Mainsail halyard connection points

[dmksails]

My mainsail has 2 places for attaching the halyard. Can someone tell me why and which one should I use?

Boat is a Tashiba-31

[steve77]

I have always used the one closest to the mast. On our boat it gives a good lead for hoisting the mainsail. In case of failure of this headboard grommet, the second one is a serviceable backup.

Cheers!

Steve

[SVHarmonie]

I asked this question many times over the years, of all kinds of people who I expected to have a good answer for me. More experienced sailors, sailmakers, etc. They either didn't know, or gave an answer that made no sense. Until...

I was teaching an advanced sailing class, and somebody in the class asked the question. I said I didn't know. One of the young ladies in class said, "My Dad was a sailboat rigger for 30 years. I know."

Here was the answer she gave, and it has the advantage that it makes sense. Might even be right...

Older sails with stretched out leeches have trouble with keeping proper leech tension. Using the aft hole tensions the leech more, and helps control leech flutter. Most of this rational has gone away with modern sail materials and design, so it as actually a case of they always looked like this, so they still do.

[sanibel sailor]

I have wondered the same thing.
I always use the forward one also, because it gives the most fair lead during raising. I am not sure why there is a second hole. I doubt it is for a backup. I may be not taking into account leech loads and perhaps the aft hole is a more fair lead in use, bisecting luff and leech loads.

[barnakiel]

Some boats have external halyards while others internal ones. So the distance the sheave or block stands off creates an offset.


You can minimize this offset by moving the halyard on the headboard.

As a side dish, some systems use cars or slides attached at the top fore hole. This is not the intended use in older sail (as shown) but can be seen on modern high tech sails with long head cars.


And as noted already, when the gap is large one can get more leech tension (only just so slightly) by using the aft hole. Please note that this is much easier to achieve by trimming the leech line).



b.

[roverhi]

Internal and external halyards both pass over the same sheave on exit from the mast so no difference in angle or benefit from using either puka.

[barnakiel]

Originally Posted by roverhi

Internal and external halyards both pass over the same sheave on exit from the mast so no difference in angle or benefit from using either puka.

Rovehi


PLS expand.


Where I saw external halyards passed over a block and did not enter the mast. Internals run inside then on the sheave in the box then fall down.


On the boats I have seen external halyards (one was a BCC another was a W32), they always had more mast to halyard fall distance, exactly because of the block at the top. Internal halyards always seemed to fall closer to the mast, by maybe 2 or 4 inches on small boats (30-40 ft and thereabout). On our boat the internall halyerad fall clearance is maybe 1 inch).



b.

[wingssail]

There can be several reasons for the two holes:

One hole might line up with the halyard sheave better than the other due to the sheave placement. (the horizontal distance from the back of the mast to the back edge of the halyard sheave is a dimension which is often measured when designing a mainsail, so it can be important)

Using the aft hole puts more tension on the leach, which may change (improve) the sail shape.

In my case using the aft hole pulled the headboard closer to the mast relieving pressure on the top slugs which, because of a worn mast track, had a nasty habit of getting stuck.

[Don C L]

There are both wooden and aluminum masts that have blocks, or outboard sheaves, at the masthead because they do not run the halyards within the mast. In that case I'd use the hole farther out on the headboard. I doubt the claim that using the outer hole increases leech tension, in fact it was probably a joke. That is what a leech line is for. The only thing that will happen is you'll chafe the luff at the headboard as you raise and lower the sail. Use the innermost hole.

[roverhi]

Originally Posted by barnakiel

Rovehi
PLS expand.
Where I saw external halyards passed over a block and did not enter the mast. Internals run inside then on the sheave in the box then fall down.
On the boats I have seen external halyards (one was a BCC another was a W32), they always had more mast to halyard fall distance, exactly because of the block at the top. Internal halyards always seemed to fall closer to the mast, by maybe 2 or 4 inches on small boats (30-40 ft and thereabout). On our boat the internall halyerad fall clearance is maybe 1 inch).b.

On the common untapered aluminum masts there are two sheaves at the mast head for each halyard. The two sheaves are used to get proper fall of the halyard from the masthead for external halyards. For external halyards the line goes up outside one side of the mast, over the sheave, across to the other sheave and out the mast. That way the line falls outboard of the mast section on both sides to eliminate chafe.

To go with internal halyards, the line runs up inside the mast and over just one of the sheaves at the mast head and out. The line exits the same way as with outboard halyards and doesn't pass over the 2nd sheave. I've gained an extra halyard by running the main halyard internal freeing up the 2nd sheave at the mast head for an internal halyard. I've lost a halyard on a long passage but it turned out to be no big thing. I'd run the jib and main halyard internal over the dual blocks and moved both to the sheaves on the same side. That freed up the two sheaves on the other side to run a reserve external halyard that could double as a main or jib halyard as needed.

[barnakiel]

Originally Posted by roverhi

On the common untapered aluminum masts there are two sheaves at the mast head for each halyard. The two sheaves are used to get proper fall of the halyard from the masthead for external halyards. For external halyards the line goes up outside one side of the mast, over the sheave, across to the other sheave and out the mast. That way the line falls outboard of the mast section on both sides to eliminate chafe.


(...)

I now understand what you mean. Thanks.


I was talking about the other (third case) situation - when there is a block at the top. I have seen it on a few boats.


Halyard goes up and down on the same side of the mast. Not much used today but quite common in the past.



b.