Boom Preventer

[jaminb]

After watching Sam Holmes lastest video I have decided to rig a permanent boom preventer.

I did make a boom brake using a climbing figure of 8 belay but wasnt convinced as it only reached back to the mid point of boom and I thought it should be fitted as far aft as possible.

So i was thinking permanently install lines from the boom end either side of the boom held tight with elastic at the goose neck end. This would then attach to a non permanent line rigged through the bow mooring cleat on the appropriate side and then run back to the aft mooring cleat so it could be easily released when required.

However another though occurred, could I use the spinnaker pole down haul attached to the permanently installed lines? Would it be sufficiently strong (AWB bolted through the deck but behind a head lining). Obviously I would need to rig the non permanent line if the spinny was in use but this wouldnt be the case when the wind was strong and one less line to rig may be preferable in windy conditions.

Silly idea or worth pursuing? Thanks

 

[B27]

I'm not sure how strong a preventer needs to be.
We experimented a bit with preventers this year, because we often seem to end up wanting to dead run along the coast.
If your preventer is very very strong, something has to give if the boat accidentally gybes going down a wave.
Or if you broach and dip the clew in the water?

I rig the preventer with a weak link. The block on the foredeck is tied on with line which will hopefully break before anything expensive.
Mostly we prefer to head up a bit, the boat is under better control, rolls less and makes much the same progress.

 

[Ningaloo]

I also had a trial this summer with a climbing figure of eight and decided to keep it, despite only being attached half way along the boom.
It was effective in slowing intentional (and one unintended) gybes and also useful to stop the boom swinging when motoring once the sail has been dropped.

 

[Kelpie]

We have a dyneema line permanently mounted on the boom, from the outhaul end to a hook near the gooseneck. The hook is on a length of bungee so when stowed, the preventer is held tight August the boom and doesn't sag down.
We add an extra length of rope to it in use, which extends the preventer and allowed it to be led up front, through a block on the rail, and back to the cockpit.

We use it a lot. If we expect to be on a run for more than about half an hour, the preventer goes on. It's just so much less stressful. Having the permanent line attached means all the work happens at the mast, no wrestling with the end of the boom. Been there, done that.

 

[B27]

I sailed on a boat with some sort of boom brake arrangement, absolutely horrible, made it very hard work to gybe the boat properly.
Our 'solution' was made more complex by having the dinghy on the foredeck.

 

[Sandy]

Boom brakes are the work of the devil.

On a downwind passage rig up two lines to the port and starboard forward cleats that are run back along the deck towards the stern. A convenient preventer is then at hand. Little chance of being slowly clouted on the head and the lines can be used for other purposes like tying up on a pontoon.

 

[rogerthebodger]

Do you mead a boom control device or a gybe preventer.

My gybe preventer is a line that runs from a snatch block on my bow fitting to each side of the cockpit next to the boom end with a big snap shackle on each end that can the attached to the boom end depending on which gybe you are on with the other end cleared off ready to release if necessary

A boom control is a line that passes through a friction device attached to the boom with a line attached to one side next to the boom control and cleated off at the cockpit to control the friction

This is my boom control device without the linerigged

https://flic.kr/p/2hB477p

 

[Refueler]

I'm not sure how strong a preventer needs to be.
We experimented a bit with preventers this year, because we often seem to end up wanting to dead run along the coast.
If your preventer is very very strong, something has to give if the boat accidentally gybes going down a wave.
Or if you broach and dip the clew in the water?

I rig the preventer with a weak link. The block on the foredeck is tied on with line which will hopefully break before anything expensive.
Mostly we prefer to head up a bit, the boat is under better control, rolls less and makes much the same progress.

My preventer is a light line with plastic clip .... the clip distorts and unclips in event of 'event' - stopping any damage to boat.

 

[billyfish]

You lucky ba--starts. Always hard on the nose whatever way I go. Running . Stuff of dreams.

 

[dgadee]

I have a Dutchman (bought while on work trip to US). Nothing negative to say about it, except UK price.

 

[Kelpie]

My preventer is a light line with plastic clip .... the clip distorts and unclips in event of 'event' - stopping any damage to boat.

Interesting. I didn't give it much thought but I assumed that the preventer should be taut and strong.
What sort of damage do you think would happen if the sail was suddenly backed, or the boom dipped? I'd expected that the boat would be spun around, but maybe I'm being naive.

 

[B27]

You lucky ba--starts. Always hard on the nose whatever way I go. Running . Stuff of dreams.

Running gets stale after a while, what happened to all the beam reaches the forecasts promised?

