Boom vang as preventer

Moderator: GreenLake

Boom vang as preventer

Postby flandersfrank » Sat Nov 22, 2014 12:18 pm

I just purchased a 1971 DS 1 and will be sailing it next summer on the eastern end of Lake Ontario. ( can't wait!,!) It's quite gusty and windy there and it makes sense to have some kind of preventer for downwind . Where would a boom vang attach to the deck for that purpose? I have a tabernacle mast if that is an issue. A would a 3:1 or 4:1 BV be sufficient? I will be pleasure sailing, not racing.
Thanks and enjoy ya wonderful thanksgiving
flandersfrank
 
Posts: 6
Joined: Fri Nov 21, 2014 11:31 am
Location: Jax,Fl

Re: Boom vang as preventer

Postby TIM WEBB » Sat Nov 22, 2014 1:29 pm

Since the vang stays anchored to the mast hinge bail, I installed this eyestrap/twist shackle/snap shackle to the boom. Can be used on either side, and the lanyard makes for a quick one-handed release. After some practice I was able to snap it on with one hand as well ...

1891

1892
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
TIM WEBB
 
Posts: 1208
Joined: Wed May 18, 2005 10:28 pm
Location: RIVERSIDE, CA

Re: Boom vang as preventer

Postby flandersfrank » Sun Nov 23, 2014 10:40 am

Thanks Tim

Neat idea

If I understand this correctly (pics were a great help) the vang keeps the boom "down" and the snap shackle clips to the side stay. Does that put any undo force on the stay?

Frank
flandersfrank
 
Posts: 6
Joined: Fri Nov 21, 2014 11:31 am
Location: Jax,Fl

Re: Boom vang as preventer

Postby TIM WEBB » Sun Nov 23, 2014 5:38 pm

No prob - thanks.

Yes, it's clipped to the shroud/sidestay (I put that in the comments in the gallery, but forgot to say it in the message). Vang is "on", and keeps the boom from "skying". When I use the preventer, or anytime the boom is out like this, I always make sure it's sheeted in just a tad, to keep it from contacting the shroud. Just until the snap goes "unslack", but is not pulling on the shroud. PO obviously did not do this (as evidenced by the scratch marks on the boom), even though there was no vang or preventer on it then. It was dead calm when I took the pics, so the sheet is slack.

The few times I've had the main backwind on me were all in fairly stiff breezes, with no harm done to the shroud, since it's so easy to quickly unclip it. The shrouds are the upgraded/thicker ones, and if they are strong enough for the other loads on them I should think they are strong enough for this. However, thinking about it more now, just in case, I may re-assess the system, and make it something that anchors to either the chainplates, or to eyestraps I now have just foreward of the CPs, that are currently only used for the boom tent. Hmmm ... ?
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
TIM WEBB
 
Posts: 1208
Joined: Wed May 18, 2005 10:28 pm
Location: RIVERSIDE, CA

Re: Boom vang as preventer

Postby itguy1010 » Sun May 01, 2016 7:39 am

TIM WEBB wrote:The few times I've had the main backwind on me were all in fairly stiff breezes, with no harm done to the shroud, since it's so easy to quickly unclip it. The shrouds are the upgraded/thicker ones, and if they are strong enough for the other loads on them I should think they are strong enough for this. However, thinking about it more now, just in case, I may re-assess the system, and make it something that anchors to either the chainplates, or to eyestraps I now have just foreward of the CPs, that are currently only used for the boom tent. Hmmm ... ?


Just curious Tim, if you've had any more thoughts or changes to your preventer system to share. I've been giving this idea of a preventer for long downwind legs some thought. Although it may handle the loads in cases of backwinding the main, I feel a little uncertain about the extra force placed on the standing rigging. Sure, one shroud could handle it especially if its the newer 1/8" type. And, even a healthy chainplate should be ok too I guess. But what about the overall additional load to the rest of the rig? I did a search on "preventer" to see what the prevailing solution was since I couldn't come up with anyplace on my DS2 where I would feel good about tying the boom end to.

So, what I'm now considering is adding a small horn cleat on each side of the deck just foreword of the shrouds specifically for this purpose. My problem is that I'm pretty sure there's no easy access to the underside of the deck in that area to secure a backing plate and fasteners.

Sitting here in the kitchen I'm trying to visualize maybe having a line coming from the main cleat on the foredeck with a snap on the end to attach to the boom as a preventer. It would have to be an anchor point further inboard on the boom since reaching the boom end would be rather difficult without going swimming.

Thoughts? Ideas?
Eric White
The "Jackie Beck"
73 DSII #6428
itguy1010
 
Posts: 79
Joined: Mon Aug 11, 2014 7:52 pm
Location: Brighton, Michigan USA

Re: Boom vang as preventer

Postby GreenLake » Sun May 01, 2016 2:02 pm

The advantage of Tim's system is how quickly it can be disconnected.

Leading a preventer to the end of the boom isn't necessary.

If you felt more comfortable having them tied to some point on deck, then you could combine the best of both systems by having an eye on deck, to which you tie a fixed line ending in a snapshackle. When you want to secure the boom, you pick up the shackle and connect it to a suitable point on the boom, perhaps a U bail. When you want to gypbe, just pull the toggle on the shackle. Downside is you have the unused preventer line lying around.

