Rigging a boom preventer, and gybing deliberately. Got it wrong.

[FairweatherDave]

Caused myself and crew a few problems yesterday. Approaching West Pole in a force 4 to 5 and lumpy following sea I had rigged a pole on the genoa and and a boom preventer to goosewing pretty much direct from Seaview. My preventer is simply a line fixed mid boom to midship cleat with an OXO.
MY plan was to turn onto a broad reach to enter Chichester by gybing the boat and slowly easing the mainsail accross using the preventer. Bad plan. I went up to the midship cleat and requested the helm to gybe. But I could not release the OXO with the way the line went up to the boom. Now we were on a reach with the boom on the wrong side, mainsail fully powered up. I would guess we had broached as the helm could not correct course at all. A little bit of reading around suggests we had headed up and were "pinned". Situation only rectified once we were able to get back more on a run and release the preventer.
In the circumstances what should I have done? Either remove the preventer in advance and then gybe the main. Or have a much improved preventer using some form of block attached to the midship cleat. Ideally with the line back to the cockpit too.
As an aside our mainsheet fixes at the end of the boom to the stern and can take out an unprepared helm in a gybe - so being able to ease the boom across was my intention. With no preventer I would normally centre the boom as far as possible before gybing , and then let out the mainsheet pretty quick once the boom has gone across. But my key question is about rigging a better preventer and if it can be used at all to slow the boom in a gybe.
Boat is a 29ft Westerly Konsort bilge keel. Very aware the wind would increase once no longer on a run but did not need the aggro with the preventer. But the pole and preventer had done a great job in quite a rolly sea up to the West Pole. Still got lots to learn.......

 

[[3889]]

The way to rig a preventer is with fairly elastic rope attached to the end of the boom and led forward as far as possible then aft to a cockpit control. It is not good practice to deliberately gybe with a preventer attached. Having done so it is time for the knife to come out. If you want a boom brake fit a boom brake though there is no reason your usual method will not enable a safe gybe, perhaps dampening the shock load on the mainsheet by paying it out in a timely way with a turn or 2 on a winch.

 

[stuartwineberg]

Not a great idea to rig the preventer mid boom. In extremis the preventer stops the middle of the boom moving but the end keeps going and snaps the boom. On my set up there is actually the word "preventer" cast into the loop at the end of the boom (Selden). As previous post says, take the line well forward (it goes through the loop of the forward cleat on my rig) and back- in my case to the lazy winch so it can be adjusted easily - I accept that wouldn't work if the boat was being goose winged. I also have a line rigged under the boom from the preventer loop to the mast with a loop in it so if I need to rig the preventer with the boom end already well outboard I don't need to hang over the side. I just attach the preventer line to the loop and let the lot go (hope that makes sense). Just come back from 400 miles round the West Country in mostly light airs and it was incredibly useful to stop the boom flogging back and forward on a very broad reach and light winds and a bit of a rolling swell.

 

[FairweatherDave]

Thanks both. The knife was considered. Both by myself and the helm. Different purposes I suspect.
I do follow your under boom line Stuart, thanks.
I read (after the event) about attaching to a forward cleat, makes complete sense (as does stretchier line).

 

[scottie]

If you are not able to control a gybe then tacking through the wind is I believe a great alternative

I learned to sail in a gaff cutter

 

[stuartwineberg]

Nice reaction to the posts - thank you. I wish everyone on the forum treated replies and observations so positively. Enjoy the rest of the season.

 

[dunedin]

As others have said, rig through the bow cleat not the stern cleat.
Also it is important to be able to release quickly in case need to take avoiding action. Ours is led back along the side deck to the stern cleat, beside the helm.
To gybe in a hurry we release the preventer from the stern and winch in the mainsheet as usual to make the gybe, ensuring the preventer can run free and sort it out after the gybe.
We have all borrowed these ideas from others we have sailed with or spoken to.

