Topping lift hum

[Steve Laume]

This one has puzzled me for a long time. I get this hum in my rig when the boat is at anchor or on the mooring. You can hear it through the entire boat and it comes and goes. I was never really sure where it was coming from until today. It turns out it is the topping lift. Raven has a Amsteel line that runs down to a block on the end of the boom. It turns out it is this line that likes to hum and send the sound throughout the entire boat. If I put my hand on it, it stops.

So aside from standing out there with my hand on the thing, how do I get it to stop making this rather annoying noise? I suppose releasing the tension on the main sheet might do it but I like to snug things down when I leave the boat. I know there are little rubber whiskers that go on bow strings to quiet them. Is there anything I could put on my topping lift to make it stop?

Has anyone else ever had a problem with this sort of thing?

It is only mildly annoying but can be persistent, Steve.

[Bob Ohler]

Steve, could you possibly take a digital recording of the "hum" and we'll see if we can't help you better with a possible solution? It could just be out of tune. Have you had your rig tuned lately? If so, did you use a Loos tension gauge, or a tuning fork? Perhaps your boat is trying to contact life in outer space.

I suspect that this is likely to become a (very) long thread, right up there with free wheeling vs. fixed props while under sail.

[Russell]

Well, amsteel is already overkill for a topping lift, change the line and I bet you will lose the resonance (or change the frequency to something less annoying!). But really, without a rigid vang or gallows to support the boom you always need to keep the topping lift taught and any real wind is going to make it hum.

[Brian2]

I had this EXACT same problem on our boat. I'd get up in the middle of the night, wondering who in the heck is idling a boat? It would come and go. It would drive me crazy. One night I went on deck and stood up on the cockpit seat and grabbed hold of the topping lift, and my wife shouted from below "It stopped" and I figured out what was going on.

The problem is that the topping lift is too tight. Slack the main sheet, and the hum will be reduced, but the boom will swing. My in-elegant solution? After cocktails, apps and dinner, and just before retiring for the evening, I loosen the topping lift completely, let the boom rest on top of the dodger, supported by two throwables tied around the boom, and secure the boom from swinging by securing it to a coaming cleat with a spare dockline.

Totally in-elegant, but I am a musician and any low humming will keep me awake all night. I can't ignore it. A boom gallows would be better, but too much trouble. Maybe a spare oar with a fitting for the end of the boom would also work, something like the Rhodes 19s use.

Brian

[David van den Burgh]

Same experience. We took to stuffing a towel in the topping lift at night - at least once or twice.

[Bob Brown]

Ours must have been changed by a PO to cable with line attached about 2' from the boom. No hum but I feel like I'm missing out on all the late night fun.

[Brian2]

Actually, it was no fun to stand on dewey cockpit seats at 2 A.M. trying to figure out what was going on. Ours would hum the most when it was calm or a light breeze, if there was a good breeze blowing, you wouldn't notice it. And, you couuldn't hear it above deck, so it was difficult to figure out. The inside of the cabin became an amplifier for the vibrating topping lift. It sounded like a lobster boat idling nearby.

[Steve Laume]

I am so glad to hear this is not like the voices and others have noticed the same thing.

It is mostly in light breezes that I hear the hum as well. Those quiet times when all is well except for the hum. You go on deck and it is not so noticeable. Down below and it is rather annoying.

Russell, the Amsteel might be overkill if it was a heavier line. I thought about going to cable but was concerned with chafe. My topping lift runs a fixed line from the masthead to a block a couple of feet above the boom end. This used to be a rather bulky Dacron line. When I reworked things I went to 1/8" Amsteel with spliced in thimbles on both ends and a single block on the boom end. This makes for a very light, chafe free, solution that is stronger than the original line. I run standard line through the block and forward to a cleat on the boom at the mast end. It used to be cleated off at the boom end which made no sense at all. It sounds like the hum issue is not the result of the material choice, which makes me happy.

I suppose I could slack off on the main sheet a bit. I have two short lengths of line that attach to the pushpit where the upper life lines end. There are clips on the other end that attach to a bail at the end of the boom. This is quick and easy to do. When not in use the clips go back onto the pushpit. This simple arrangement keeps the boom from swinging while at rest.

I wonder is a short piece of bungee cord clipped between the back stay and the topping lift would eliminate the problem. This would become part of the routine when putting the boat to bed, much like tying off the halyards, Steve.

[Russell]

That was my point about Amsteel, being such a thin line is going to make it resonate at a higher (more annoying) frequency, think guitar strings, if you used a larger diameter line, while a hum might still be present, it might annoy you less.

A friend had an annoying hum on his topping lift and found that tying it to the backstay with a short piece of line when at anchor, in just the right location, got rid of it. But he had to fuss with it a lot each time to find that perfect spot.

[jbenagh]

tying it to the backstay with a short piece of line when at anchor, in just the right location, got rid of it. But he had to fuss with it a lot each time to find that perfect spot.

Christine C's prior owner had two points built up on the backstay with friction tape whose only purpose that I can think of was to mark that spot. He did not leave any piece of line that appeared to be the right weight/length for this purpose.

Jeff

[bottomscraper]

Ours must have been changed by a PO to cable with line attached about 2' from the boom. No hum but I feel like I'm missing out on all the late night fun.

No actually I think yours is original, the Amsteel line a later replacement.

[Oswego John]

Q - Do you know why a topping lift hums?

A - It doesn't know the words.

O J

PS: I heard this over eighty years ago.

[Steve Laume]

Ours must have been changed by a PO to cable with line attached about 2' from the boom. No hum but I feel like I'm missing out on all the late night fun.

No actually I think yours is original, the Amsteel line a later replacement.

Raven had and the manual says a pre stretched Dacron line. Some might have had wire.

So O.J. if I teach it some works do you think it will stop humming?

I was thinking that if I went with a heavier line it would have a deeper sound and it might talk to the whales. Then again I don't usually anchor in areas with whales, Steve.

[Keith]

Like one of the earlier responses I was thinking that a bungy cord from the topping lift to the backstay might solve the problem. MOON Dance should launch in a few days so I will see if I have the same problem.

[Maine_Buzzard]

Can you get to the masthead easily?

Splice in a smaller piece of amsteel and wrap it around the topping lift, about one turn in 10 inches, pulling it tight.

Tie it off at the lower thimble with a few hitches.

Jeep and others do a similar thing on the fm antenna- it keeps the springy wire antenna from shaking at different speeds.

Also, if you twist flat nylon straps before feeding them into the rachet, they won't start flapping on the highway. Same idea, you need only to shift the resonant behavior a bit to squelch it.