Over the summer I injured my hand pulling the sail up. I’ve got an old trigger-finger injury and the high load on the halyard meant that this re-occurred: one finger couldn’t be straightened for a week or so. This is irriating rather than a big issue but I don’t want it to get worse. Thus I clearly need to sort the halyard load out.
The sail bundle weighs around 9kg. This is quite a lot to be swinging around at the top of the mast but doesn’t seem to make any difference to boat stability – probably because the sail also stabilises the boat. However any weight reduction would be a Good Thing.
The heaviest parts of the sail are the yard and battens. On my two boats the battens and yard are as follows:
|Item||Section||Weight kg/m||Yield moment Nm|
|Owl yard||1 1/4″ x 16swg||.42||277|
|Owl batten||5/8″ x 18swg||.15||68|
|Cust. yard||2″ x 16swg||.68||509|
|Cust. batten||1″ x 18swg||.25||91|
There are 6 battens on Custard and 5 on Owl. The battens have a much greater influence on overall weight due to the number of them.
The actual weights of the spars is slightly different to the nominal figures above. In my tests the yard weight is spot-on but the battens are actually slightly lighter per meter (about the same as 7/8″ tubes .22kg/m) – I think they have thinner wall thickness than specified.
The total for the metal tubes in the sail is around 6.3kg – the rest of the sail weighs around 3kg, despite the very thin sail cloth. This does seem a lot – probably most of this is the reinforcing tape at the luff and leach of each panel. If anyone out there can weigh the standard sails for a Wanderer I’d be very interested to know the figures.
Testing the tubes (trying to bend them by hand) I would say that:
- The Custard spars are stiff enough;
- The Owl yard is plenty stiff enough, both for Owl and probably for Custard, although on Custard it should probably be a slightly bigger section;
- The Owl battens are a bit bendy – fine on the low loads on the Owl sail but might cause issues on Custard.
This is highly subjective – it is very hard to know whether this is right! I’d only know I’d got it wrong if the spars broke or I had issues relating to battens bending too much.
Looking at the figures from the Properties of Tubes page I think that the Custard spars could get thinner – maybe down to 1 1/2″ x 16swg for the yard. This wouldn’t save much weight – maybe 500g which won’t make much difference to pulling the sail up but would be beneficial to boat stability.
The Owl sail is easy to pull up. Overall weight is around 5.3kg. The halyard is a straight pull over a pulley at the top of the mast and down to the yard – no mechanical advantage.
Custard’s sail has a 2:1 mechanical advantage in the halyard. Given that the sail is less than 2x heavier than Owl’s it should be easy to pull up. So there is a problem somewhere else.
One possible solution would be to increase the mechanical advantage to 3:1. The downsides would be:
- It looks like the problem is actually elsewhere so it might not fix the problem;
- I’d have a lot more string to manage
The halyard is cleated on a board mounted to the back of the centreboard case. This is low down in the boat and is close to other lines. There isn’t a direct pull on the line and this makes it much harder to pull the line and get it cleated ok.
I could route the halyard onto a separate cleat under the thwart. This would be much higher up and thus much easier to pull.
I think the real issue is too much friction in the system. There are various candidates:
- Halyard crane at the top of the mast;
- Ultra-short batten parrels;
- Grommets where the line goes through the deck or onto the cleat board;
- Mast foot turning block (home made);
- Barton blocks on the yard and mast top.
Of these I think the two most likely candidates for further investigation are the halyard crane and the batten parrels.
The mast head halyard crane is just a loop fitting screwed to the mast. There isn’t any stand-off from the mast and others have reported that this means the halyard rubs on the mast. I’ve checked this without the sail in place and there is no rubbing; however with the sail in place the halyard may rub on the batten parrels.
The ultra-short batten parrels seem to work surprisingly well. They are a bit harder to rig than the rucksack clip parrels on Owl; otherwise they are ok. If too tight then the sail can need help to come down and it is this that leads me to suspect they are also making it harder to pull the sail up.
There are a few things that are worth doing. First job is make some longer batten parrels. This should reduce friction and maybe will make the sail faster to rig and remove. I will need to remove the jiblet panel from the battens and sew on some tape but this is straightforward.
Once the batten parrels are sorted properly I’ll be able to make a judgement on how long the halyard crane should be.
I’ll take a look at putting the halyard cleat on the underside of the thwart to improve the angle of pull.
It is probably worth getting a smaller tube for the yard to reduce the weight aloft. Main issue here is the delivery cost of the single tube.
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