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arjand · 23-02-2012, 12:42

Hello!

Below some pics from my bow.

I have an asym that came with the boat but where do I lead the tack to without having big shaving issues (drum of the roller furler) and without a major redesign job of the complete bow assembly?

Any tips?

Thanks!

cwyckham · 23-02-2012, 20:49

I had the exact same problem. My short term fix was to run a piece of amsteel from the stem fitting up to a shackle for the asym. I keep it away from the furler with a loose loop to the pulpit.

It is very non-ideal because I am putting some side load on the pulpit. It's a lot better than just taking it right off the pulpit, though. With my particular geometry, it's just about all coming off the stem fitting with some aft load on the pulpit, which is the direction of most strength for the pulpit.

My long term solution is similar. I plan to pay a welder to install two diagonal members down from my pulpit to my bowsprit. By also welding in the front piece of the pulpit, I'll have a strong tripod for the tack attachment.

**Bash** · 23-02-2012, 20:51

Quote:

Originally Posted by arjand

I have an asym that came with the boat but where do I lead the tack to without having big shaving issues (drum of the roller furler) and without a major redesign job of the complete bow assembly?

chaffing issues?? Best practice would be to have a bail welded to the roller. Any good yard will be able to figure this out once you tell them what you need the bail for.

cwyckham · 23-02-2012, 21:31

Of course, the best option of all is to install an extendable bowsprit. There are some nice ones that bolt right onto the foredeck. I considered it, but just don't have the space for it.

cwyckham · 23-02-2012, 21:35

Quote:

Originally Posted by Bash

chaffing issues?? Best practice would be to have a bail welded to the roller. Any good yard will be able to figure this out once you tell them what you need the bail for.

Interesting option. Have you seen it used in practice? Can you weld to a typical furling drum or are they too thin? You'd still be rubbing, but then you could put a short tag line of wire rope or replaceable amsteel or something and replace as required without buggering the furler drum. I'd love to see a photo as this could solve my issues as well.

**Ex-Calif** · 23-02-2012, 21:48

Quote:

Originally Posted by arjand

Hello!

Below some pics from my bow.

I have an asym that came with the boat but where do I lead the tack to without having big shaving issues (drum of the roller furler) and without a major redesign job of the complete bow assembly?

Any tips?

Thanks!

Here are some off the shelf ideas.

I would consider taking square stock and tying into the two unused holes on the port side of your stem fitting. I would add a square block milled to fit into the bow fitting aft of the furler and tie the fabricated bowsprit through both sides of the stem fitting and the spacer/clamp block with excellent shear capable bolts.

I would size the length as need to clear the bow and drill the forward end to accept a shackle etc...

Basically an adaptation of the home grown one shown in attached photo.

Valkyrie654 · 23-02-2012, 22:13

I would be very careful about using the bow roller as the attachment point for the tack line. I have seen the rollers pulled right off of the deck. I have also seen them bent upward. Bow rollers for the anchor are designed for downward loads, and some side loading. Same thing for the attachment hardware.They are not not designed for an upward load. The majority of the stresses will be upward. A short sprit would be the best solution, but not always the easiest

**FSMike** · 23-02-2012, 22:24

I don't suppose the previous owner might have an ideal solution?

**Ex-Calif** · 23-02-2012, 22:42

Quote:

Originally Posted by Valkyrie654

I would be very careful about using the bow roller as the attachment point for the tack line. I have seen the rollers pulled right off of the deck. I have also seen them bent upward. Bow rollers for the anchor are designed for downward loads, and some side loading. Same thing for the attachment hardware.They are not not designed for an upward load. The majority of the stresses will be upward. A short sprit would be the best solution, but not always the easiest

+1

A friend had his bow roller bent sideways in a blow. I would also not favor attaching any sail to the pulpit unless specially designed for it.

arjand · 24-02-2012, 04:31

Thanks for all the input! I came across a cheap skate solution yesterday: add a big pad eye just aft of the fore stay combined with the ATN tack w add'l line to minimise side pressure on the fore stay. This works for us as we will only use if for big distances, so no need to gybe. Emergency gybes are still possible but will be ugly as the spinaker halyard attached above the gyb.

Capt.Don · 24-02-2012, 06:35

I spent a lot of time working through this same issue. I described my experimenting process on my blog at Tartan 3500 - Intuition: Analysis of spinnaker tack block placement.

Essentially I used an REI climbing loop to secure the block at the base of the headstay. I found in some conditions that the block would press against the roller furler. To remedy this, I routed the tackline forward around the anchor roller, through the block to the sail tack. This provides a small forward force to keep the block away from the drum.

I'm finding this works very well. The tackline sits nicely forward of the headstay and inside the bow pulpit. I'm happiest with this configuration. Note, standard disclaimer - other boats' bow pulpit and anchor roller may not provide the same geometry

Don

arjand · 24-02-2012, 06:40

brilliant blog post! Thanks!!

DJBrookster · 24-02-2012, 08:16

Quote:

Originally Posted by Ex-Calif

+1

A friend had his bow roller bent sideways in a blow. I would also not favor attaching any sail to the pulpit unless specially designed for it.

I'm interested to know what you call a blow in beaufort terms? I'd like to rig my asymetric/gennaker from the same place. But surely you"d only be flying it in light air anyway and as such massive loading would not be such an issue. Or am I totally missing the point here?

**Cheechako** · 24-02-2012, 08:43

If your bow roller is going to be damaged by a drifter you need a better roller! :>) Heck on some boats the roller(s) and stemhead fitting are integrated together... The roller should be designed to withstand sever downward force from a chain snubbing up bar tight in a roughwater situation. The lever moment actually pulls up on the aft end of the roller. A drifter will pull up on all the attachments, but is not near so severe a load.... JMHO!

cwyckham · 24-02-2012, 10:25

Quote:

Originally Posted by DJBrookster

I'm interested to know what you call a blow in beaufort terms? I'd like to rig my asymetric/gennaker from the same place. But surely you"d only be flying it in light air anyway and as such massive loading would not be such an issue. Or am I totally missing the point here?

I agree that you'd only want to have it up in lightish air, but stuff happens and that is one huge sail! The forces can be large, which is why I'm not exstatic about my configuration right now and want to find a better solution.