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Re: Internal Downhaul Recommendation [Re: tback] #112268
08/09/07 12:54 PM
08/09/07 12:54 PM
Joined: Aug 2005
Posts: 2,921
Michigan
PTP Offline
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Michigan
I am trying to remember what I saw when I looked into the base of the mast recently but I only remember seeing two blocks up top and then the DH line coming in one side of the mast to a block then to the other side. This is diffrent than the int DH on my prev boat.
Sorry, no help. If I had my camera with me then I would have taken pics but it would have been difficult.

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Re: Internal Downhaul Recommendation [Re: tback] #112269
08/09/07 06:24 PM
08/09/07 06:24 PM
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Posts: 9,582
North-West Europe
Wouter Offline
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Quote

can someone mock up a diagram of what's going on inside the mast?



Here you are :

[Linked Image]

Wouter

Attached Files
Last edited by Wouter; 08/09/07 06:24 PM.

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Internal Downhaul Recommendation [Re: Wouter] #112270
08/09/07 08:57 PM
08/09/07 08:57 PM
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Michigan
PTP Offline
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yep, thats it.
I take it there Is a becket that the other end of the red line is attached to on the block inside the mast to the left

Last edited by PTP; 08/09/07 09:03 PM.
Re: Internal Downhaul Recommendation [Re: PTP] #112271
08/10/07 03:05 AM
08/10/07 03:05 AM
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North-West Europe
Wouter Offline
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Yes,

Basically it is a three stage cascaded setup.

First stage (blue line) is a 2:1 with a nice soft 5 mm swiftcord line or something. You'll be holding this line in your hand.

The second stage (red line) is a small diameter and very flexible high tension line like 2 mm D12 or 3 mm dyneema. The purchase here is 3:1 making the total internal setup a 6:1

The third stage (green line) is a 2:1 system with a 4 mm dyneema line with a tough outer mantle. This is needed as it does rub against the goose neck or other components a little bit. And it is out in the elements (UV radiation etc).

The internal 6:1 setup followed by the outward 2:1 setup make for a 12:1 setup overall. By using the different line diameters this setup is cheaper and runs more smoothly then any other downhaul setup. This is especially so since most of it is inside the mast and thus well protected from weathering and salt.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Internal Downhaul Recommendation [Re: Wouter] #112272
08/10/07 08:34 AM
08/10/07 08:34 AM
Joined: Mar 2006
Posts: 1,246
Orlando, FL
tback Offline OP
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tback  Offline OP
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Orlando, FL
Thanks Wouter ... and the other end of the blue line comes out the opposite side of the mast.

Good Luck this week at the GC.


USA 777
Re: Internal Downhaul Recommendation [Re: Wouter] #112273
08/12/07 11:37 AM
08/12/07 11:37 AM
Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
David Parker Offline
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David Parker  Offline
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Dunedin Causeway, FL
[Linked Image]
[/quote]

I'm interested in building this. The internal crosspiece will carry a huge load. Questions:

1) How far up the mast is the internal crosspiece?
2) Is that crosspiece really "Z" shaped? What is it made of? How thick is the stock material?
3) How is this crosspiece connected to the mast, rivets or a bolt all the way through?
4) The drawing is just a schematic. In reality, could one or two of the internal blocks be a double or MUST they be 2 singles to achieve the cascade effect? First, the 2 on the crossbar could certainly be a double, right? Although only one single is shown for the blue, there must be another that is not shown. Could that be a double? That one might be too close to work as a double, space wise. Hmmm... Wout?

Re: Internal Downhaul Recommendation [Re: David Parker] #112274
08/12/07 02:35 PM
08/12/07 02:35 PM
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France
pepin Offline
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Quote

4) The drawing is just a schematic. In reality, could one or two of the internal blocks be a double or MUST they be 2 singles to achieve the cascade effect? First, the 2 on the crossbar could certainly be a double, right? Although only one single is shown for the blue, there must be another that is not shown. Could that be a double? That one might be too close to work as a double, space wise.

The top blocks can be replaced by a double but the two floating ones must be independent. Think about it: as you pull on the downhaul the blue/red block goes down and the green/red one goes up. If you attach them together, nothing will work.

Why do you think there is another block for the blue line? It's just entering by one side of the mast, going up to the block and down to the other side...

Re: Internal Downhaul Recommendation [Re: David Parker] #112275
08/12/07 03:31 PM
08/12/07 03:31 PM
Joined: Feb 2006
Posts: 3,348
F
fin. Offline
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F

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Posts: 3,348
Quote

I'm interested in building this. The internal crosspiece will carry a huge load. Questions:

1) How far up the mast is the internal crosspiece?
2) Is that crosspiece really "Z" shaped? What is it made of? How thick is the stock material?
3) How is this crosspiece connected to the mast, rivets or a bolt all the way through?
4) The drawing is just a schematic. In reality, could one or two of the internal blocks be a double or MUST they be 2 singles to achieve the cascade effect? First, the 2 on the crossbar could certainly be a double, right? Although only one single is shown for the blue, there must be another that is not shown. Could that be a double? That one might be too close to work as a double, space wise. Hmmm... Wout?


