Chotu's Advanced Running Rigging Thread (lots of pics)

[rslifkin]

Needing to put sheet leads on the deckhouse to get a tight enough sheeting angle definitely points to staying to a 100 percent jib for now. You could go bigger with leads up top, bit it'll be a pretty high cut sail and you can only go so big before the boom and jib sheets interfere when off the wind far enough.

[Chotu]

Originally Posted by rslifkin

Needing to put sheet leads on the deckhouse to get a tight enough sheeting angle definitely points to staying to a 100 percent jib for now. You could go bigger with leads up top, bit it'll be a pretty high cut sail and you can only go so big before the boom and jib sheets interfere when off the wind far enough.

after Catsketcher’s post, I am certain this is the whole reason that my design has the blade jib. that is simply what fits. That’s why all these Catamarans have them i think.

I’m glad he posted about that.

ps: we are at a similar latitude. Did you get this storm pretty good? I am bouncing around off of a lee shore right now to it. haven’t been in winds this strong since I put the mast up. It definitely changes the behavior of the boat in choppy water bouncing around. it damped fore/aft pitch motion a lot. bows used to bounce up and down in large chop at anchor like a monohull sailboat. isn’t really doing that anymore. it’s creating some good inertia

[DougM]

I bought my boat in 2020 and it came with a self tacking jib with vertical battens, on a curved track, about 90% lp. Bowsprit with screecher and asymetric for off the wind which i love.

Before i got the boat, I was concerned about the ability to dial in jib sheeting angle in vertical plane, which is controlled by choice of one of three holes on the clew, but it turned out that it trims just fine close to the wind, and adequate out to screecher range. Thusi've never felt the need to change it once i got to know it. Im totally happy with my upwind performance, provided i have, say, 7 or 8 knots minimum

I sail it with horizontal sheeting angles from about 8.5 degrees to 12 degrees depending on the wind. It adjusts with pins, discrete settings, but again, its been fine in practice.

The idea of pad eyes vs track using barber / inhaul for sheeting angle adjustment seems reasonable. easier to tweak if you have a high clew i would think.

My only issue with my self tacker is the relatively small jib area disappoints in light wind, expecially with the little bit of non-serious racing that i do. As such, I seriously considered a genoa which would sheet on the genoa tracks that came with the boat (they are used with the screecher). But when i measured, the sheeting angle produced by the geometry between the headstay and the tracks was in excess of14 degrees so no good. Sheeting angle is fine from end of bowsprit but not headstay. So that really ruled out a larger genoa.

As pointed out before, this is a cabin width issue and I would bet that this limitation would apply to the majority of modern cat designs.

Finally, i'll add that i am looking at trying to fit in a 110 on the tracks, and achieving sheeting angle by inhauling off the mast. But that's about light air and racing, not relevant here. Probably foolish in the scheme of things ...

[rslifkin]

Originally Posted by Chotu

after Catsketcher’s post, I am certain this is the whole reason that my design has the blade jib. that is simply what fits. That’s why all these Catamarans have them i think.

I’m glad he posted about that.

ps: we are at a similar latitude. Did you get this storm pretty good? I am bouncing around off of a lee shore right now to it. haven’t been in winds this strong since I put the mast up. It definitely changes the behavior of the boat in choppy water bouncing around. it damped fore/aft pitch motion a lot. bows used to bounce up and down in large chop at anchor like a monohull sailboat. isn’t really doing that anymore. it’s creating some good inertia

The winds didn't make it this far west. It's actually been pretty warm and calm here the last few days

[Sailorichiban]

Have you checked out the chris white ideas concerning jib handling designs?
His personal 72’ Atlantic has what I would term a boomkin or club with a topping lift.
His has a track, but if I was constructing the setup perhaps one attachment point instead of the track would suffice. Sacrificing some sail shape perfection in order achieve greater durability and simplicity would be a worthwhile exchange in my opinion.
If not closehauled and possibly tacking often then a secondary sheeting arrangement could be utilized.
A club or boomkin also offers the possibility of having a readily used , not needing rigging or much rigging, equivalent to a whisker pole. Of course if used for broad reaching then a preventer would likely be a good precaution.
As always wishing all the best.

