Maybe it's just me but for years I've thought there has to be a better solution to the head knocker cleat on the mast. Yes it's much better than the older styles with a cam cleat on the beam.
But I have a few issues with it:
1) It does come uncleated sometimes, rare but it happens
2) The halyard rarely stays cleated upwind unless you wrap it (but then you always forget to unwrap it and it slows down the hoist) I've added double springs in my cam cleat and it still doesn't hold it upwind.

I work for a company that could make a new one.
We have some smart people on here... anyone have thoughts?

Todd I'll lend a hand, since the problems are annoying me as well.

One needs to look at the line tail geometry. At least on my setup, rigged per Tripp and Mike's guide, the halyard when uncleated upwind still has enough tension on it from the shock cord to keep it out of the spreaders. The downside is this also pulls the halyard out of the cleat to begin with.

So, how do you fix this? The tail has to get to the tramp somehow...that I am going to think on for a few days.

A random thought is leading the halyard to a clutch ala big boat.

One of the infusions at our club has added a normal cleat on the mast, below the halyard cleat, which feeds from top to bottom. After dousing they cleat in the bottom cleat, so any pull on the halyard just yanks it in place

The negative to the base cleat and my clutch idea is it's more difficult to blow the halyard from the port side. Right now I just grab the retrieval line, give it a yank, then grab the halyard tail that's on the deck, give it a hard yank which uncleats it and lets me keep dousing, always staying over the center of the tramp. Hence it's easy to douse on port or starboard.

Is anyone doing something radically different?

Mike just added a plate and 2 cleats to the swivel on the C20 and it worked great. I think 1 large cleat and 1 small.

Any photos Dave? Your description is a little tough to follow, are all the cleats attached to the head knocker swivel, i.e it has 2 cleats instead of one?

Honestly haven't had too many issues since we switched to a nice tapered halyard that is the correct length. It is not cleated upwind, but there isn't any extra slack in the system. After sailing your boat Todd you halyard seemed a bit long.... then again the epicness of that sail has clouded my memory.

If you guys come up with something I would be happy to draw it up in Solidworks.

Mike might have some photos. Yes the 2 cleats are in line and attached to a plate that attaches to the swivel. Take off the existing cleat and make a plate long enough to mount 2 cleats in line and mount using existing cleat bolts and holes. The line just goes through both cleats and they work together.

Never slipped again...

Just like what we put on the Melges spin halyard. Double cleat = no slipping.

hi guys,
i had the same issues on my 20carbon as Mike. Problem was that the cleat is designed for robe-diameters from 6mm onwards. Nacra is using 5mm spin halyards on their race package. just splice a 3mm dyneema inside the area you want to cleat AND Mount a screw with sleave (10mm) through the holes under the cleat. this will protect the stainless base from widening while load is on the cleat. since then no Problems occured.
greetings from Germany
Ludger

Ludger,

Thank you for doing some digging. I replaced my halyard, which is now much more free running and doesn't burn the sail, but now it stays cleated even less than before! Really annoying hoisting the chute more than once downwind! As best I can tell, this is the setup on my Nacra F18 Infusion: http://www.catsailor.com/store/pc/HARKEN-BLOCK-38-MM-PIVOTING-EXIT-150-CAM-MATIC-335p9076.htm

According to APS, http://www.apsltd.com/c-308-harkencamcleatsaccessories.aspx, the Harken H150 Cam-Matic is good for 3-12mm line. Maybe we have the Harken 280 Cam-Matic, which is designed for 6mm line on up? I know I'll be checking my setup this weekend and replacing that cleat regardless.

Sam, maybe i mixed up some figures ....
the spin-halyard line is a hollow-braided type (no core)which is very soft and "compressable". These compression-factor is the problem. A 5mm goes down to <3 mm under load while cleating. Normally the type of line used in cam cams is much stiffer (like on your Cunningham or retriever line), compression rate is less.
In case you splice some rope inside your 5mm halyard to beef it up, wear and tear will rise significantly as the strands of this rope are "widened" from each other.

We solve the slippage problem the other way for the same result - add a 6mm cover over the 5mm halyard where it cleats. Stops the slipping and protects the halyard, when the 6mm cover wears out we replace it, the halyard itself is still in good shape.

Opher,

That was my though as well after I had it slip Sunday. Replaced the cleat with a Harken 150DS=double springs which holds better but the issue is as stampede says, the 5mm FSE Robline Racing Sheet is compressing in the cleat and sliding. Doesn't help that this line is a bit slippery to begin with. Runs really nice though; for a change the spinnaker setup is running smoothly.

Upwind it's not an issue for me; using Tripp and Mike's bungee takeup system, if the halyard isn't cleated upwind it's no big deal, enough tension exists to keep it free of the spreaders.

Mike

What two cleats are you using here?

Harken 365 and 471.

If you look closely, I had to add a riser under the 471 to get the bases in alignment.

Mike,

Can you post a template of the two parts that you fabricated with the materials used.

Thanks