470 Layout

Thread starter #41
That purchase system looks pretty nice. I can build up one of those. Both of those blocks are free-floating, correct? I like the idea of cleating the line elsewhere as well. What is the metal cable, that is affixed to the bottom block/cleat, attached to below, something on the the mast step, perhaps? What size blocks do you suppose those are? They look pretty little. Pehaps I should make a lesser system for tensioning the main halyard as well?

(Also note the blue chock in front of the mast!)
I see that, yes. Are the black things that seem to be hugging the mast also part of the chock?

Block under mast brace.jpg

I noticed this little block up under the mast brace. Is this used for the spinnaker up/downhaul mechanism?

Openings In front of the mast.jpg

This is what it looks like above. That mechanism is something I also have to rig up from scratch-none presently exists on the boat.

Blocks at the rea of the ceterboard trumk.jpg

Wondering about these blocks and the fairlead at the rear of the centerboard trunk as well.
 

LaLi

Well-Known Member
#42
That purchase system looks pretty nice. I can build up one of those. Both of those blocks are free-floating, correct?
The hook block is, the cleat block is fixed (although with a piece of wire).

What is the metal cable, that is affixed to the bottom block/cleat, attached to below, something on the the mast step, perhaps?
It's attached most likely to the mast step, yes, or to some place lower on the mast. Your mast has that mystery fitting above the vang attachment which may have been used, and might again be used for this purpose.

What size blocks do you suppose those are? They look pretty little.
The hook block is a 16 mm Harken 408, which has a safe working load of more than 300 kg, so it should be strong enough. The cleat block is a 29 mm Harken 347, which is even stronger. Carbo blocks would be somewhat out of style for your boat, though ;)

Pehaps I should make a lesser system for tensioning the main halyard as well?
Well... no. The main and jib halyards have fundamentally different functions. The main halyard is not an adjustment. It just gets the main up where it belongs, keeps it there, and that's it. You don't need to tension it and it doesn't tension anything else. That's why just a hook is sufficient.
(Did you notice on the Mackay cockpit shot (post # 30) that the jib halyard cleat is labeled "rig tension"? They're one and the same in the 470.)

Are the black things that seem to be hugging the mast also part of the chock?
No, it's a wrap-around chafe plate riveted to the mast.

I noticed this little block up under the mast brace. Is this used for the spinnaker up/downhaul mechanism?
Who knows. It's been possibly used for the downhaul or its elastic takeup. It's more likely though that the downhaul was led aft to the cockpit, through one of the blocks in front of the mast step.

That mechanism is something I also have to rig up from scratch-none presently exists on the boat.
All you need is a good hook, two lengths of thin low-stretch rope, and a piece of elastic. Pretty simple. I think that the uphaul is intended to be external, and run through the pictured block on the mast and then through the smaller fairlead. Is there a block up the mast, just above the spreaders maybe?

Wondering about these blocks and the fairlead at the rear of the centerboard trunk as well.
Didn't we already go through that? Although David suggested that those are spinnaker halyard cleats, I am pretty sure that they're for the centreboard uphaul. The line that goes through the fairlead eye runs along the port side of the centreboard case and comes up through the exit block at the front end of the case.

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Thread starter #43
OK, I think the purchase system is the first thing I'm going to put together, that and order up some line. I want to have a different color pattern for each purpose in the boat. The thing is going to look like a christmas tree.

Looking at Harken blocks at different places and I notice that many of the blocks (like the 408 that I want to use for the vang) come in an "F" version. "F" for "fishing". Are these significantly different from the non-F versions, do you know?
 

LaLi

Well-Known Member
#44
I want to have a different color pattern for each purpose in the boat. The thing is going to look like a christmas tree.
Very un-1970-ish... but very practical. At the time, almost all suitable rope was white. When I was setting up my first 470, I wanted the jibsheet to be easily visible, so I chose a red line for that. The mainsheet already happened to be blue, and the colour system developed from there :D

Looking at Harken blocks at different places and I notice that many of the blocks (like the 408 that I want to use for the vang) come in an "F" version. "F" for "fishing". Are these significantly different from the non-F versions, do you know?
I have no idea! Could you give a link?

By the way, I'm not sure if the 408 would work on your vang. Have to test it (it's about the angles). The classic 086 definitely would.

Where do you plan to do your shopping anyway? I can recommend APS - Annapolis Performance Sailing | APS as having a wide selection and lots of expertise. Or do you have a favourite walk-in store closer to you?

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LaLi

Well-Known Member
#46
"F" for "fishing".
Harken 408F
Weird. Very weird. There seem to be "F" version cleats and eyestraps, too!

But you can see that it's something that shows up at general marine stores and ones for other water activities than sailing, not sailing specialists. Maybe it's a mistake/misunderstanding that just spread. Or even a practical joke.

In any case, those seem to be identical in every way. Including price, which is the ultimate giveaway that it's the same product.

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LaLi

Well-Known Member
#49
I think I have a set like that somewhere... they're too narrow for a Lightning, but if they're good for a 420 mast and gate, they should work on a 470, too. If you go down the chock route, you can even make them yourself out of nylon or some similar material. And then there's this guy in Connecticut if you want to spend some money.