[Chotu]

Originally Posted by Sailorichiban

Have you checked out the chris white ideas concerning jib handling designs?
His personal 72’ Atlantic has what I would term a boomkin or club with a topping lift.
His has a track, but if I was constructing the setup perhaps one attachment point instead of the track would suffice. Sacrificing some sail shape perfection in order achieve greater durability and simplicity would be a worthwhile exchange in my opinion.
If not closehauled and possibly tacking often then a secondary sheeting arrangement could be utilized.
A club or boomkin also offers the possibility of having a readily used , not needing rigging or much rigging, equivalent to a whisker pole. Of course if used for broad reaching then a preventer would likely be a good precaution.
As always wishing all the best.

thanks. I looked at this carefully on Chris white’s boat and I think it’s what we were discussing earlier. is there a difference that I’m missing?

[catsketcher]

Gday Chotu

Like Jedi says we always have to be careful of doing things in isolation. Your boat may be no good with a small staysail because you probably do need runners aft where the staysail meets the mast. I have designed only 2 cats and the interconnection between parameters was very intricate indeed.

Of course, you could go massive in your prodder setup later, putting in a system to allow some serious tension on the luff so that your screecher can go to windward a little. Alternatively you can be a little tricky. In the early 80s, before screechers, cats used to use lee bow drifters (basically screechers set on the lee bow and made from plain light dacron with a wire luff). They could go really close to the wind because they could sheet around the cabin but because the tack was way down the beam (close to the lee bow) they could have a really tight sheeting angle. You couldn't tack the beast though, but for a cruiser, having a shorter luff "genoa" that sheets close to the leeward end of the forebeam would give a very tight sheeting angle led to the aft corner fo the boat. Hitchiker catamarans had this setup with twin genoas. John Hitch really liked it and he was a gun racer at the start of multi racing. BUt for tacking you roll up the lee genoa and then unfurl the new lee genoa after tacking - not fast in a thin waterway but fine offshore.

As for booms or wishbones - be careful, each comes with its own issues. The wishbone is great for a main (I love mine) but it and its Camberspar derivative allow no furling and make getting the luff curve correct a real pain. Probably only Dave Calvert would really like to make that sail and having a large wishbone or camberspar whacking around as you pull the sail up would be worrying. I LOVE wishbones on mains, but I haven't put one on my jibs, and for someone who changes their boat as much as me, that is because I can't see almost any benefits. (I am out to work on my wishbone some more as soon as this post is done).

A boom won't do much to help control what you really want to control with a headsail which is twist. A high aspect headsail will have a lot of leech tension and a centre sheeted boom will just allow the sail to twist off as much as it likes. Of course I can think of a way to make a nice deep composite "boom" that is also vanged, but that would require a heap of designing and farting around with epoxy (and you can't do that).

So I reckon you are back to the self tacker with a track. One of the fastest boats I have sailed on (Fantasia - a great 50ft family racer) has a self tacker on a track, but the loads are pretty huge and I was on board once when a few roller balls came out. Get really strong gear or it won't work.

Last idea - You could use a rope system with adjustable tension on the rope AND "sheets" to pull the rope to LEEWARD after each tack (leading down eacg side of the cabin and then aft). You could adjust the tension of the hawse rope and the headsail will tack itself fine but with have lots of twist and depth. BUt when you want to get going (after tacking) you could pull a line to leeward that stretches the whole system tight, making the foot and leech straighter. I have been playing around with a rope traveller on my folding cat project (it is almost back in the water). But the problem is you still need to tighten a rope every tack to get the headsail flat - but it will be lower loading than a typical sheet. Or just pay the money and get a fab track.

