I have a rigging question...

[John N]

On the right is how I have seen it done so I guess it is the correct way but I'm wondering if I can do it how it is on the left. It means the block up on the mast would be twisted slightly. Is that a problem? It would seem to me that there is less friction and a more direct pull using just the one block on the deck? The yard being raised weighs 12 lbs. It is for the boat I'm building on this thread
http://forum.woodenboat.com/showthre...very-slowly%29

[John B]

The thing is , is that when you do that you're effectively making that halyard into a kind of shroud and it biases the structure of the mast to some extent. So when you do that its nice to have one on the other side doing the same. Topping lifts on a traditional gaff boat are like that for example.

Then the other thing that happens is that there's always flex in a mast/rig to some extent. That halyard will ease slightly on port tack and tighten slightly on stbd. Cumulatively that could have quite an effect on sail trim port to stbd tacks. Having said all that you can see boats with halyards out to pin rails on the shrouds/ gunwhales, but I don't subscribe to the practise.

[Chip-skiff]

I had the same idea, for a double-ended mainsheet on a leg-of-mutton sail. Because the boom stays on the same side of the mast and on a run, the sail out to starboard would interfere with the mainsheet. So it had to be kept close to the mast.



There's a wee block lashed to the boom, that can be moved. As the boom tracks back and forth, the swivel block on the base of the mast adjusts to the varying angles. I added a spring to keep it from flopping and fouling. Works a treat, so far.

Here's a source for the block:

http://www.duckworksbbs.com/hardware...l306/index.htm



If you've got a round mast, you'll have to engineer a flat base.

[John N]

Thanks for the replies.

you're effectively making that halyard into a kind of shroud

That's what I didn't see, and in reality there are three halyards, throat, yard and jib. I was going to route the jib to the other side anyway but still I can see it is better to have them pull straight down.

[wizbang 13]

A 12' yard, you say. D'you mean a gaff/ gunter? This is for the gunter haliard?

[Thorne]

Halyards run out to the side also interfere with access to and past the mast, sail raising/lowering, etc.

[ramillett]

John The problem I see with "A" is you are trying to left the deck up with a 2 to 1 purchase , on "B" the first block just put the mast in compression , and the second block the force is in shear on the deck . On my boat there is a 3/4" tie rod connected from the mast step to the deck to prevent the deck from lifting . Bob

[John N]

you are trying to left the deck up with a 2 to 1 purchase

Another good point. Well, there is no question which way I'll go. I just had to know why.

Thank you ,
John

[wizbang 13]

2 to 1 purchase? Where is that?
A rod from the step to the deck is to keep the deck from crushing, not lifting.

[Ian McColgin]

First - ALWAYS halyards that handle stuff abaft the mast come down to starboard while halyards that handle stuff ahead of the mast come down to port.

Second - halyards that handle stuff higher on the mast go outboard of halyards that handle stuff inboard. If you happen to be leading the halyards all the way to the rail, as I did foremast’s halyards on the schooner Goblin since I had nice pin rails on the stays, then the higher halyard goes abaft the lower. One look at how to make clean runs will reveal the logic of this.

In general, it’s best to have the halyards terminate where the fall approaches the deck - a cleat or cleat and winch on the mast, at the mast base, or out on a pin rail. However there are boats where for safety or other utility you should run the halyard aft to the cockpit. Which brings us to your drawings.

The proposal, just one block, is vastly vastly vastly better from an efficiency and ease of handling perspective. Each turning block adds both friction and, do a parallelogram of force, inefficiency. The only reason for turning blocks is if you absolutely must to direct the line.

If the sense of perspective I read in is right, I think the one halyard you drew is too far aft. Move them (peak and spar) out really abeam of the mast.

There are a number of advantages to placing the halyards off to the side and some potential disadvantages. If led to the side, you have no slap, which on some points of sail and some winds can take the paint right off a mast. You also have a cleaner air flow separating the air turbulence around the halyards from the turbulence around the mast, though I think this a minor consideration. If you care about that level of efficiency, you need halyards in the mast and a profoundly different sort of rig.

The halyards should be located such that they do not bear on the sail’s luff. The further outboard you go, the more directly abeam, not abaft at all, the mast your lead must be. This is no problem for the halyard blocks if you hang them such that the shiv is athwartships. The block’s cheek may lie against the mast and you may want to leather it to protect the mast. This can always be done with a throat halyard.

Sometimes the lead off a peak or spar halyard is such that the block’s shiv must be fore and aft. If this is the case and if however you hang the block does not leave it swinging clear, add a bit to the cheeks along the rim that will bear on the mast both to cushion everything and to prevent the halyard from bearing on the mast.

Marmalade’s gaff and sail make way too much weight, even with our 4:1 tackles, to use a turning block. The lead down to the deck is about 6” away from the mast. I’d like to go further out but can’t then get a fair lead over the coach and back. In the picture below, the two vertical lines visually just ahead of the Buzzards Bay 14 ahead to starboard are the throat and peak. They come back to the two cleats in the foreground. I hang both coils on the LazyLift cleat further outboard so that they don’t obstruct my view of the depth sounder.

To clear the front of the coach, the double block is on a strap. Under load it angles back at forty five degrees. A bit of clear plastic hose sheathed in leather for the looks is over the strap and deck eye below and block eye above, pushing against the deck below and block above, thus keeping the thing from falling on the deck when slack.