Measure your mast gate in any case - there shouldn't be much sideways play, and you may want to attach plastic shims to the sides of the gate opening to minimize it. Also measure if the gate is centred; if not, you can centre the mast by attaching a thicker shim on the other side. (This sort of detail may sound too racing-oriented, but it's about safety, too.)

As it's the default rope for control lines on Nickels-built boats, I've pulled a lot of Sta-Set during the last couple of years :D It's fine for the cleating parts in control systems, but you can't call it "low-stretch", and should use something stronger for the primary lines in a vang, for example. If NE ropes is your favorite rope maker, then you'd go for their 3 mm Endura 12. Their 4 mm Finish Line should be good for lighter-loaded systems (like the main cunningham) and is good in cleats, too.

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LaLi

Well-Known Member
#52
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:eek: Thanks, West Marine.

But the ropes are ok :D Any single-braid 12-strand Dyneema is good for non-cleating parts of purchase systems. I probably wouldn't choose single-braid Vectran, though, as it's not as durable - it doesn't stretch, but it has a "best before" date. I'm trying it out on my Laser traveller and it's ok so far.

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Thread starter #55

I've purchased my blocks, line and some other hardware to rig up the Purchase System for my 470. I want to make sure that I have the routing of the line through the blocks correct. It's tough to see the pattern from this picture.

This is a helpful guide but it puts the blocks at a 90 degree angle with one another.

How To Reeve a 6:1 Purchase – Fosters Ship Chandlery

I'd like to minimize the rubbing of the line, if possible.
 

LaLi

Well-Known Member
#57
There are several ways of doing that, and having the sheaves at right angles does minimize rope/rope friction, BUT it's highly likely that you need to orient the hook block so that there's the least friction against the mast itself (like in the Mackay picture). But it's something that you have to test.

Here's my mockup of the system
The hook block probably wants to turn clockwise (viewed from above) from that position. You have to test it on the boat, try different ways and choose what works best.

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Thread starter #58
I'll get my wire for the bottom made up later today and try it on the boat. The vang is next. I'll have to find a neat way to attach the upper block to the boom. After that I guess I should think about setting up a cunningham rig.
 

LaLi

Well-Known Member
#59
I'll get my wire for the bottom made up later today and try it on the boat.
At this point, you should check the mast foot position, because it's going to affect everything you might attach to the mast step.

Measure the distance from the transom to the aft edge of the mast. The spar should stand at 90° to the mast gate (just for this measurement!), and you should include the mainsail track, as if it came all the way down where it's actually cut off now below the boom. The reading should be about 3095 millimetres. Chances are that the mast foot is farther back (smaller number) than that now. This is also part of the basic tuning; your sails may be some very old cut which may have used settings very different from the modern ones, but I still think that is the best figure to use as a starting point.

Depending on where the mast sits in the step, you will have a number of holes available for attaching stuff. The way we do it on Lightnings (they still have this kind of old-school mast steps) is to attach bolts that go across the whole step fitting. You can then shackle anything to them.

The vang is next. I'll have to find a neat way to attach the upper block to the boom.
You already have a neat way, the Laser vang key. Did you buy something that it doesn't fit? If you got the 340 which Harken recommends (for some unknown reason; the swivel is totally useless), then just add another shackle, or the 093 adaptor.

A couple things that I've noticed which will affect the vang setup: 1) the exit blocks right in front of the traveller are clearly angled down, and 2) the vang attachment point on the mast appears to be above the top level of the centreboard case. That means that the vang line is supposed to run via the mast step. There should be two single lead blocks there (the line comes to them from straight above, from the block(s) at the mast fitting). Now, you have two single blocks on the port side in front of the mast step which you can recycle for this!

After that I guess I should think about setting up a cunningham rig.
I believe the cheek block on the port side of the mast is intended for that, as well as the port side Clamcleat on top of the centreboard case. Once on the water, you will notice that you want a lead block behind it (it can be quite close to the traveller), and a cleat that has a fairlead and isn't at an angle to the centreline. And is made of metal :rolleyes: (Of course, the same applies to the Clamcleat on the other side, too.)

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Thread starter #60
You already have a neat way, the Laser vang key. Did you buy something that it doesn't fit? If you got the 340 which Harken recommends (for some unknown reason; the swivel is totally useless), then just add another shackle, or the 093 adaptor.
Yes, of course, I have the laser thingie that I'll use. The Harken 093 should do the trick.

That means that the vang line is supposed to run via the mast step
I think the vang is supposed to run off of the metal strap on the lower, rear of the mast (the one that the inadequate vang is hooked into in the pictures). Connecting the vang at the mast step allows it to interfere with the front centerboard trunk.

I'm going to try setting up the new jib purchase system to the existing I hook on the mast, rather than to the mast step. Connecting to the mast step will likely cause interference with both the vang and the spinnaker halyard. It remains to be seen if this setup will allow enough room for proper tensioning of the jib, however. I'll try it out as soon as I can get up to the boat.

At this point, you should check the mast foot position, because it's going to affect everything you might attach to the mast step.
I'll have to check this out as well. I'm a bit confused about the details here but I'll reread this thread when I'm at the boat and see if I can figure out what you mean, specifically.

What do you recommend for line for my jib sheets (both type and diameter) and the same for my spinnaker sheets?

I'm still waiting for my I beam traveller brace and hardware for the vang. It's feeling like it will be fall before I get this thing in the water.
 

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