[Cavalier MK2]

The jib boom set up I'm used to has a built in "horse". A pad eye is set to one deck side x feet to dead end the sheet which then goes through a block on the underside of the boom towards the clew, the sheet then runs through a block/fairlead - same x distance to the other deck side and then back to your winch. What it gives you is a cheap traveler with twist control when used with the boom. Basically you set the tension on one tack and when you put the helm over it takes up the same sheet angle and leech tension on the new tack. The boom block rides along the rope pulling the leech down as it gets in position.

[Cavalier MK2]

This setup gives a fuller jib shape as you ease sheets, in fact reach to reach down wind tacking can be had. Of course for real speed you'd want a A sail up. Off wind a barber hauler can be set up to give the boom a preventer to help with that whisker pole function.

[Cavalier MK2]

Im adding a 2 second sketch for more clarity. It is easy to see how the down force is added as the jib "travels" on the sheet when tacking.

[Chotu]

hmmmm.

The thread is making me think.

with a pole of some sort, not really a boom but more like a whisker pole that attaches to the forestay or wherever just to hold the sail out, couldn’t you do a double sheet arrangement?

that’s probably what I’m doing on the main anyway.




skip the Traveler, and still be able to locate the clew at any point on the face of the cylinder it arcs in.

Would that work?

On second thought, I guess that wouldn’t be self tacking. But maybe it could be made to be so somehow. not entirely convinced I need a self Tacker anyway. Which was kind of my thought at the beginning of this thread. I wonder if I should just do it like this and then change to self tacking if I feel like it’s necessary

[Chotu]

also, considering the Traveler alternatives, what about something like this? Why isn’t this done? This would be good for the main as well as the jib. it would provide crazy good downhaul ability even if sheeted way way out.

[rslifkin]

Originally Posted by Chotu

also, considering the Traveler alternatives, what about something like this? Why isn’t this done? This would be good for the main as well as the jib. it would provide crazy good downhaul ability even if sheeted way way out.

I think that's a slightly different implementation of the barber hauler concept. No reason you couldn't do that other than the extra weight of lines hanging off the sail. Upwind you'd use just the sheet and let it self tack with some slack in the downhauls, off the wind you use the leeward downhaul for sail shaping (and if the sail is out far enough, you probably use just the downhaul and not the sheet).



Aiming for good control of the sail further off the wind is a good idea, as even after you get the bowsprit and big sails added up forward, this sail is still needed for 2 situations: upwind, and more importantly, when the wind gets too high to fly a spinnaker, code 0, or anything else big.

[malbert73]

Again not a cat person but prior racer- and since the boat/rig/setup is new, wouldn't two fixed jib sheet leads allow you to barber-haul (windward sheet) like we used to do on 420s to go upwind when I raced? Ie on a close reach you just sheet the leeward jib sheet. As you come up to close hauled, you can experiment with windward (prior slack) sheet tension to bring the clew in tighter to allow a closer sheeting angle. This approach would follow the KISS principle until you sail the boat and learn what works/etc.
maybe these come through?
https://www.gbr420.uk/assets/uploads...r%20Hauler.pdf

[Chotu]

OK, it seems like some of the ideas for the jib are pretty good. I think it has evolved enough that I will be able to come up with a drawing and put it up here.

now, the mainsheet is even worse actually.

I painted myself into a corner. I just had to have those davit that I like. The ones that raise the dinghy way way up. It’s great because the dinghy is at a counter level like in a kitchen. You just reach into it and pull the provisions out or put a bicycle in it’s great. but, there is a problem. The davits interfere with the 2 mainsheet system, which is traditionally attached below, to the main structural beam or “centerline transom.”

here are some pictures. This is what is currently out there. I also have 12 feet of Harkin track that was for the job. Is this stuff big enough for the Main?

I also have to go through this brainstorming process about the mainsheet and boom control.

again welcoming lots of opinions on this.

Required: all controls need to lead to the mast base and into the sail control table.

As always, please excuse the mess. It’s a vessel under construction. I have a lot of materials out there