In-boom outhaul rigging. Could use some help...

[stickinthemud57]

One of my winter projects is to set up a pulley system inside the boom to adjust outhaul tension. One approach that looks good to me is shown in "Outhaul Plan A".

Another is "Outhaul Plan B"

I do not have the hang of figuring out mechanical advantage ratios. Could someone tell me what the ratios for these two approaches are?

 

[PaulK]

Plan A looks like 4:1. The blocks at #2 and #4 only change the direction of the line; they don't add anything to the mechanical advantage. The first block # 3 provides 2:1 and the second block #3 doubles that. Plan B does not look like it would provide any mechancal advantage. If you pull in the line at "A" two feet, the block B that it is attached to will move one foot. When block B moves one foot, the line attached to the sail tack will have to move two feet. This will nullify any mechanical advantage and the different blocks will simply be adding friction to the equation. Set up the blocks and lines on a flat surface and you will see. If this is for a MacGregor 26, do you actually need as much as 4:1 for the outhaul? 2:1 might be plenty. The shock cord also adds complexity that may not be necessary.

 

[stickinthemud57]

Thanks for your explanation. Usually physical puzzles are no problem for me, but all these pulleys have me flummoxed.

Yes this is for a 26S, so 2:1 may be sufficient. I figure why not 4:1 since I'm in there anyway, right? Twice the amount of rope hanging out the bottom of the boom, correct?

The bungee comes from the Plan A approach and was copied in Plan B. I can see how it would work to maintain at least a small amount of tension on the system (to help prevent fouling, maybe?). Worthwhile? I'm not sure.

Thanks again for getting me straight on the pulley systems!

Oh, hey. Any thoughts on using Dyneema line for this project?

 

[PaulK]

From what people hear about MacGregor 26's, Dyneema could be overkill. Would still work, though.

 

[AlanRothenbush]

From what people hear about MacGregor 26's, Dyneema could be overkill. Would still work, though.

I concur, Dyneema is, IMHO, a poor choice. It's completely overkill for the forces involved, making it needlessly expensive.

And while it's much (MUCH) easier to splice an eye in the end than conventional double braid, the "fat" portion is also much much longer, which sometimes causes problems.

Mostly though, it's not as nice to "handle" as conventional line; the added "slipperyness" is just never a good thing.

Let me give you two things to think about.

1. Consider so called "regatta" braid. It's made out of conventional material, so it handles nicely. Actually, it handles nicer than double-braid because it just refuses to hockle; bundling it up "wrong" (i.e., no figure 8 loops) isn't a problem.

And because it's hollow, spicing eyes are again trivial. But because it's not insanely slippery, you don't need a 48x bury; a short bury and a bit of sewing (belt and suspenders philosophy) and you're done.

2. Consider no tackle inside the boom, save for a pulley at either end. Run the line out the front of the boom, down to another pulley and back to the cockpit. At the cockpit, you can have a cleat or a jammer AND use a winch (if there's one handy.

If you're clever and careful, there should be no real change in outhaul tension as the boom swings from side to side. (This IS something to consider in the planning, though.)

For the record, I did exactly this on my 28' boat. I had a fancy (or so I thought) internal arrangement that caused nothing but grief, so I now run a single line out the front, down and back. I'm not sure I've ever used the winch to tension it though.

And should I need (or want) to play with tension, I can do so without leaving the tiller.

(I have this thing about the safety of the cockpit. You never forget going for an unplanned swim in the middle of the Pacific ...)

Hope this helps.


Alan

 

[stickinthemud57]

Yes, definitely overkill, but I like that it has such low stretch characteristics. As short as these lines will be, cost is not a huge factor, IMO. Others have pointed out how slippery it is, so I will most likely just use it for the load end, and select something easier to grip. The regatta braid sounds like a good solution.

Placement of the cleat will be a combination of cockpit convenience and the ability to access it when running downwind or close hauled. I can always mount two clam cleats for more versatility as long as I have enough extra line.

@AlanRothenbush, I already run my reef lines outside the boom on the starboard side, and want to minimize dangling ropes and tackle. I'm hoping that the bungee will help keep things in order, so will be trying the internal setup first to see how things go. What sort of problems were you experiencing?

