DS 1 gooseneck, boom-vang and downhaul (?) configuration

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DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby jboright » Sat Aug 22, 2020 12:50 am

I'm now the proud owner of a 1970 DS 1 and I've taken her for a couple shake-down runs on pretty low-wind days... Had a lovely time of it and am now working my way through the few issues that have revealed themselves before bringing her into any real wind.
The current one that has me scratching my head is the gooseneck (I'll see if I can add some photos here). I was surprised to find that it isn't firmly attached to the boom... which means that the boom isn't firmly attached to the mast. Is this normal?
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IMG_5535_small.jpg
IMG_5535_small.jpg (24.57 KiB) Viewed 1303 times

There's a pin/rod protruding from the mast-slide part which starts as a square and then tapers to round closer to the tip. This fits in a square shaped hole in the end of the boom. Reading the old DS 1 manual it appears that the gooseneck was designed to allow one to reef the main by pulling the boom out a bit (to the round part) and then furling the main sail around the boom. Do people do this? Also, when I look at the goosnecks sold by D&R for the DS 1 they appear to have spring internal to the boom... I'm wondering if mine isn't just incomplete.

I'll stop there for now... but as the topic header implies I also have questions about boom-vang, down-haul, and/or cunninghams... none of which are present on my boat and I'm wondering if I need (any of) them. I'm guessing the boom-vang at least would help keep my boom snugged up to the mast?
Cheers!

Jon
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby GreenLake » Sat Aug 22, 2020 1:25 pm

Jon, I think you put your finger on it. The roller reefing around the boom would require a "reef claw" so you can attach the mainsheet to something when the main is wrapped around the boom. If your boat didn't come with one you can be pretty sure that nobody used this feature on your boat (and anecdotally from reading along on this forum, it seems very few people ever did).

With the sail firmly attached and the outhaul under tension, the boom won't go anywhere. The spring you mention isn't very strong (I may have pulled on mine once or twice out of curiosity). So I'm not sure that there's any immediate concern - as you suggest you could always rig a vang, that would really jam the boom against the mast. Having a vang is not a stupid idea for its own sake. I've held off from installing one for the longest, but now I really appreciate how you can use it to help depower your main: the vang will bend the mast, which pulls the middle of the sail flat, but it also puts tension on the leech and keeps the boom from rising as you let out the mainsheet. That maintains the flat shape of the main, even if you are not fully sheeted in, so you can let out the main to depower without the loss of shape undoing part of the effect.

You would need to rig something stronger than the 3:1 stock vang (which was ever only intended in keeping the boom low going downwind). I rigged a 6:1 with a 2:1 cascade, others have gone up to 20:1. You can search the forum for suggestions. Anyway, if you install one of those, your boom really won't go anywhere.

If you like the ability to reef the sail, put a slab reef in. Again, widely discussed here.

As for rolling the sail to stow it, I just put mine into a tight roll and keep it next to the boom (when parked - foot of sail in boom groove) or tied loosely to the boom when docked somewhere for a while, with the boom held up by the halyard. Not really any more work than trying to wrap a sail around the boom.

You would need a boom downhaul if the gooseneck can slide in the mast track. Yours seems secured with a screw. In that case, you'll have to tighten your main with the halyard. I do have a Cunningham for my sail, but it isn't always clear to me when and how to use it. Some days there are obvious wrinkles near the mast and adjusting the Cunningham fixes those, but there's less of an obvious pattern to it than I would have expected, so I don't feel I've mastered that one yet. Perhaps someone else can weigh in. In any case, you could watch for the telltale creases near the mast in the lower part of the main, and if, you could add a Cunningham - if your sail has the grommet for it (about 6" above the boom).

I'd say that of the items mentioned a vang might give you the biggest bang for your investment.
~ green ~ lake ~ ~
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby jalmeida51 » Sun Aug 23, 2020 12:38 am

When I come on hard with my boom vang I get scallops ( wrinkles ) in the luff of the mainsail. Getting rid of the scallops will improve the performance of the boat. To set the curvature of the sail you have to put more tension on the sail. The easiest way is to come in with the cunningham this will tightened up the luff and the scallops will disappear and you will get the correct set. If you don't have a cunningham you can try to tension the halyard or the downhaul. I never could get enough tension using the halyard or downhaul. If you have wrinkles at the foot of the sail you need to tension your outhaul.

To remove the scallops on the luff of the jib with hanks put tension on the halyard. I try to put tension on the jib with the boat facing into the wind. If you put too much tension on the jib halyard it is easier to ease off the halyard than increase tension when you are sailing.

If your sails are bagged out, you will never get them flat. You don't want a large draft ( bag ) when it gets windy and when you reef you want to get the sails flat as possible.
Happy Sailing, John
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby jboright » Sun Aug 23, 2020 3:05 pm

Thanks GreenLake and John for your thoughtful replies.

Before reading your suggestions, Greenlake, I went ahead and ordered the stock 3:1 vang from D&R. Hoping it'll help (at least a little) for the short term. I'll have to look up what the different configuration terminology means ('cascading' for example). Hopefully I can add to my 3:1 vang to get higher ratios?

Unfortunately, the fist slide on the main sail is so far above the gooseneck that, even with the sail fully attached to the boom and the out-haul tight, I can still easily slide the boom off of the gooseneck pin. Good to know that the boom vang will help... In the meantime (while waiting for my vang to arrive) I'm making do by binding (loosely) the sail to the mast by adding a loop of line around the mast and through the cunningham grommet (I'm sure there's a real name for that). This configuration seems to answer.

