Boomvang

[occasion]

Has anyone installed a boomvang? Suggestions?

Thank you.
Sandy Burton
Occasion #368
Fairport, NY

[trashpad]

Not us but I think Dan installed a Dutchman Brake. I have rigged a soft vang several times and felt it did help but not as much as it did on the old monohulls I raced on.

[Ron]

The Dutchman Brake is more of a preventer than a vang. The traveller can be used as a near-vang and it should be just about your main control for the sail's angle of attack anyway. There was also a rumor on the 1st forum that Tony or Neil thought that the boom's extrusion and/or sliding bails attached to the bottom track may not be strong enough to handle that kind of load. A few of the guys were thinking about it, not sure if anyone ever did it though.

My own feelings are that you don't really want to run that far downwind on a trimaran anyway, and a good traveller system can almost take the place of the vang on your better points of sail. If I thought I really needed it, I would prefer a solid vang over a block and tackle, but that would create a lot more work when you wanted to lower or raise the mast. Modify your traveller for line control instead, and use it.

[occasion]

I was thinking that I could possibly get better sail trim if I could pull the boom down more. When out too far the sail rubs on the spreader. I was theorizing that with a boomvang I could get the sail out further and not rub against the spreader. Opinions?

Sandy

[Ron]

I was theorizing that with a boomvang I could get the sail out further and not rub against the spreader. Opinions?
Sandy

Sandy -

It might help in higher winds speeds, but you don't really want to pull the boom all of the way down in light air. Assuming you have the room (and you obviously won't in a narrow channel), it would help even more if you sailed a drop higher. Boat will go faster and you'll make it to the next waypoint quicker. I tend to use the traveller a lot in these situations too - moving it all of the way out will almost turn the sheet into a vang.

But I do remember something about Will, Tony or Neil saying that the boom hardware will not support these loads. Could be true, not sure. It would probably be hard to find the room for a hard vang too. The base of the mast is on the crowded side.

One compromise would be to rig something like Kurt described when needed - a soft vang between the boom and ?? It would do double duty as a preventer as well. I've been seriously thinking about mounting about 4 to 5 feet of T-rail on the top of the ama coaming. Could use it for cleats, barber haulers, preventers, vangs, spinnaker and screecher leads, etc. I miss having a rail out there.

[occasion]

Ron,
I like the idea of a t-rail on the alma coaming. I was only considering a soft vang, since the topping lift works fine to keep the boom up. Thank you for you comments.

Sandy

[wingman]

Well, I did rig a boom vang for just the reason mentioned. with the traveller down and sailing at 120 to 140 degrees under spinnaker, I did not like the shape of the sail. it was too twisted and hit the spreaders, though I did put covers on the spreader tips to reduce any rubbing damage.

I used an my old Prindle 18 mainsheet, which is probably overkill, but the price was right. My connection at the mast is to horizontally aligned U bracket attached to the vertical plate just aft of the mast. I used a fixed attachment bracket on the boom.

I did discuss with Neil and Tony the loads. I would worry if I wanted to use the vang on a reach, when the sail really loads up, but then the mainsheet works fine. I never crank down hard, as it is not necessary when going downwind. As we have a free foot and a relatively stiff mast, the vang cannot really do the sail shaping that you get on a smaller boat or with a more powerful vang. The real advantage is to reduce twist in light air.

As to the question do heating up by sailing higher, VMG does not lie. I get the best results sailing downwind more using the asymmetrical in light air and smooth water. In heavier air where we can do more with the helm to play the gusts and controlling heel to lift an ama, sailing higher works.

John

[simonhayes]

FWIW, I did have a conversation with US Spars about a boom vang and they were confident it would work and take the loads. Below is an old email I got from them with their suggestion, having looked at the Telstar 28 rig.

I never actually got around to doing this but it is on my list... . In the high winds where I sail, I feel the vang would keep the sail flatter and more controllable than the main-sheet/traveler combo alone. Then again, I need to get around to rigging control lines to the main-sheet traveler too. That is also on my list...



From: "Julian Crisp" <julian@usspars.com>
Date: December 10, 2007 2:06:55 PM PST
To: <simon@XXXX>
Subject: Vang

Hi Simon
Sorry for the delay but we are totally slammed to get everything out before the end of the year…

OK I looked at the Telstar vang and we can use our small rigid vang, we need to fit a bracket on the back of the mast 100mm above the sheave box for the raising system ,then fit a vang eye under the boom at 655mm from the end of the boom section. We also have a block and jammer system that’s installed on the vang which gives you a 16:1 purchase.
The total cost for the vang with purchase and the mast and boom attachments is $311.00

Let me know what you think.


Best Regards

Julian Crisp C E O
U.S.Spars, Inc
6320 NW 123 Place
Gainesville Florida 32653
Toll Free: 1800-928-0786
Local: 386-462-3760
Fax: 386-462-3448
Email: julian@usspars.com
Web: http://www.usspars.com



All information contained in this document is based purely on the information that US Spars has received from the sender. The information is given freely and should not be taken as factual, or as a recommendation of any action you should undertake. Any action taken by the recipient of this document is the sole responsibility of the recipient; US Spars takes no responsibility for the outcome of these actions. If you require a commitment of safe operation or are concerned about the integrity of any product whether made by US Spars or not you must enlist the services of a qualified marine surveyor. US Spars does not offer any advice on the condition of your spars or if they should continue in service so please do not ask. For this advice it is recommended to enlist a qualified marine surveyor.

[Ron]

I just wrote to Julian at US Spars, asking for some photos and details of the kit. If it looks good, maybe the association can get a break on the price (for members).

I'm a little concerned about the geometry. It may be too close to the forward end of the boom (26 inches plus the swing arm) to be effective. The loads would be very high at that point. Further out (maybe 1/3) usually works best, but the boom is too close to a point 4 inches above the raising system sheeve to get it there without losing the angle totally.

[simonhayes]

Ron,

Certainly keep me posted on what you hear... I would like to get one..

Are we still able to get the discounts on the traveler set up you put together ? I was looking for it on the Members benefits but couldn't see it

thanks