anyway, in what circumstances would ** I**, i.e me personally, rather than "one", a seasoned racer type, have spinny and genny up simultaneously? Unless there is an in mast routing seperation that ensures none of the above problems happen?

 

[garvellachs]

I didn't realise the "spreader roots" actually cross the inside of the mast? I thought they took the compression load round the outside? I don't think our Selden mast has any bridges inside at all? But even so, I would have thought that the "chafe" over a length of 15m is likely to be a problem assuming the inside obstruction is smooth. Also, why not re-route the lines inside the mast anyway, so that they exit in more logical positions, and just re-label some clutches?

 

[LadyInBed]

Metaphorically pull the two crossing lines tight and they will form an X crossing in the middle if they exit at the same height. If one exits a foot or so higher that the other, on a 15 mtr length it will make hardly any difference to where they cross, so if the spreader is below half the halyard height the lines will cross above the spreader, if above half the halyard height, then they will cross below.

 

[skyflyer]

Metaphorically pull the two crossing lines tight and they will form an X crossing in the middle if they exit at the same height. If one exits a foot or so higher that the other, on a 15 mtr length it will make hardly any difference to where they cross, so if the spreader is below half the halyard height the lines will cross above the spreader, if above half the halyard height, then they will cross below.

Excellent - perfect solution, thanks

 

[PaulMcC]

I think you are ignoring mast curvature - pre-bend etc. Depending on curvature you may find that the best solution is to route the lines so that they cross below the spreaders as half way up the mast they are likely to naturally sit close to the aft mast sidewall.

 

[Spyro]

I'm also wondering about spreader roots. I always thought they were rivited onto the outside of the mast.

 

[skyflyer]

I'm also wondering about spreader roots. I always thought they were rivited onto the outside of the mast.

Probably depends on the design and make of the mast. (and maybe size of boat? Mine is 32ft LWL) Mine spreader roots are solid alloy that goes through mast and sticks out about 4 inches, each side. It has 3 holes in each side, one for the stem ball of the shroud wire and two smaller are for clevis pins that keep the hollow spreader sections attached to the root.

 

[Spyro]

Probably depends on the design and make of the mast. (and maybe size of boat? Mine is 32ft LWL) Mine spreader roots are solid alloy that goes through mast and sticks out about 4 inches, each side. It has 3 holes in each side, one for the stem ball of the shroud wire and two smaller are for clevis pins that keep the hollow spreader sections attached to the root.

Interesting, thanks. Seems like quite a big hole to put in a mast at a section requiring a lot of strength.

 

[skyflyer]

Interesting, thanks. Seems like quite a big hole to put in a mast at a section requiring a lot of strength.

Surely thats exactly the point? By passing through the mast there is no compression load from the spreaders on the sidewalls of the mast?

 

[Spyro]

But it must be fixed to the mast otherwise the force would extend into the oposite shroud.

 

[skyflyer]

But it must be fixed to the mast otherwise the force would extend into the oposited shroud.

The base of the hollow spreader is tight against the mast wall - in other words the hole in the mast is big enough for the root only - so yes, there is some load on the sidewall i guess.
Not my design, obviously, and extremely common on the other side of the pond, so i guess it works. Instinctively , to me, it seems stronger than having the spreaders bearing directly on the mast al all times