IMG_5554_small.jpg
Loop binding the sail to the mast.
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Cheers and thanks again!

Jon
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby GreenLake » Sun Aug 23, 2020 3:25 pm

Originally, the DS did not have sail slides; instead the boltrope on the luff of the main goes in the sail track. Some people find that cumbersome to use (I don't, particularly) and adopted a set of sliders instead; I've sailed on bigger boats where those are standard, but think they are overkill for the DS. But that's just my opinion. I sail with an eclectic bunch of small boat sailors none of whom are afraid of tinkering with their rigging, but none of them ever tried to retrofit sail slides. (The boats are all different, but in the size range of a DS). I guess, if kept on a mooring with the mainsail simply flaked to the boom and under a cover (like on the big boats), I can concede that it might buy you something over simply pulling the main out of the mast groove and rolling it. But for dry sailing?

Anyway, you do have the grommet for a cunningham, because that's what you are using for keeping your boom to the mast.

A 3:1 vang will help holding the boom forward - it's main downside is that you cannot adjust it when under load as with those with a higher purchase. You could rig a double (4:1) cascade, and that would give you an effective 12:1. Might work. Until then, you can just set it tight enough that the boom is held in, but not so tight that affects the sail shape when everything is slack. It would still keep the boom from rising much when you sail upwind or on a reach with the main loose. I don't think that's a bad thing compared to the boom coming off :)
~ green ~ lake ~ ~
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby tomodda » Sun Aug 23, 2020 7:29 pm

Hi Jon:

Answering your implied question, the hole in the luff that the cunningham goes thru is called the "Cringle", as in Cris. One of the funnier boat-related terms, right up there with Baggywrinkle and the Poop Deck :). All kidding aside, check out this website:

https://www.ronstan.us/marine5/vang_systems.asp

Pretty much every small-boat vang setup there is, conveniently indexed by how much Ronstan gear you need to buy to set it up (go figure). But the truth is that you don't need to use Ronstan blocks, just be aware that whatever you use should have a decent MWL (mean working load) to take what the boom is going to demand of it. The MWLs that Ronstan recommend on this website are a good "ballpark." For each block in my setup, I looked up the MWL on the Ronstan blocks they recommend and then got more or less the same thing for much cheaper via Ebay and/or Salvage Marine shops. But new works too, of course! And I used Dyneema rope in the cascade, no wire. Anyway, when you're ready to upgrade your vang, search around this forum, there's been numerous discussions on Vangs, blocks, and working loads.

Best,

Tom
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby GreenLake » Sun Aug 23, 2020 9:10 pm

Outside stays, wire has no place on small boats any longer. But you don't necessarily need Dyneema (AmSteel) as a replacement. A lot of other rope is thin and non-stretchy enough at the anticipated loads that you don't need to use Dyneema.

When designing a cascade, the rope for "outer" cascade will have to hold 1/2 of the total design load of the vang. If you have a dual cascade, the inner rope will have to hold 1/4. And the purchase has to hold either 1/2 or 1/4 depending into which type of cascade (2:1 or 4:1) it's integrated.

Now, for a 6:1, the rope in that purchase experiences 1/6th of the load on the purchase (a bit more due to internal friction, so let's say 1/5th). Translating to 1/10th or 1/20th of the design load for the vang. That rope can be sized rather thin, as long as you can find rope that is still grippy enough that you can pull on the tail with 1/10th or 1/20th of the design load. (Actually, the design load would have a safety factor for shock loads, but you wouldn't be adjusting your vang right then - the rope may have to hold 50lbs while you may need only 25lbs max to adjust it - one number figures into the MWL for the rope, the other into how small a rope you can grip: and different styles of rope construction or covers make a difference here).

Here's a picture:

2663

you can see that the blue line is rather knobbly - it's pretty grippy. The red/yellow line is a tad thicker, but I picked one that's really stiff - that reduces the tendency for the vang to turn into a hopeless tangle when not attached. I could have used Amsteel for the cascade part, because it's slipperiness wouldn't be an issue, but in the purchase, it would have been the wrong choice as it's hard to grip.
~ green ~ lake ~ ~
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby GreenLake » Sun Aug 23, 2020 9:21 pm

As you can see, I do use the Vang#8 in the link shared by Tom. I happen to use those Ronstan parts because they were carried by my local store. However, I've not been able to mount them the way they show in the diagram, because in that orientation, I can't pull on the line at an angle that allows cleating. So I mount the cascade upside down and cleat at the boom end. Generally, that's worked well for me. An alternative is to not use the integral cleat, lead the line on deck and to the back end of the cuddy and cleat it there. Other people bring it down to the CB trunk. The longer those lines run, the more stretchy everything gets, which is one of the reasons I haven't done that. On the other hand, there's a sailing technique (vang sheeting) that relies on rather frequent adjustments of the vang.

If I ever decide to change my setup, it wouldn't be difficult to do - one of the reasons I start with the simplest configuration is to make sure I gain enough experience with a control to know how I want to use it with my style of sailing.
~ green ~ lake ~ ~
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Re: DS 1 gooseneck, boom-vang and downhaul (?) configuration

Postby GreenLake » Sun Aug 23, 2020 9:23 pm

PS: Ronstan lists their design with 990lbs of MWL. That's entirely limited by the single block used in their cascade, as the blocks used in the purchase have 880lbs (and should therefore work in a cascade that can hold up ~1700 lbs). However, at that point you are probably capsizing. (You may also run into WL issues for the attachment points ...)
~ green ~ lake ~ ~
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