On my Blade the "z" is a stainless steel bolt inserted through a piece of aluminum tubing, inside the mast. It is about 62" from the base plate.

Pictures follow.

Attached Files
115422-DH3.JPG (267 downloads)
Re: Internal Downhaul Recommendation [Re: fin.] #112276
08/12/07 03:32 PM
08/12/07 03:32 PM
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F
fin. Offline
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another.

Attached Files
115423-DH1.JPG (315 downloads)
Re: Internal Downhaul Recommendation [Re: fin.] #112277
08/12/07 03:32 PM
08/12/07 03:32 PM
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fin. Offline
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another

Attached Files
115424-DH2.JPG (317 downloads)
Re: Internal Downhaul Recommendation [Re: fin.] #112278
08/12/07 03:33 PM
08/12/07 03:33 PM
Joined: Feb 2006
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F
fin. Offline
Carpal Tunnel
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F

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last one.

Attached Files
115425-DH4.JPG (384 downloads)
Re: Internal Downhaul Recommendation [Re: pepin] #112279
08/12/07 08:53 PM
08/12/07 08:53 PM
Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
David Parker Offline
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Dunedin Causeway, FL
Quote
Why do you think there is another block for the blue line? It's just entering by one side of the mast, going up to the block and down to the other side...


The comment about the other end of the red line is still a question. Going back to a Wouter post from 2005 I found this drawing.

[Linked Image]

I'm guessing that this is NOT what is the photo from THIS thread. PTP's comment above says a lot.
"...there is a becket that the other end of the red line is attached to on the block inside the mast to the left."

This latest setup is simpler and 12 to 1 compared to the old photo I've shown here.

Re: Internal Downhaul Recommendation [Re: David Parker] #112280
08/12/07 09:03 PM
08/12/07 09:03 PM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
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David,

You are showing the diagrams of two cascaded downhaul systems that are on the OUTSIDE of the mast. Often seen on F18's. This is a 2-stage cascaded setup

F16's however predominantly use the internal downhaul system which has a significantly different diagram as it is a 3-stage cascaded setup. See the diagram in my own earlier posting.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Internal Downhaul Recommendation [Re: Wouter] #112281
08/12/07 09:43 PM
08/12/07 09:43 PM
Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
David Parker Offline
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David Parker  Offline
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Posts: 890
Dunedin Causeway, FL
OK, last question (not!). The green external 2 to 1 exits the mast, goes up and around a block on the tack of the main and down to...what? A clam cleat or an eyestrap on the mast? That would complete the last 2 to 1 cascade, right?

That means there are 3 exit blocks on the mast, two that lead through the mast, into cleats, and on to the sailor's hand and a third for the green to the tack cascade.

So the entire inventory of needed hardware is

1) a double block on the crossbar
2) a single with becket for the green to red
3) a single for the blue internal
4) three through-mast exit blocks
5) two cam cleats
6) stainless bolt and tube for the crossbar.
7) clam cleat or eyestrap for the end of the green.
8) appropriate lines.

Sound about right to you folks? Any of those blocks need to swivel?

Pete, thanks for the 62 inch measurement (1575 mm). I would never have guessed it was so far up the mast!

Re: Internal Downhaul Recommendation [Re: David Parker] #112282
08/12/07 09:51 PM
08/12/07 09:51 PM
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F
fin. Offline
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You're welcome. The next time I pull it apart, I'll take some pictures of the inside.

Re: Internal Downhaul Recommendation [Re: David Parker] #112283
08/13/07 03:02 AM
08/13/07 03:02 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
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Wouter  Offline
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I used just an eyestrap ti which I tie the green line with a slip knot. Like that it comes off very easily even when alot of downhaul tension is put onto it. Jam or cam cleats tend to let the green line slip or strip the mantle of the core. Eyestrap is best in my opinion. The VWM Blade has a sail hook on the end of the green line that hook into a hole on the base plate.

62 inches sounds like alot but with thsi 12:1 system you can REALLY downhaul your mainsail. I'm getting 5 to 6 inches of downhaul between tensioned and fully tensioned. When the sail is slack it is something like 10 inches. This mains the blue line block needs to travel 60 inches inside the mast. Either that or you need to pretension the setup but repositioning the slip knot in the green line. My setup is just a little too short to go from fully slapck to fully tensioned and so I use this slip knot trick to preset the tension or the conditions I'm expecting. I can even do that easily on the water and have.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Different way to Rom [Re: David Parker] #112284
08/13/07 05:23 AM
08/13/07 05:23 AM
Joined: Sep 2001
Posts: 267
Switzerland
alutz Offline
enthusiast
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Joined: Sep 2001
Posts: 267
Switzerland
The way I rigged the downhaul on my Mattia 18HT
[Linked Image]

I think the advantage of my setup was, that it was easy to install and to get the right lenght of the lines.

But I must admid, that the setup of the Typhoon F16 looks allot cleaner.

Last edited by alutz; 08/13/07 05:25 AM.

Andi, Switzerland
Team OST
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