Vang as preventer?

[Alisagc]

we have an 1978 O'Day 25, rogged with a boom vang. Having done some research on preeventer rigging, it seems some folks use the vang as the protector, especially in smaller boats.

Would love to hear from forum if this is feasible, and if so, whats your setup.

Thanks,

Alisa

 

[justsomeguy]

I have used the excess line from my soft vang as a preventer, but only in light, flukey winds. If there was more of a blow, I'd rig a line from the boom end going forward around a stanchion base then back to the cockpit.

 

[David in Sandusky]

Our vang has snap shackles at both ends, and enough line to allow two preventer configurations:

1. For waves below 3 feet - low chance of the boom end going in the water. Unsnap bottom end of the Vang at reattach forward at the toerail or stanchion base.

2. Waves over 3 feet. Chance of the boom end dipping into the water, and huge bending force if the top of the Vang is at normal position, close to the mast. Detach both ends of Vang. Top end to end os boom, bottom end forward to toe rail or stanchion base.

This is a cruising rig. I wouldn’t rig a preventer if I were racing.

 

[Ron20324]

I installed snap shackles at both ends of the rope vang. Also installed a shackle at the lower end of the mainsheet, at the traveler. I have two preventers or to hoist things out of the water. Also installed a boom bail at the aft end of the boom to add to the multiple use of the gear.

 

[Rick D]

When I used to sail my Thunderbird (26') solo, I rigged my vang with a snap shackle at the mast base and put two eyes at the rails, port and starboard, and simply ran the end of the vang out to the eye. Yea, I know all about going to the boom end, blah blah. I didn't and all was good for 19 years. The only exciting times were when when I had to take it off in 20-25 knot winds!

 

[LeeandRick]

From your pictures (what pictures ? ) there may be a snap shackle at the mast end of the 4:1 section of the cascade, if not add one. You just disconnect from the hard vang tube and connect it to a stanchion. I don't like connecting to stanchions so I would put a D shackle at the base of the lower shroud. The only concern would be the angle the line comes off the sheave at the boom since the tube section of the vang probably does not rotate.

 

[Stu Jackson]

I'm with Rick on this one.

However, when using a preventer is usually when you have the boom out, which is exactly the time you want and need your boom vang. While it seems easy to use the vang, I felt it was too much sail control to lose, so I put a snap shackle on the bottom of my cunningham, which allowed me the use of the vang all the time. 13 years on a Catalina 25.

 

[RussC]

I like having a dedicated system. the coil of red line is our preventer, and it stays at the ready. a quick clip on one end clips into the end of the boom, wile and a cam cleat on the cabin top controls the set and release end. the forward portion of the line is in a small eye block near the base of the forward stanchion. Can be set or released in seconds.
I just have one on the port side, but I only use it when DDW and always set as shown anyway. easy enough to put one on the starboard side also if desired.

 

[Roland5048]

IMO using the vang as a preventer would not be recommended except in the lightest of air. The reason being that in the event of an accidental gybe this places the fulcrum too close to the mast. This gives the wind a lot of leverage to bend the boom. If attached to the end of the boom this eliminates the leverage effect. Think moving a heavy object with a lever, say an 8 ft. 2x4. You place the fulcrum close to the object to be moved giving you a lot of leverage on the long end. You would never move that heavy object with the fulcrum far from the object.

 

[David in Sandusky]

When you tighten a preventer, both the preventer and mainsheet are pulling down, while offsetting each other fore and aft. As a result, the preventer and mainsheet together act as a vang, pulling the boom end down. And, the effect is easily controlled with the mainsheet.

Roland, I addressed the boom end in the water. Our boat is plenty stable in 3 footers to be sure of keeping the boom end out of the water. Above that, I rig the Vang to the boom end. I trust Rick’s judgement that this is not a problem on his boat.

 

[Will Gilmore]

Doesn't the preventer act as a vang under the conditions when you would need a preventer, variable winds, rolling seas. You want the sail to belly and the boom to lift a little anyway.

- Will (Dragonfly)