Reefing with a sliding gooseneck

Pinning the gooseneck will result in *poorer* sail shape, and will more quickly distort a non-laminate sail material (probably also a laminate, but I don't have experience with those to say with certainty.

Simpler reefing, lower c of e, no jacklines, better sail shape.

A sliding gooseneck with an end stop has one additional step when reefing - tensioning the downhaul. But this is simpler than attempting to tension the luff with the halyard, which with the fixed gooseneck results in working further forward and pulling down, an inherently less-stable position than being aft of the mast and pulling up. Having wrestled with both at night in lousy weather, my opinion is the slider is simpler in practice despite the additional step.

The sliding gooseneck can allow a lower c of e; that was in fact part of the point of *not* switching to the fixed gooseneck.

Jacklines or not is a personal preference, not related to the gooseneck type.

And I believe you have very easy access to a sailmaker to confirm my statement regarding sail shape.

Amgine

[Brion Toss]

Originally Posted by Amgine

Pinning the gooseneck will result in *poorer* sail shape, and will more quickly distort a non-laminate sail material (probably also a laminate, but I don't have experience with those to say with certainty.

Why? What is the difference between a pinned gooseneck and one that is held fixed in place by a downhaul?

A sliding gooseneck with an end stop has one additional step when reefing - tensioning the downhaul. But this is simpler than attempting to tension the luff with the halyard, which with the fixed gooseneck results in working further forward and pulling down, an inherently less-stable position than being aft of the mast and pulling up. Having wrestled with both at night in lousy weather, my opinion is the slider is simpler in practice despite the additional step.

I think we agree here. I am just substituting a Cunningham for a downhaul. Note that I said that tensioning the halyard to tighten the luff is a bad idea.

The sliding gooseneck can allow a lower c of e; that was in fact part of the point of *not* switching to the fixed gooseneck.

It depends, of course, on the height at which you fix the gooseneck.

Jacklines or not is a personal preference, not related to the gooseneck type.

How so?

And I believe you have very easy access to a sailmaker to confirm my statement regarding sail shape.

Amgine is referring to the amazing Carol Hasse, whose shop is just upstairs from mine. And who is a big proponent of Cunninghams. But I will check with her, in case I have this one wrong. Wouldn't be the first time.
Fair leads,
Brion Toss

Exactly. The only difference is the use of the Cunningham, which is an ingenious development to modify the shape of the sail on the fly but it creates a point load within the sail.

The sliding gooseneck has the same effect, but it spreads the load into the tabling rather than from a single point. All other points being equal, the gooseneck will result in slightly better shape and considerably less distorting loads within the sail.

As for jacklines, can you explain why they would be required for a sliding gooseneck with a stop? For that matter, I removed them from my gaffer as well after adding a pair of small teak buttons in lieu of a table. There is no need for the boom to fall to the deck without halyard tension.

[Jim Fulton]

Originally Posted by Brion Toss

• Someone else mentioned tightening the main halyard as an adjunct to the downhaul. I can earnestly unrecommend this practice, as it has the unfortunate consequence of tightening the leach as well as the luff, and this is the last thing you want.

I would like more of an explanation of the distribution of forces here. As I mentioned in the earlier post, I use the flexibility offered by the sliding gooseneck to raise and lower the center of effort by raising and lowering the whole sail. When the sail is raised to the top of the mast and the gooseneck is at the top of its track, I use the downhaul to tension the luff. When the gooseneck is at the bottom of its track, I use the halyard to tension the luff. (I didn't mention thatI have boom-end sheeting, which may or may not be important.)

In the one instance, the head is fixed and the gooseneck is moved; in the other, the gooseneck is fixed and the head moves. I don't see why the effect on the sail would be different. What am I missing?

Jim Fulton

[Brion Toss]

Originally Posted by Jim Fulton

I would like more of an explanation of the distribution of forces here. As I mentioned in the earlier post, I use the flexibility offered by the sliding gooseneck to raise and lower the center of effort by raising and lowering the whole sail. When the sail is raised to the top of the mast and the gooseneck is at the top of its track, I use the downhaul to tension the luff. When the gooseneck is at the bottom of its track, I use the halyard to tension the luff. (I didn't mention thatI have boom-end sheeting, which may or may not be important.)

In the one instance, the head is fixed and the gooseneck is moved; in the other, the gooseneck is fixed and the head moves. I don't see why the effect on the sail would be different. What am I missing?

Jim Fulton

Hi,
Good question, and I think one at the heart of this discussion. When you tension the luff with the halyard, you just about unavoidably also tension the leach. How much of the halyard's effect goes to either side depends on point of sail, sheet, and vang, but you'd have to impose some very strange evolutions, like topping up the boom, to keep the leach from being affected. But when you tension the luff with a downhaul or a Cunningham, the luff is the only thing that is affected.
In addition, tensioning the halyard has a diproportionate effect on the upper part of the sail, which is relatively small; tensioning from the tack flattens the belly of the sail.
The consequences for sail shape are significant, but I don't question that tensioning the halyard works for you; in many or most circumstances there will be a net gain in performance, with a flatter sail more than compensating for some leach curl. But it ain't optimal.
Fair leads,
Brion Toss