John? RE Daggerboard rigging diagram

[dave]

Thanks, I'll see what I can do with that.

When I go the that file and right click, I see no "add" anywhere. What's up with that?

[Runaway#23]

Dave;

To upload an attachment, look at the second tab below the submit/ preview button at the bottom of the screen. It will allow you to link the file to attach. One problem though is that sometimes large files will not upload as there is a limitation on file size per website design.

I found a Harken 308 as you recommended, and it uses a 5/16 bolt to attach it to the tang. It will take 1/4 inch or 5/16 line just fine. The 311 shieves you describe appear to essentially be the same roller bearing shieve included in the 308 - just without the side plates, so installing them in the crane with a couple of coffee can lid-shims makes sense, given the 1/2 in + of room left by the cheapies.

So far so good.

But I wanted to ask your opinion regarding using a 60 mm Lewmar 2990 6601 torlon bearing foot block to replace the Schaefer cheekblock on the deck. Working load is 880 lb and it will acomodate up to 1/2 in line. I found one cheap ($30) and thought it might work -

[dave]

The reason that I use the blocks that I do is because of space, ROLLER bearings and working load. The 311 sheaves are what's in the 308.

I personally wouldn't recommend using anything larger than 1/4" line and 3'/16" is better. People need to retrain their brain on thinking that thicker line is easier on the hands. The smaller line makes LESS friction running through a block and tackle system and that means that it requires LESS effort to move the same load the same distance. This is made even more moot [large diameter line] on the board raising because a winch is used. If you are having to pull much at all on the tail, there aren't enough wraps on the winch. When a winch is used for ANYTHING, the winch is supposed to do the work, that's what it's there for.

[orion27]

S2 7.9 DB.jpg (55.69 KiB) Viewed 5576 times

[dave]

John, thanks for loading that. I had a thought [kind scary] ! Since the blocks are being mounted onto the SS bar coming out of the board there's [of course] no need to even use the backside plate on the 308, and only one plate needs fabricated to mount the smaller block on top of the 308. Folks just have to remember to use nylocks on the back of the tang and don't torque the hell out of them!!!

[Runaway#23]

Isn't technology great? Thanks Dave and Tom for the collaboration. i did see a similar arrangement showing the line terminating through a hole in the horizontal crane plate - off to the left of the pulley plates (outboard of the upper pulley. Using that arrangement, the terminating line would go from the plate to the lower tang pulley, outside of the bottom crane pulley then under the upper tang pulley and exiting from the upper crane pulley.

six of one, half dozen of . . . . .

But it seems that if the tang extension is long enough to pin the board up, your pin hole needs to be moved almost directly below the pin hole for the upper crane pulley or to a spot just under angled tang guide if it is not to interfere with the tang as it rises through the crane assembly.

So there may be possibly two workable solutions, depending on the placement of the line terminating (bitter) end.

[dave]

Just so we are clear, the only way that this will work as far as the running rigging goes is this: The line coming from the deck turning block enters the starboard sheave on the CB crane, runs down to the BOTTOM block, up to the port sheave on the CB crane [outside to inside] and then back to the smaller top block above the 308 and then up to a hole/pin that's drilled in the CB crane plates. Make sure that the dead end hole is drilled as close to the center as possible to stay out of the way of the line coming down from the starboard Sheave AND to get the maximum mechanical advantage. It's s tight fit in there so measure 3 times and drill once. Memory tells me that I couldn't get the hole as close to the center as I wanted because of clearance issues for the pin and bowline at the dead end. I tied a really small bowline before putting the line up between the plates and then pinned it. That's the only way to keep the top block on the tang from bottoming out on the knot.

This may have been what you meant, but it didn't sound that way. One more note: as I have said, when this arrangement is used the board comes up so easily that an overzealous crew WILL pull the top block on the tang up into the bottom of the CB crane. After installing this setup it would be wise to raise the board without the CB trunk covers on and when the tang gets a few inches from the Crane, MARK the line where it exits the CB crane sheave. The first mark is a warning that the board is close to all of the way up. A second mark should be placed on the line just BEFORE the locking holes line up.

[Runaway#23]

Dave;

Did you mount the 308 to the forward or aft side of the keel tang? My crane is positioned exactly as in your diagram - if viewed from the cockpit, wirh the tang (pin up) guide facing aft as well. In that case, a line exiting from the stb crane shieve would exit below the deck level -

[dave]

On our boat the sheave that's above the deck is the starboard side...............................

It shouldn't matter one way or another as long as there are no crosses in the tackle.