I would definitely not recommend something like a horn cleat on deck where you have to reach forward and fiddle tying/untying it.

On an older DS1, the underside of the deck should be accessible from the cuddy, so it should be easy to strenghten it with a backing plate to take the load from the fitting.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Boom vang as preventer

Postby TIM WEBB » Mon May 02, 2016 9:42 am

Honestly Eric, I haven't really given the preventer much more thought, probably because I hardly ever use it. The few times I've had the main backwind with the preventer on have been in light, fluky winds, and it was easy enough to quickly release it. Didn't stress the shroud at all. I don't use it in higher winds, in fact I don't really like to wing 'n' wing in higher winds.

Your idea of a line back from a foredeck cleat would probably work. GL's idea sounds like a good alternative as well, and he's correct in that the preventer doesn't need to reach the boom end. My boom tent eyestraps are through bolted to the rubrail in the same fashion as the chainplates. TRW also came with two small horn cleats mounted to the deck just inboard of the chainplates, and the backings for those are accessible inside the cuddy. As GL also states, the key is to be able to quickly release it, whatever you end up using.
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
TIM WEBB
 
Posts: 1208
Joined: Wed May 18, 2005 10:28 pm
Location: RIVERSIDE, CA

Re: Boom vang as preventer

Postby itguy1010 » Tue May 03, 2016 10:55 am

TIM WEBB wrote:Honestly Eric, I haven't really given the preventer much more thought, probably because I hardly ever use it. The few times I've had the main backwind with the preventer on have been in light, fluky winds, and it was easy enough to quickly release it. Didn't stress the shroud at all. I don't use it in higher winds, in fact I don't really like to wing 'n' wing in higher winds.

Your idea of a line back from a foredeck cleat would probably work. GL's idea sounds like a good alternative as well, and he's correct in that the preventer doesn't need to reach the boom end. My boom tent eyestraps are through bolted to the rubrail in the same fashion as the chainplates. TRW also came with two small horn cleats mounted to the deck just inboard of the chainplates, and the backings for those are accessible inside the cuddy. As GL also states, the key is to be able to quickly release it, whatever you end up using.


As always, I appreciate the help. Just for clarification, I posted in this DS1 thread only because it was relevant to my own questions about setting up a preventer. As my signature indicates, I only have the one DS2 (yet? thankfully? still happily married?).

My questions and thoughts about rigging a preventer began when I started studying larger boat handling on coastal and offshore cruises. This summer I really want to push my sailing skills out of my comfort zone and explore more offwind techniques. I'm thinking about a lot of reaches and runs both wing'n'wing or with spinnaker. Everything I had been reading and watching said that rigging a preventer on long downwind legs is a good idea. Plus, I want to get on some bigger water with my boat and in bigger air. Last year I was content to just pop the spinnaker out of the bag in light air. Fine for learning the procedures and such but not great for learning the finer points of sail trim, gybes, broach detection and avoidance etc.

So, although I may not actually rig a preventer (because the base of my mast and top of the cuddy are becoming really crowded with lines) I would like to have a solid plan for rigging one without too much difficulty should I chose to put one up. Whatever I end up doing though will have to have a quick release toggle snap or something easy to disconnect in a hurry and I have a few ideas for that. I have an upcoming trip to Traverse City, MI for a week with the wife and our boat. I really want to get out on Grand Traverse Bay with the DS2 and test my mettle and seamanship skills. Very, very excited about the trip.

Thanks again for the help.
Eric White
The "Jackie Beck"
73 DSII #6428
itguy1010
 
Posts: 79
Joined: Mon Aug 11, 2014 7:52 pm
Location: Brighton, Michigan USA

Re: Boom vang as preventer

Postby GreenLake » Tue May 03, 2016 1:11 pm

itguy1010 wrote:Just for clarification, I posted in this DS1 thread only because it was relevant to my own questions about setting up a preventer. As my signature indicates, I only have the one DS2 (yet? thankfully? still happily married?).


A good reminder that this thread belongs under "Rigging" - it's now moved.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Boom vang as preventer

Postby talbot » Wed May 04, 2016 5:43 pm

I have never used a preventer, but why not just put a low-profile eyestrap through the curled deck/hull joint, the same structure that supports the chain plates? It is easy to reinforce the lip (which is good, because DS II chainplates sometimes pull through). Once you have the eyestrap in place, you could have any of several quick-release connections to the boom, such as a spring shackle or even a line with with a slip knot.

It might even be possible to place the deck eyestrap where it can serve double duty as a foredeck bungee / jackline / springline connector.
talbot
 
Posts: 785
Joined: Mon Sep 03, 2007 3:37 pm
Location: Eugene, Oregon

Re: Boom vang as preventer

Postby TIM WEBB » Wed May 04, 2016 7:23 pm

I think I'll change TRW's preventer to utilize the boom tent eyestraps. Just seems to be a better solution ...
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
TIM WEBB
 
Posts: 1208
Joined: Wed May 18, 2005 10:28 pm
Location: RIVERSIDE, CA


Return to Rigging

Who is online

Users browsing this forum: No registered users and 11 guests