G’luck

[Wooden Boat Fittings]

... in reality there are three halyards, throat, yard and jib. I was going to route the jib to the other side anyway but still I can see it is better to have them pull straight down.

I understand that your vessel is to be fitted with shrouds, so in your case this next point is irrelevant. But in some otherwise-unstayed rigs halyards can indeed be used as pseudo-shrouds. My open fifteen-foot sloop was rigged in just this way -- the main halyard was taken to a belaying out on the starboard end of the sailing thwart next to the inwale, while the jib halyard was rigged the same way to port. (Sail areas were about 100 sq ft and 20 sq ft respectively.)

Mike

[SchoonerRat]

2 to 1 purchase? Where is that?
A rod from the step to the deck is to keep the deck from crushing, not lifting.

It's my understanding that a post beneath a deck stepped mast is to keep the deck from crushing but if the mast is keel stepped, a tension rod needs to be installed to keep the deck from lifting due to shrouds and stays pulling the ends of the boat together.

[Gold Rock]

The only other caveat I haven't heard mentioned may not apply here as this sounds like the peak or throat haliard on a gaffer, which probably turns through a free swinging block, but for all others considering this idea in general, also remember that if the haliard turns over a sheave riding in a sheave box let into the mast, offsetting the angle of pull dramtically will generate mucho very undesirable chafe and friction.

[wizbang 13]

It's my understanding that a post beneath a deck stepped mast is to keep the deck from crushing but if the mast is keel stepped, a tension rod needs to be installed to keep the deck from lifting due to shrouds and stays pulling the ends of the boat together.

Oh OK, I gotcha. It's a rod going out to the clamp/sheer. I pictured it going straight up.
But I hope the fella does not need that on this wee boat, sounds like something on a high strung racer?

[wizbang 13]

The only other caveat I haven't heard mentioned may not apply here as this sounds like the peak or throat haliard on a gaffer, which probably turns through a free swinging block, but for all others considering this idea in general, also remember that if the haliard turns over a sheave riding in a sheave box let into the mast, offsetting the angle of pull dramtically will generate mucho very undesirable chafe and friction.

Crikeys thats right too! So, what is aloft, and why are you thinking of doing this mod. anyway?

[Ian McColgin]

You can tell that the mast designer is a competent rigger rather than a farmer on loan from making street light poles if the shiv box that has two shivs, one for jib and one for main, is angled a bit to starboard, putting the front edge of the port shiv on center and the aft edge of the starboard shiv on center. Sadly, almost all production boats have masts designed by farmers. But as was pointed out above, it's unlikely that a gaff rig has a masthead shiv box.

[John N]

Wow, a lot of information, thanks again.
The throat and yard blocks are free swinging so no problem there. I did let a sheave into the mast which I was planning on using for the jib halyard. In that case I would need a turning block.
It a gunter rig btw.

If the sense of perspective I read in is right, I think the one halyard you drew is too far aft.

That's just crappy drawing skills. I understand what you mean.
The mast is deck mounted on a tabernacle with a post going to the keel beneath it.

I just wonder if the pull on the deck would be a problem? The plans show only a single block set up but I plan to use a double on both throat and yard.

The proposal, just one block, is vastly vastly vastly better from an efficiency and ease of handling perspective. Each turning block adds both friction and, do a parallelogram of force, inefficiency.

This was my original thought. I have no experience with a rig with a yard. I just thought in my mind that it seemed pretty heavy and eliminating turns and blocks made sense.
Still not sure about the pull on the deck though...
Confused as usual. Have to think some more, I guess.

[Smacksman]

That was going to be my point - the strength of the deck to take the pull from a halyard. That is why they are normally close to the mast or taken to cavil rails by the shrouds as in a smack - both places are strong points.

[SchoonerRat]

Oh OK, I gotcha. It's a rod going out to the clamp/sheer. I pictured it going straight up.
But I hope the fella does not need that on this wee boat, sounds like something on a high strung racer?

Actually, the tension rod does go straight up. It is bolted to the deck, and to the mast step. Most of the pull on the chainplates is up, but there is a component of force trying to pull the chainplates towards the centerline of the boat. This has the effect of trying to raise the cambered deck - kind of a bow and arrow effect. With a keel stepped mast, there is no need for additional compression support. To be honest, I don't recall seeing a tension rod on a woodie. High strung racers generally have a "cage" built that all but completely isolates the rig tension from the hull and deck.

[Ian McColgin]

Just how much stress do you think the halyards provide? If you can stand on the deck , just through-bolt and back the deck blocks and you'll be fine.

[Chip-skiff]

What's lacking is a description of your craft. The larger it is, the greater the potential forces involved. And greater consequences for getting it wrong.

[Gold Rock]

Just how much stress do you think the halyards provide? If you can stand on the deck , just through-bolt and back the deck blocks and you'll be fine.

Agreed. This isn't a cap shroud. Unless your cabin top is made out of paper mache, normal haliard tensions shouldn't have any adverse affect on the vessel's structural integrity as long as you follow Ian's common sense guidelines. The only downside to your whole proposal I can see is that the resulting new location of the haliard would, in my opinon, compromise access to the mast base in particular and fore and aft movement along the vessel's length in general. As mentioned above, if you do want the haliard routed away from the base of the mast, route it all the way to the rails vis a vis a pin rail.

[Wooden Boat Fittings]

What's lacking is a description of your craft.

John is building a 'Wee Seal,' as he says in his first post. This thread has details, with a drawing at Post #7.

Mike