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EASLOOP

EASLOOP

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I have looked at the threads on boom preventers and the advice etc given there is top quality. Unfortunately with lack of expererience my ancient brain has great difficulty in assembling imagery from the written descriptions. Does anybody know where I can get some diagrams on the way to rig preventers are rigged etc?

My boat is a 28' wooden sloop.

Thanks
 
Thanks for your input. I had found that picture but I have roller reefing and so can only attach the preventer to the cockpit end of the boom where the swivel is. I had thought that once set up the preventer would work on either tack, but it seems that once the preventer had slowed up the boom swing it would need to be controlled by adjusting the preventer sheet on the appropriate side of the boat. The mainsheet traveller (horse in my case) can be left as is while the control of the boom is dealt with manually via the preventer sheets as it were. The preventer would need to be re-set on each tack. Is that about right?
 
I have never thought of the preventer as something to control the gybe, but as a safety precaution to prevent the boom coming over in the event of an accidental gybe. We release the preventer and then gybe normally using the mainsheet as the control. Then we set up the preventer on the other side.
In anything but the strongest winds I use my boomvang as a preventer, unclipping it from the base of the mast and clipping onto a strong point at the rail. This has the advantage of acting as a preventer and also puts the vang in the best place to haul the boom down. Works well for me, attracts howls of derision when I've mentioned it before on these fora!
 
G'day John,

Wen we owned a 28 foot mono hull, we had the preventer rigged from the aft end of the boom with the line running forward and down to a spring pulley then back to a clutch cleat within easy reach of the helm.

You will have to adjust the traveler, foot, leach and halyard tensions to get the best sail shape / performance.

Keep in mind that preventing the boom from gybing can be problem, we only ever had a single line and passed to the other block after tacking, this avoids the extra bits that seem to jam or tangle in the dark or when you don't need another problem.

Never leave the helm with a preventer in place in any sort of wind, it gets the heart racing when she gybes.

Avagoodweekend......
 
And now for the dumb question. With the boom out to the starboard side would the preventer be on the port side? Can't 'see' the forces involved. It appears as though the angles are all too acute so the forces are minimal.
 
I assume you mean roller reefing round the boom? If so you can rig a kicking strap using a boom claw and you could attach a preventer to that. I can't think of a way of having one preventer that would work on both tacks.

I wouldn't be inclined to use the preventer to control an intentional gibe, it is more a device to prevent a sudden uncontrolled gibe or to stop the boom flapping about in low winds. It isn't intended to be a substitute for the mainsheet which should remain the primary control for the boom and mainsail, although it could be used carefully to slow things down during an unintentional gibe.
 
Yes, I understand that a preventer would need to be rigged one on each side. But which preventer should I use when the boom is out to starboard and on its way across to the port side, the port one or the starboard.

I am trying not to be dense, but??
 
Yes, clearly the forces involved are huge, A couple of accidental gybes the other day in the lightest of airs (we were goose-winged) were quite frightening.

The more I ask and discuss the more clear the matter becomes.
 
[ QUOTE ]
Yes, I understand that a preventer would need to be rigged one on each side. But which preventer should I use when the boom is out to starboard and on its way across to the port side, the port one or the starboard.

[/ QUOTE ]

When the boom is to starboard it should be held by the preventer on the starboard side. When you intend to gibe, you should take control of the boom using the mainsheet, taking in on the mainsheet as you release the starboard preventer, going through the gibe and then letting the mainsheet out on the other tack. You can then set the preventer on the port side.

You can use the preventer in conjunction with the mainsheet to slow/control the gibe, but I wouldn't use it in isolation.
 
Being blunt.... without a purchase system on the preventer, and without the assistance of the mainsheet, you are pissing into the wind trying to control a gybe with it....... at best you'll get rope burns, and at worst, you'll break something or someone....
 
OK, so for a controlled gybe that all makes sense and in fact we had good control of the mainsail using the traveller. But will the stbd preventer slow up an accidental gybe when the boom wants to swing from stbd to port side in a rush?
 
[ QUOTE ]
OK, so for a controlled gybe that all makes sense and in fact we had good control of the mainsail using the traveller. But will the stbd preventer slow up an accidental gybe when the boom wants to swing from stbd to port side in a rush?

[/ QUOTE ]

It should stop it all together if you have made off the preventer as intended. But if you are going through a full gibe, with the main backing, you have to take control quickly by letting off the preventer and taking in with the mainsheet as the boom goes over. Not too drastic in light winds, but can be serious in stronger winds.

The preventer is only really there to prevent someone from getting an unexpected knock on the head and to give you a few seconds to take control of the unexpected - I would only use one in light wings on a longish downwind run, most probably when goose winged.
 
"will the stbd preventer slow up an accidental gybe when the boom wants to swing from stbd to port side in a rush?"

It'll either stop it entirely or something will give way, causing damage, and the boom will slam across.

To slow down an accidental gybe you need something like a boom brake or boom lock, but I don't think they can co-exist with a roller-reefing boom.
 
on a starboard tack you will have a preventer on the starboard. The forces involved on a gybe are not too great right at the beginning of a gybe- but become huge as the sail/boom swings over. The preventer should be rigged as not to let the boom actually start swinging. As said above the mainsheet should be the thing that controls the mainsail.
 
Thank you all for a most enlightening discussion. I now understand how the preventer works. it would seem that the best way to control a gybe is to be paying attention and control the gybe using the mainsheet. What I really need is the boom brake - but as has been said they do not fit onto roller reefing booms.

Thanks again
 
The "Dutchman" looks an interesting device- it also looks like it might be quite easy to make one, maybe using tufnol sheet for the sides and proprietry sheeves- any thoughts on this?
 
No, apparantly it cannot be used with a roller reefing boom like I have. I am going to put some more thought into alternatives using thick rubber brakes at the tension points.
 
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