 

[FairweatherDave]

Cheers all. Love the forum! Learnt loads here. Going to have to find yet another long bit of rope. Not going to repeat what is now known in our family as "The West Pole incident"

 

[Poignard]

I rig two preventers, one each side. They lead forward inside the shrouds to the bow fairleads then back outside all to a position level level with the cockpit where they are attached to the guardrails with a snap-shackle until required. Attached to the extreme aft end of the boom is a single short strop, having a ring in its free end.

When I want to rig a preventer I unclip it from the guadrail and clip it to the ring on the strop. Then pay out the main sheet and take up the slack on the preventer, finally tightening it by hauling in the mainsheet as necessary.

To gybe I pay out the active preventer and haul in the mainsheet hard and unclip the preventer that has been in use. Then transfer the strop to the other preventer, gybe and tension the new preventer as before.

(takes longer to decribe than it does to do it! )

 

[LadyInBed]

With no preventer I would normally centre the boom as far as possible before gybing , and then let out the mainsheet pretty quick once the boom has gone across. But my key question is about rigging a better preventer and if it can be used at all to slow the boom in a gybe.

Even with a preventer why didn't you use your normal method?
It's a well tested method.

 

[Sgeir]

One long long line, both ends tied off at the boom and passed through a block at the foot of the foresail does it for us - pull in the slack to the windward side where we control it on a self tailing winch.

This setup allows a controlled gybe. Best with two people, one for the preventer, one on the wheel/tiller. But can, with forethought and preparation, be managed solo.

 

[FairweatherDave]

Even with a preventer why didn't you use your normal method?
It's a well tested method.

Good question. The circumstances were rolly. It had been quite hard just to hold course without full concentration. Given I was under the delusion I could dampen the gybe from the midship cleat and would have to go forward and release the preventer anyhow I thought I could kill two birds with one stone.

 

[FairweatherDave]

Dampening using a winch is not something I have used before, or at least it hasn't sprung to mind when it should have. Not enough sailing.....

 

[Biggles Wader]

One long long line, both ends tied off at the boom and passed through a block at the foot of the foresail does it for us - pull in the slack to the windward side where we control it on a self tailing winch.

This setup allows a controlled gybe. Best with two people, one for the preventer, one on the wheel/tiller. But can, with forethought and preparation, be managed solo.

That is the most appalling diagram but you are excused detention because it is actually a very good way to manage the problem:encouragement:

 

[rogerthebodger]

One long long line, both ends tied off at the boom and passed through a block at the foot of the foresail does it for us - pull in the slack to the windward side where we control it on a self tailing winch.

This setup allows a controlled gybe. Best with two people, one for the preventer, one on the wheel/tiller. But can, with forethought and preparation, be managed solo.

I have a very similar setup except I have a large snap shackle at each end of the preventer so I can remove the lazy line so it does not trail across the cockpit.

before the gybe I release the preventer from the winch/cleat, then during the gybe I centre the boom and change the preventer line and cleat off on the winch.

 

[john_q]

I rig two preventers, one each side. They lead forward inside the shrouds to the bow fairleads then back outside all to a position level level with the cockpit where they are attached to the guardrails with a snap-shackle until required. Attached to the extreme aft end of the boom is a single short strop, having a ring in its free end.

When I want to rig a preventer I unclip it from the guadrail and clip it to the ring on the strop. Then pay out the main sheet and take up the slack on the preventer, finally tightening it by hauling in the mainsheet as necessary.

To gybe I pay out the active preventer and haul in the mainsheet hard and unclip the preventer that has been in use. Then transfer the strop to the other preventer, gybe and tension the new preventer as before.

(takes longer to decribe than it does to do it! )

+ 1 exactly what we do. The preventers are rigged permanently so easy to use and also I use one to hold the boom out to avoid shade on the solars on top of the wheelhouse roof at anchor

 

[FairweatherDave]

Apologies for pushing this. I'm not 100% clear. Does anyone use a proper preventer to dampen / control the gybe. I will certainly be setting up a proper preventer on the boom whatever but using it as a damper in the gybe might suggest a rope diameter kinder to the hands. Diameter suggestions also welcome. Mainsail is 16.7m sq

 

[Daverw]

Not sure why you would when you can use the main sheet to tame the gybe anyway, having the boom quickly swap over like I would in my dinghy days is not something I would like to do now on our yacht,

 

[Frank Holden]

No... I don't use a preventer to dampen the gybe..... if trying to do that I imagine the angle subtended ( I think that's the word ) between boom and preventer would reduce to such a degree as to render it useless.
I use a preventer ( from end of boom to turning block well frd and back to cockpit.... its designed purpose is as a spin pole downhaul so always ready to go ) to ****prevent**** the boom from moving.

