Hi
I'm having an awful time rigging a new 10m cammed race sail for the first time. This is my first cam sail. It's on a matching 550 mast but I can't get the cams nearest the boom to stay on the mast. I have experimented with a variety of downhaul/outhaul tensions but the cams pop off the mast. The mast is made by the same manufacturer as the sail and they only make SDM masts for that size sail so it can't be that the cams are for a skinny mast. I feel like I have the downhaul correct because the triple pulleys on the sail are lined up with the mast length numbers on the extension. However, at this tension, the mast has not bent sufficiently to fill the leading edge of the luff pocket. Should the downhaul tension cause this to happen? I'm using a screw driver and my foot on the end of the mast extension to apply tension. Is this enough? Everything I read says I need more tension. How do you know when you've got this right? Any help would be most welcome. I've spent a couple of frustrating hours on this now and have so far have only managed to get blood stains from my hands on my sails.
Cheers, Hoadles

I suspect that your extension starts at 4cm or something like many do and you are not getting pulley to pulley contact so you are 4 - 8cm too short on the downhaul...?

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Mark _australia said..
I suspect that your extension starts at 4cm or something like many do and you are not getting pulley to pulley contact so you are 4 - 8cm too short on the downhaul...?

Thanks for your quick reply.
OK - that could be it - so another vote for more tension. Should the mast bend to fill the luff pocket?

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Hoadles said..

Mark _australia said..
I suspect that your extension starts at 4cm or something like many do and you are not getting pulley to pulley contact so you are 4 - 8cm too short on the downhaul...?

Thanks for your quick reply.
OK - that could be it - so another vote for more tension. Should the mast bend to fill the luff pocket?

If the mast contacts the luff pocket all the way down, before the cambers are on, you'll have a very flat sail! The cambers are there to force, this "excess luff curve" back into the sail, creating the draft. But, when the cambers are in place, there shouldn't be any loose luff pocket in front of the mast. Some sails come with shims/spacers to insert between camber inducer and sail, to take up any slack there.

^^ +1

and I think we need pics

Pretty sure you don't have enough downhaul. And you even said that you have tried with different outhaul settings aswell, so it must be not enough downhaul.

Also downhauling a 10 m sail by hand is very hard, for big sails I use a crank

Couple of observations from my experience:

If the top cam is also refusing to latch on to the mast, then it is most certainly insufficient downhaul. In my sails, minimual downhaul gets the bottom cam on. A bit more downhaul and the second cam up will stick. More DH again and the third cam will stay and so forth. Pretty much the reverse when de-rigging - my cams all pop off the mast in sequence top to bottom as downhaul is let off. You only advised about the two cams near the boom, but if the bottom cam is staying on, then downhaul is your answer.

You would need everything going in your favour to downhaul a 10m sail by hand (formuline rope, nice big smooth pulleys on sail and mast base, sound technique and big muscles). A winch makes things soooo much easier and safer. I must post a picture of my beastie downhaul winch - like nothing you've ever seen before!

I run most of my mast bases at 4-6cm of additional extension over what the nominal figure is (eg for a 470cm luff on a 460 mast, I'll be running that base at 14 or 16 cm, not the 10 cm that the strict mathematics would dictate). Not sure why this is the case but it's reasonably consistent across all my sails including the ones where there are manufacturer markings on the sail to indicate when sufficient downhaul is set.

Good luck. Eckas

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Hoadles said..
I feel like I have the downhaul correct because the triple pulleys on the sail are lined up with the mast length numbers on the extension.

Hmmm.... Here's where a pic might help because it reads like you are setting the extension too long and then downhauling to the marking for the correct extension length.

You set the length of the extension to the correct length first. In this picture the first one on the left is set to what appears to be 6cm, and the second on the right is set to 18cm.



The mast will stop at the black thingy giving you an overall mast + extension of the correct length for luff.
Then you downhaul all the way to the bottom, like this:



^ This guy still has about 2-4cm to go.

Note that the specified numbers for extension lengths are a guide. On my sails I've found they rig best if i set it 2cm less, for example.

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I'm using a screw driver and my foot on the end of the mast extension to apply tension.

NO! God no! Do not use a screw-driver!

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I've spent a couple of frustrating hours on this now and have so far have only managed to get blood stains from my hands on my sails.