 

[morgandlm]

I have tried several boom brakes including the figure of eight type and really couldn't get along with them. I now have a line permanently attached from the outer end of the boom and secured near the gooseneck. I then have a demountable block and long line that I fix to a strong point on the foredeck. With the boom out to run before the wind I fix the forward end of preventer to the end of the line and carry the other end of the line back to the cockpit where it is pulled tight and cleated off. This stops accidental gybes, allows you to sail cautiously "by the lee" a little. In the event you need to gybe the line can be released from the cockpit, the gybe completed normally and the lines tidied up afterwards. The preventer is particularly important when in a rolling sea when the downwind course is difficult to control - especially when using the auto helm. So far it's worked for me.
David Morgan

 

[fredrussell]

A few mentions on this thread of preventers with weak link added. To my mind you then have a preventer that won’t prevent much!

 

[RupertW]

A few mentions on this thread of preventers with weak link added. To my mind you then have a preventer that won’t prevent much!

It should delay and damp a gybe especially in light but if it’s a violent gybe you really don’t want a broken boom or mast while the preventer hangs on. Thats why a mid boom position is potentially so damaging if the preventer is too strong.

 

[Refueler]

A few mentions on this thread of preventers with weak link added. To my mind you then have a preventer that won’t prevent much!

IMHO - I am looking for a DELAY to the boom action ... such that I can do anything I can to lessen effects.

Its not like a Derrick preventer - which must be strong and hold the derrick.

 

[Stemar]

On Jissel, I had a line permanently rigged with a snap shackle at one end, that was clipped onto the pushpit, forward outside everything to a block at the bow, then back to a cleat on the pushpit. As a preventer, I'd simple attach the shackle to the end of the boom and take up as much slack as needed before cleating off again. The big advantage was that I could release it from the cockpit, though I'd still have to go forward to reroute it round the mast after a gybe. It was also a real help picking up the mooring in windy weather, as I could grab the pennant from the cockpit and attach the line, so I'm safely attached, and I could take up the slack at leisure, as the gusts allow.

 

[Kelpie]

A few mentions on this thread of preventers with weak link added. To my mind you then have a preventer that won’t prevent much!

I think this is genuinely a conversation worth having.
My preventer is not intended to break. I'm going entirely on intuition but I think I'd prefer a backed mainsail to a crash gybe.
Our boat is centre cockpit, with the mainsheet aft. An uncontrolled gybe has the potential to injure people in the cockpit, or to sweep them overboard. Not to mention the rig damage from the boom potentially slamming in to the shrouds.
In contrast, wouldn't a backed mainsail simply spin the boat around until you ended up hove to? Even dipping the end of the boom in a wave crest might not be that bad, it would just slow you down.

The times when our preventer has earned its keep, it's always been rather undramatic- mainsail backs, boat starts to slow and turn, I reach for the wheel and get us back on course.

Does anybody have examples of accidental gybes in really strong conditions, where a preventer led to rig damage?

 

[scozzy]

A block P & Std at bow attached to most forward pulpit supports.
Shackled SS carabiner on end of boom.Line with bowline knot either end around everything via blocks forward to stern cleats P& Std.
Easy peasey to engage/disengage by simply clipping line onto carabiner and trimming and cleating off on windward side,right next to where im sitting,if block failure forward you still have second pulpit supports to offer a secondary barrier before anything too disastrous occurs.has multiple uses when not in use.To gybe,bring main into central position, unclip and repeat on new tack

 

[flaming]

I think this is genuinely a conversation worth having.
My preventer is not intended to break. I'm going entirely on intuition but I think I'd prefer a backed mainsail to a crash gybe.
Our boat is centre cockpit, with the mainsheet aft. An uncontrolled gybe has the potential to injure people in the cockpit, or to sweep them overboard. Not to mention the rig damage from the boom potentially slamming in to the shrouds.
In contrast, wouldn't a backed mainsail simply spin the boat around until you ended up hove to? Even dipping the end of the boom in a wave crest might not be that bad, it would just slow you down.

The times when our preventer has earned its keep, it's always been rather undramatic- mainsail backs, boat starts to slow and turn, I reach for the wheel and get us back on course.

Does anybody have examples of accidental gybes in really strong conditions, where a preventer led to rig damage?

Dad put one of those Scott Boomlock things on one boat.

Nice idea, but the problem with it was that the locking part allowed the boom to swing some distance before it stopped it. So it built up quite a bit of inertia. And yep, one gybe the inevitable happened and the boom just folded in two at the boom lock.

The next boat we went for the same sort of system as has been described here, i.e a line from the end of the boom stored at the gooseneck that you then attached to a line that lead through a block on the foredeck back to the clutches on the coachroof. This was very good, and the only upgrade we did was to revert to solid pin blocks rather than the harken high tech ones after one disintegrated.

I think the key point is that when you put a preventer on it should be 2 things.
1. Attached at the end of the boom.
2. Hauled tight so that the boom is not allowed to pick up any momentum should the sail gybe.