Saturday, 1 February 2014

Modifying the sails - Part 2

After my previous entry on our motivations, here is an update on the work we have done so far modifying our sails for hanks.

Unpicking the old stiching

The sails we have are fitted with boltropes for the luff foil. There are 3 ropes sewed into the luff of each sail. As the grommets to take the new hanks have to be at the very leading edge of the sail, that means two of the ropes had to be removed.

Tired after the first sail. 7 to go...

To remove the ropes means unpicking every stitch along the length of the luff (about 10m). The sails were well put together, so there was a line of stitching through each of the two ropes, another between them and a fourth behind them. That means, for every sail, going along the length of the sail with a small knife individually cutting each stich, four times. Every tiny piece of thread ended up on my floor. My Fitz accomodation means having a cleaner hoover my room each Thursday is mandatory. For the last three weeks, she has been somewhat perplexed by the huge amount of thread all over my floor.

Piles of this cover my entire floor...

Opening the luff

With the threads removed we cut as close to the remaining bolt rope as we dared, opening a flap of single layer dacron at the leading edge of the sail. At this point the sails are as good as useless. No turning back now!

The opened flap. The stiching on the right is the remaining boltrope


We knew we would need a sewing maching to repair our newly destroyed sails. It took us a while debating the choices before we came up with a hand cranked 1980's beast that cost £200. It is a well built bit of kit, with substantial iron gearing - sold as semi-industrial and able to sew leather. We chose it for several reasons. A hand cranked machine will allow emergency repairs to torn sails anywhere in the world, reassuring for ocean crossings. Assuming we get good at sail repair, we may even make a bit of pocket money sewing other people's sails in remote ports! Secondly, it was one of the few hand cranked machines available able to do zig-zag stiching - prefered by sailmakers. Despite being sold as refurbished Igor and I had to spend a few hours when it arrived reworking several parts of the mechanism to make it work.

With a bit of practice, it seems to work well, and the newly sewed luffs certainly look professional. At the highly reinforced areas, like the head and tack the machine won't puncture the sail. I'm not surprised. I have sewed these reinforced areas by hand, they often require your full body weight behind the needle.

Punching the new grommets

With our new holepunch we will be able to punch a series of holes for the new grommets. We haven't gotten to that stage yet. We are waiting until all the luffs are done before we take all the sails to somewhere big enough to spread them out. We need to measure and mark exactly where we want the hanks. Definitely not my room, a squash court or sports hall seems plausible.

Pulling out one of the old grommits

In the meantime, we have been experimenting with some of the sails that already had grommets. The old metal rings are heavily corroded and easily pulled out. The new grommets were sucessfully punched in. They come as two halves that slot nicely together. A wedge fits in the middle, and rests on a die. A little heavy hammering splays the steel of the inner ring which bites into the outer ring (apologies to my housemates). As with the sewing, the results look very professional and we are very happy with what we are producing.

The die, and two of the new grommets

Adding the hanks

We initially sought a quote to have a professional do all the work. The charge was astronomical and we were quite put off. It turns out most of the cost was for new hanks, which retail for ~ £15. With nearly 15 hanks per sail and 8 sails, we were looking at around £2000. Investing half the cost of the boat in hanks seemed ludicrous. Fortunately Igor located alternative "knock off" equivalents for less than £3 each. Some would say saving money on such an important piece of the boat is a foolish false economy. To be honest, a hank is simply a steel hook. It is hard to see how anyone justifies the higher cost of the "real" hanks...

Two halves of a grommit, a plastic luff protector and an unused hank

Fitting these hanks into the sail is a bit of a game. The video shows the first going in. I hope they'll get easier. Essentially there is an open "gate" with a thin arm. The arm goes through the sail and after some hammering bends round to close the gap. Simple in theory, but bending stainless steel is a bit of a chore.

To summarise

This has been a big job. It goes on. To recap, each sail needs unstiching along the length (almost done), cutting, folding and re-sewing (one sail done), holes punched and grommets placed (waiting to be measured) and finally hanks added.

As you see, lots of work to be done, but we need something to keep us busy when it is too cold for epoxying on the boat, and with some more dedicated evenings we will get there soon!

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