Thanks, all, for the advice!

 

[Tally Ho]

The outhaul on my O’Day 322 is just a straight shot through the boom. It is routed to cabin top winch, but I can almost pull it by hand.

Is it common to need 2:1 or 4:1 leverage on the outhaul? Or is it because these are not routed back to a winch?

Just curious.

Greg

 

[Groundhog246]

One of my winter projects is to set up a pulley system inside the boom to adjust outhaul tension. One approach that looks good to me is shown in "Outhaul Plan A".

Another is "Outhaul Plan B"

I do not have the hang of figuring out mechanical advantage ratios. Could someone tell me what the ratios for these two approaches are?

2:1 was plenty on my Tanzer 26. I can't see a 26S needing more, unless perhaps you have a loose footed main. Modify plan B and instead of the doubled block use a single block and attach your out haul there. I also approve bringing your line forward to where you can reach it from the cockpit no matter how far outboard the boom lies. Dynema seems excessive for such a short length.

 

[stickinthemud57]

The outhaul on my O’Day 322 is just a straight shot through the boom. It is routed to cabin top winch, but I can almost pull it by hand.

Is it common to need 2:1 or 4:1 leverage on the outhaul? Or is it because these are not routed back to a winch?

Just curious.

Greg

No winch involved, so some advantage will be needed. 4:1 should do it, I think. I see the advantages in the rig you describe, and thank you for that.

My goal is to be able to adjust the outhaul while minimizing the number of ropes and pulleys sticking out here and there. Putting the works in the boom reduces on-deck clutter and makes use of otherwise unused space. It's worth at least trying, I think.

Thanks again for the advice and comments!

 

[shemandr]

I don't know if you should use dyneema or not. But I would choose the lowest stretch line I could find for a sail control which controls the depth of the lower half of the main. I don't think it matters what the boat is. When you want the main to be flat you want it to stay flat.

 

[stickinthemud57]

I can't see a 26S needing more, unless perhaps you have a loose footed main.

I do have a loose-footed main. Should have stated that.

 

[AlanRothenbush]

@AlanRothenbush, I already run my reef lines outside the boom on the starboard side, and want to minimize dangling ropes and tackle. I'm hoping that the bungee will help keep things in order, so will be trying the internal setup first to see how things go. What sort of problems were you experiencing?

I guess my biggest problems were dangling lines and inconvenient access.

Not having any good idea how much force would be required, I rigged up a 4:1 purchase inside the boom. Then, having no good idea how much outhaul travel I was ever going to use, I allowed for 3 feet. (This turned out to be way more than needed, but it's only line, and heck, experimenting with sails is half the fun of sailing). I added a bit more to pull on, and so that was 15 or 16 feet of line to be coiled up and dealt with.

Hanging off the boom, it was annoying. In a bag in the cockpit with the reefing lines, no problem.

The access was a bigger deal. From the cockpit, it's easy to tweak a bit here, tweak a bit there. I can't honestly say it ever made all that much difference, but it did make some difference and on a small boat, half a knot is a pleasant bonus.

If I had to leave the cockpit to adjust the outhaul, I really wouldn't be tweaking at all. I'd set it once and probably not change it for the rest of the day, which kinda defeats the entire adjustment idea.

I guess this comes down to what kind of sailor you are.

I find myself sailing single handed a lot, really 99% of the time. Since I've heard all my own stories more than once, I don't spend a lot of time talking to myself, so I have a lot of time to fiddle about.

If I sailed with company though, I'd certainly spend more time chatting and less time making minute changes. After all, if it doesn't matter where you're going, it really doesn't matter how quickly you get there.

Note that I've left out racing in the above discussion, which might change the decision; solo or crewed, 'round the cans or long distance all have differing requirements.