This is why you do not use anything sharp. FFS man your balls are there and you're putting on a lot of tension with a sharp object.

I use the harness for my wave sails but for a 10m sail, which is seriously ****ing massive, I don't think it's enough. I think you need a winch. I've never rigged anything that big.

Do you realise that for cammed sails it is best to apply half the downhaul, then lots of out haul. Then pop the cams on and after the cams are on downhaul the rest of the way?

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Windxtasy said..
Do you realise that for cammed sails it is best to apply half the downhaul, then lots of out haul. Then pop the cams on and after the cams are on downhaul the rest of the way?

I started in those days when we had Dacron and Mylar films. The correct way to rig was to apply moderate downhaul to set the sail. Lots of outhaul almost to the point of flatening the sail, was then applied to bent the mast, then full downhaull tension. The theory was that once the mast is bent, it becomes easier to apply the downhaul.

Old habits die hard...I still do it nowadays, even with the modern sails.

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Jupiter said..
I started in those days when we had Dacron and Mylar films.

I started with monofilm and moved to dacron.

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evlPanda said..

Jupiter said..
I started in those days when we had Dacron and Mylar films.

I started with monofilm and moved to dacron.

I started with animal hide and moved to hessian

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2035 said..

evlPanda said..

Jupiter said..
I started in those days when we had Dacron and Mylar films.

I started with monofilm and moved to dacron.

I started with animal hide and moved to hessian

Well we had it tough...

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seebreez said..
Pretty sure you don't have enough downhaul. And you even said that you have tried with different outhaul settings aswell, so it must be not enough downhaul.

Thanks - I'm getting the picture. More downhaul!

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evlPanda said..

Hoadles said..
I feel like I have the downhaul correct because the triple pulleys on the sail are lined up with the mast length numbers on the extension.

Hmmm.... Here's where a pic might help because it reads like you are setting the extension too long and then downhauling to the marking for the correct extension length.

You set the length of the extension to the correct length first. In this picture the first one on the left is set to what appears to be 6cm, and the second on the right is set to 18cm.



The mast will stop at the black thingy giving you an overall mast + extension of the correct length for luff.
Then you downhaul all the way to the bottom, like this:



^ This guy still has about 2-4cm to go.

Note that the specified numbers for extension lengths are a guide. On my sails I've found they rig best if i set it 2cm less, for example.

I'm using a screw driver and my foot on the end of the mast extension to apply tension.

NO! God no! Do not use a screw-driver!

I've spent a couple of frustrating hours on this now and have so far have only managed to get blood stains from my hands on my sails.

This is why you do not use anything sharp. FFS man your balls are there and you're putting on a lot of tension with a sharp object.

I use the harness for my wave sails but for a 10m sail, which is seriously ****ing massive, I don't think it's enough. I think you need a winch. I've never rigged anything that big.

That's really helpful. No - I haven't got to the point where the pulleys are all the way down so - yes - I really need a winch to go the whole away. You guys have been a great help, thanks.

for downhaul - you can put a loop on a wood piece like in the photo to start
i did not see sail brand and model discussed
thought most 10-ohs rigged on 520s ??

for loop - it is at about 1:19

Try sliding the mast into the luff pocket but not in the cams first. Downhaul the sail. Put the boom on at recommended lenght. Release the downhaul. Push downward force on the batten which relates to the cam you are fitting, (This will push the cam downward and make it easy to lock onto the mast.) Repeat for each cam. Then complete the downhaul. Again..... Not with a screw driver!!!!! Use your harness hook or a rig winch. Also would be good to know what brand/ modle sail as some brands have their different querks when it comes to rigging.

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moondo said..
Try sliding the mast into the luff pocket but not in the cams first. Downhaul the sail. Put the boom on at recommended lenght. Release the downhaul. Push downward force on the batten which relates to the cam you are fitting, (This will push the cam downward and make it easy to lock onto the mast.) Repeat for each cam. Then complete the downhaul. Again..... Not with a screw driver!!!!! Use your harness hook or a rig winch. Also would be good to know what brand/ modle sail as some brands have their different querks when it comes to rigging.

Make sure the mast is OVER the cams...then you can push down later to get them on..Don't risk your back - get a whinch!

Never use anything sharp to downhaul with. If the rope snaps you'll stick yourself. Nobody looks good with a screwdriver sticking into them.