Trick to stop Topping Lift from Strumming

[photon]

Unless you have a Boom Crutch ( whats one of those?) you will often hear your topping lift humming as it is bearing the weight of your boom with tension also from mainsheet and kicker. The cause is turbulence in the wind passing over the halyard causing cavitation and thus vibration.

Slackening tension in the main sheet can reduce the resonance but at the cost of the boom slopping around in any rolling motion.

I have found a trick to damp the resonant frequency.

Support the boom and let off the topping lift to the maximum that your halyard allows at the mast. With a good hank of topping lift to hand simply wrap a spiral of 4mm cord around the topping lift maybe 20 turns or so extended down from the highest point accessible to the point of attachment to the boom securing both end with an appropriate knot or cable tie. Re-rig top the boom and enjoy a quiet glass of wine

The effect is dramatic.

 

[Goldie]

Unless you have a Boom Crutch ( whats one of those?) you will often hear your topping lift humming as it is bearing the weight of your boom with tension also from mainsheet and kicker. The cause is turbulence in the wind passing over the halyard causing cavitation and thus vibration.

Slackening tension in the main sheet can reduce the resonance but at the cost of the boom slopping around in any rolling motion.

I have found a trick to damp the resonant frequency.

Support the boom and let off the topping lift to the maximum that your halyard allows at the mast. With a good hank of topping lift to hand simply wrap a spiral of 4mm cord around the topping lift maybe 20 turns or so extended down from the highest point accessible to the point of attachment to the boom securing both end with an appropriate knot or cable tie. Re-rig top the boom and enjoy a quiet glass of wine

The effect is dramatic.

Or use your main halyard .

 

[[70521]]

My topping lift is the same diameter as the halyard, giving me a spare halyard, never been a problem.

I can't think why people use thinner line for topping lifts.

 

[KevinV]

Mine's three strand, which (like the proposed solution) sheds vortexes very well. Cheap too.

 

[MontyMariner]

It's not a problem that I've come across.

 

[Sea Change]

When we bought our previous boat it had a thin topping lift which would thrum away good style. I took to wrapping four turns of three main halyard round it and then shackling that to the end of the boom. If you always do the same number of turns in the same direction it becomes a habit and you can free up the halyard again without thinking about it.

 

[johnalison]

I would just slacken off the topping lift and tension the mainsheet against the rod kicker.

I think I have reported before how I replaced my TL with a thinner one, which was fine until it locked itself into a cleat for the leach line somewhere near the first reef, preventing the sail from being lowered properly. In the dark. In a rising wind. Just outside Ijmuiden.

 

[Sea Change]

I would just slacken off the topping lift and tension the mainsheet against the rod kicker.

I think I have reported before how I replaced my TL with a thinner one, which was fine until it locked itself into a cleat for the leach line somewhere near the first reef, preventing the sail from being lowered properly. In the dark. In a rising wind. Just outside Ijmuiden.

That's fine if you have a rod kicker...

 

[William_H]

On my little boat 21ft I have for many years habitually disconnected the topping lift and dropped the boom down on top the cabin top. It is constrained by winches. This means there is no pressure or movement on the main sheet or track so hopefully making it last longer. Previously I had to replace both the track and the car. The topping lift is only used when rigging or derigging the main sail. ol'will

 

[john_morris_uk]

When we bought our previous boat it had a thin topping lift which would thrum away good style. I took to wrapping four turns of three main halyard round it and then shackling that to the end of the boom. If you always do the same number of turns in the same direction it becomes a habit and you can free up the halyard again without thinking about it.

Almost exactly what we do. Easy peasy.

I like the ‘always four turns bit. I wrap a few turns and always have to look aloft when unravelling to check I’ve got it straight again.

 

[geem]

It's not a problem that I've come across.

Nor me. We don't have a topping lift

 

[fredrussell]

My topping lift is the same diameter as the halyard, giving me a spare halyard, never been a problem.

I can't think why people use thinner line for topping lifts.

Less weight aloft, I suppose. I’ve lost count of the boats I’ve seen using hoofing great halyards, topping lifts and reefing lines. I realise it’s for ease of handling, but thinner lines result in much less friction and, in the dyneema age, are far stronger than the thicker lines of old.

 

[johnalison]

Nor me. We don't have a topping lift

Useful when going up the mast as a back-up line.

 

[Neeves]

Nor me. We don't have a topping lift

We don't have a rod kicker and did not have a topping lift. Boom support came from the lazy jacks. Reefing was fraught, I installed a topping lift - cheaper than installing a rod kicker as the sheaves were there for the topping lift (that I terminated at the mast). Reefing was more comfortable but strumming occurred.

Strumming was an occasional issue - but the lessor of many evils - dropping the boom to be supported by the lazy jacks was the answer.

We had to ensure the topping lift was not touched as if it was released - reefing would cause serious damage. Easily managed (by using the lazyjacks as the back up)


There are many ways to skin a cat (or fillet a fish).

Jonathan

 

[johnalison]

There are many ways to skin a cat

Jonathan

I start from the tail end. What's your method?

 

[[70521]]

Less weight aloft, I suppose. I’ve lost count of the boats I’ve seen using hoofing great halyards, topping lifts and reefing lines. I realise it’s for ease of handling, but thinner lines result in much less friction and, in the dyneema age, are far stronger than the thicker lines of old.

I've stepped down from 12 to 10mm for my halyards and up from 6 to 8mm for my reefing lines.

 

[KevinV]

I start from the tail end. What's your method?

If you have a large enough room then hold the tail and let centripetal force do the work. Simples

 

[Daydream believer]

That's fine if you have a rod kicker...

I hang my boom on a short line & a clip from the backstay where it splits in to two.

 

[Daydream believer]

I start from the tail end. What's your method?

Clever. They stay alive much longer that way

 

[Daydream believer]

My topping lift is the same diameter as the halyard, giving me a spare halyard, never been a problem.

I can't think why people use thinner line for topping lifts.

Because there is no point in having all that extra windage flapping against the sail
Why do you need a spare halyard? Unless you are of the silly habit of disconnecting it from the mainsail at the end of each day, which can always lead to a lost tail end.