Saturday, 1 February 2014

Modifying the sails - Part 1

Why are we modifying the sails?

While the weather has been too cold and wet to work on the boat we have been spending our time stiching, unpicking, sewing and hammering our sails. This was quite a large job, and, once started offered no chance to go back! In short, it seems plausible you may be wondering why we are doing this?

Different types of forestay attachment

The following introduction is something of a basic guide to sails and how they are attached to the forestay. For those readers who know a bit about sails skip this part and go to the next section, about our motivations for replacing the luff groove system we had with hanks.

Head sail, foresail, jib, genoa and staysail are names for the various sails that are hoisted in front of a mast. The name often depends on technical details about the shape or position.

Whatever the name, the entire leading edge: the luff, must somehow be tied along its whole length to a wire, the forestay, running down from the top of the mast to the deck:

Diagramatic depiction of a luff attachment

There are several solutions to this problem. The first is a thick bolt rope built into the luff of the sail which slides up a groove, or foil. This is what we had on Auriga when we bought her, and what got her home from Spain. The second is a series of hooks built into the luff of the sail (known as hanks) which clip directly onto the wire. This is what we want.

Left: Luff foil system on Kestrel      Right: A single hank. A jib will have one every 1/2 meter or so.

Thr problem with either system is that when the wind gets up and you want less sail area, you have to take down the headsail you have, and replace it with a smaller one. This can be arduous, as you have to spend some time getting wet on the foredeck. The other option is a furling sail: a peice of kit that roles the entire sail around the forestay. Sounds good, but it makes the boat rubbish. Also, what are we, a 70 year old retired couple? In my mind you don't go to sea if you can't put up with getting wet. Suffice to say, this idea was not considered.
This article explains some of the reasons against furling head sails:

So why Change?

When we bought the boat it came with a good collection of headsails (8!) and a decent aluminium luff foil fitted to the forestay. So why change the system we have?

Firstly, the luff groove we have is 10-20 years old. If it were to break at sea we would be left with no usable headsail. If a hanked sail breaks, we could change to another and continue on our way. So the first reason is one of reliability. With the current system we rely totaly on one peice of equipment, and suffer the consequences if it breaks.

With that in mind, we would likely want to replace the old luff foil whatever happens. Consider also, that to inspect the quality of the forestay we would probably have to destructively remove the old equipment anyway. As we were looking at an expensive repare whatever we chose the investment in upgrading the sail wardrobe for hanks was offset somewhat.

The next point is one of sail handling. When a luff groove headsail is dropped, the bottom comes out of the groove. That means the entire mass of sail is held on only by the tack and clew. This quickly becomes difficult to handle by one person on the foredeck in strong winds. With hanks, the luff of the sail stays attached to the forestay even when dropped. Think of the pictures of old sailing ships and their jibs bundled up on deck:

Neatly bundled jibs on an old ship

We are now well on our way to adding hanks to all our sails. We have had to unstick the sails, acquire a sweing machine, learn to sew, learn to add grommets (metal rings) and find affordable hanks. I will write a new entry soon with pictures of all this work.

1 comment:

  1. Fascinating stuff there. Seems like a lot of work, but I agree with you in that it's better to change them now than be caught out at sea and have to deal with them breaking and leaving you stranded. I trust you'll get the hanks on without a problem; you definitely seem to know what you're doing. Thanks for the information.

    Steve Burgess @ Atlanta Yacht Sales