 

[Joe]

Both systems are "cascaded" . the control line is anchored that is doubles the purchase of the system it pulls on. The on the left(A)is a double cascade. pulling a 2:1 straight line system, where you simply add the number of blocks. 2x2x2=8, too much for a loose foot, light rig like the 26s. The right (B) has just the one cascade pulling a 2:1 purchase, 2x2=4:1 and I'd choose that one. You can use dyneema. but you'd want to cover the end you handle with a larger diameter outer layer, maybe even two. If it was me I'd stick to wire and put a eye you can tie on a piece of 5/16 that cleats and handles better. The geometry is important... but you have a lot of length to work with, since the outhaul on a traditional sail only moves a couple of inches. I wouldn't worry about the blocks dragging. If pressure of the sail will always keep tension on the line. Even if it does clank, put some tension on the line. My Cat 27 uses the B plan. 1/8 wire on the aft end, 5/16 double braid on the cascade (forward) end. The line runs from the exit block forward, through a padeye to a vee or clam cleat fairlead on boom near forward part cockpit. This is to make the control line reachable when the boom is swung out and keep the line captive, by the cleat on the boom and not drooping into the cockpit when it's uncleated. Have fun... it's a very important mainsail adjustment.

 

[stickinthemud57]

I have mocked up my 4:1 in-boom outhaul adjuster (see attached photo). My plan is to install it when I pull the boat out for the winter. Your comments/insights would be welcome.

 

[Scott T-Bird]

I have a couple of comments. I've found the most vexing problems associated with my inside-the-boom outhaul setups is stuff getting snagged inside the boom. I can't tell what causes it, but it's a problem that only grows from complexity and it's frustrating.
Your system seems simple enough and will provide enough purchase. Don't bother with the bungee. I can see that it is intended to assist the sail in filling out draft when the outhaul is eased. Once the bungee has been extended for long periods (for instance when you flatten out your sail to flake on the boom) it will be stretched out and non-functioning. When I want to fill out the draft, I either let the wind do it or I assist by pushing on the center of the foot. The bungee will only be a complexity that doesn't assist you and can lead to problems.
Also, don't use any bowlines inside the boom. Have your lines fitted with eye-splices. I've made that mistake. Bowlines inside the boom lead to snags.

 

[Kingjim91]

For additional reference, here is the layout for a Catalina 30 internal outhaul.
I think it’s 3:1, but I’m no expert. At any rate, I don’t need a winch, especially after switching to a loose-footed sail.

 

[stickinthemud57]

I have a couple of comments. I've found the most vexing problems associated with my inside-the-boom outhaul setups is stuff getting snagged inside the boom. I can't tell what causes it, but it's a problem that only grows from complexity and it's frustrating.
Your system seems simple enough and will provide enough purchase. Don't bother with the bungee. I can see that it is intended to assist the sail in filling out draft when the outhaul is eased. Once the bungee has been extended for long periods (for instance when you flatten out your sail to flake on the boom) it will be stretched out and non-functioning. When I want to fill out the draft, I either let the wind do it or I assist by pushing on the center of the foot. The bungee will only be a complexity that doesn't assist you and can lead to problems.
Also, don't use any bowlines inside the boom. Have your lines fitted with eye-splices. I've made that mistake. Bowlines inside the boom lead to snags.

Thanks for that. Actually, the purpose of the bungee is to keep enough tension on the system when not under load to minimize stuff getting snagged inside the boom.

Thanks also for your advice re the bowline knots. I will take that into consideration.

 

[Scott T-Bird]

Thanks for that. Actually, the purpose of the bungee is to keep enough tension on the system when not under load to minimize stuff getting snagged inside the boom.

NIcely thought out! I hadn't considered that purpose. Still the problem that when extended for long periods they tend to lose function, but perhaps that won't be a problem and/or the bungee can be replaced.

 

[stickinthemud57]

NIcely thought out! I hadn't considered that purpose. Still the problem that when extended for long periods they tend to lose function, but perhaps that won't be a problem and/or the bungee can be replaced.

Well, I wish I could claim it as my idea...

Yes, I expect at some point replacement of the shock cord will be necessary. I am slightly encouraged by the "marine" designation for the shock cord (even though I bought it at Loew's) and the fact that it will protected from the elements inside the boom. I have doubled it in case one breaks, and plan to re-secure the end caps with screws to facilitate servicing. Time alone will tell, I suppose.