I always use a very conservative amount of main which makes the next bit easier.....

When I want to gybe I bring the wind around a bit from right aft to maybe 20º on the quarter... depends on the sea state... then ease to preventer while cranking in the main sheet so boom is almost on the centre line.... disconnect working preventer.... connect new preventer .

Then helm down ( or up - depending on which side you dress )..... as soon as the wind is across the stern and wind on other side of mainsail ease the main sheet while hauling in the preventer.

 

[Nimrod18]

I've used 2 systems for preventing.

(1) a line (sometimes a tackle with a snap shackle) led from mid boom (sometimes the eye where the kicker attaches) to turn around a leeward centre cleat or snap onto the shroud base fitting but then back to a cockpit cleat.

Or (2) a line clipped to a boom-end strop that then runs around a forward cleat or fair lead and (dependent on the boat) back to the cockpit on the windward or leeward side.

In my opinion, the advantages of (1) are that:

(a). It will definitely stop the boom moving across the cockpit.

(b). It is easy to swap over following a gybe - unclip it from the (new) windward fittings, pop it over the coach roof onto the (new) leeward fittings.

(c). If the boat accidentally gybes, then the preventer cleat is on the (new) windward and uphill side and easy to tend. Can be useful if you're pinned hard over and the (new) leeward side is a bit 'damp'.

The disadvantage of (1), as another contributor stated is that, in a rolly polly sea, you might bend the boom if you dip it. I will mention that I've never personally dipped a boom, but I know it is a possibility.

The advantage of (2) is that, in a rolly polly sea, the preventer will stretch a bit and should reduce the chance or prevent boom damage.

However the disadvantages of (2) are that:

(a). The angle between the boom and the preventer rope is less orthogonal. From what I have observed the boom usually moves to at least the centreline of the boat before rope tension really builds and the boom is meaningfully 'prevented' - this even if the rope is sweated puckah tight during the set up. Ergo, damage to noggins may still result, though hopefully to a lesser degree. Obviously a lot here depends on the initial boom angle, and therefore point of sail. For those who use system (2) it's worth a 'trial' accidental gybe in a decent blow to check your system's effectiveness.

(b). It can be a pain to re-rig, involving a trip to the foredeck and end-over-ending the rope, unless there is a clip for the strop on both ends, or you are employing the rather neat system drawn up by a couple of comments above.

(c). If the return line for the preventer crosses from the leeward bow to the windward and returns to the cockpit along the windward side, following an accidental gybe will be on the (new) leeward side of the cockpit which, dependent on conditions and the degree to which you are 'pinned', may now be a little 'damp'.

In sum there are pros and cons to each.

For that reason I tend to use system (1) if I'm in generally sheltered waters with a beginner crew - no risk of dipping the boom, short trips to the coach roof, easy rope work if there's lots of manoeuvring to be had and, most importantly, the boom doesn't budge during an accidental gybe. I tend to use system (2) if I'm on a coastal passage because of the potential to dip the boom, the less frequent requirement to gybe (and therefore re-rig) and the likelihood that the crew will have a bit more sea sense by then. All boats are different, so none of my views should be treated as black and white.

My key points to the OP are that:

(a). Whatever system you use, bring it back aft to the cockpit - cleat or winch - so you can ditch in when you need or, more correctly, ease the boom across under control after an accidental gybe (to that end, suggest make sure the rope's long enough to do the latter).

(b). As previously observed, I'd have it slack and free to run immediately after the "standby to gybe" <or whatever terminology you employ> command. The friction in the main sheet blocks is all I've ever needed for controlling the runout of the main boom after a gybe.

Great thread and well done OP on thinking about keeping your crew safe.